11.5 Spring TestContext Framework

The Spring TestContext Framework (located in the org.springframework.test.context package) provides generic, annotation-driven unit and integration testing support that is agnostic of the testing framework in use. The TestContext framework also places a great deal of importance on convention over configuration with reasonable defaults that can be overridden through annotation-based configuration.

In addition to generic testing infrastructure, the TestContext framework provides explicit support for JUnit 4 and TestNG in the form of abstract support classes. For JUnit 4, Spring also provides a custom JUnit Runner and custom JUnit Rules that allow one to write so-called POJO test classes. POJO test classes are not required to extend a particular class hierarchy.

The following section provides an overview of the internals of the TestContext framework. If you are only interested in using the framework and not necessarily interested in extending it with your own custom listeners or custom loaders, feel free to go directly to the configuration (context management, dependency injection, transaction management), support classes, and annotation support sections.

11.5.1 Key abstractions

The core of the framework consists of the TestContextManager class and the TestContext, TestExecutionListener, and SmartContextLoader interfaces. ATestContextManager is created per test class (e.g., for the execution of all test methods within a single test class in JUnit 4). The TestContextManager in turn manages a TestContext that holds the context of the current test. The TestContextManager also updates the state of the TestContext as the test progresses and delegates to TestExecutionListener implementations, which instrument the actual test execution by providing dependency injection, managing transactions, and so on. A SmartContextLoader is responsible for loading an ApplicationContext for a given test class. Consult the javadocs and the Spring test suite for further information and examples of various implementations.

TestContext

TestContext encapsulates the context in which a test is executed, agnostic of the actual testing framework in use, and provides context management and caching support for the test instance for which it is responsible. The TestContext also delegates to a SmartContextLoader to load an ApplicationContext if requested.

TestContextManager

TestContextManager is the main entry point into the Spring TestContext Framework and is responsible for managing a single TestContext and signaling events to each registered TestExecutionListener at well-defined test execution points:

• prior to any before class or before all methods of a particular testing framework
• test instance post-processing
• prior to any before or before each methods of a particular testing framework
• immediately before execution of the test method but after test setup
• immediately after execution of the test method but before test tear down
• after any after or after each methods of a particular testing framework
• after any after class or after all methods of a particular testing framework

TestExecutionListener

TestExecutionListener defines the API for reacting to test execution events published by the TestContextManager with which the listener is registered. SeeSection 11.5.3, “TestExecutionListener configuration”.

Context Loaders

ContextLoader is a strategy interface that was introduced in Spring 2.5 for loading an ApplicationContext for an integration test managed by the Spring TestContext Framework. Implement SmartContextLoader instead of this interface in order to provide support for annotated classes, active bean definition profiles, test property sources, context hierarchies, and WebApplicationContext support.

SmartContextLoader is an extension of the ContextLoader interface introduced in Spring 3.1. The SmartContextLoader SPI supersedes the ContextLoader SPI that was introduced in Spring 2.5. Specifically, a SmartContextLoader can choose to process resource locations, annotated classes, or context initializers. Furthermore, a SmartContextLoader can set active bean definition profiles and test property sources in the context that it loads.

Spring provides the following implementations:

• DelegatingSmartContextLoader: one of two default loaders which delegates internally to an AnnotationConfigContextLoader, a GenericXmlContextLoader, or a GenericGroovyXmlContextLoader depending either on the configuration declared for the test class or on the presence of default locations or default configuration classes. Groovy support is only enabled if Groovy is on the classpath.
• WebDelegatingSmartContextLoader: one of two default loaders which delegates internally to an AnnotationConfigWebContextLoader, a GenericXmlWebContextLoader, or a GenericGroovyXmlWebContextLoader depending either on the configuration declared for the test class or on the presence of default locations or default configuration classes. A web ContextLoader will only be used if @WebAppConfiguration is present on the test class. Groovy support is only enabled if Groovy is on the classpath.
• AnnotationConfigContextLoader: loads a standard ApplicationContext from annotated classes.
• AnnotationConfigWebContextLoader: loads a WebApplicationContext from annotated classes.
• GenericGroovyXmlContextLoader: loads a standard ApplicationContext from resource locations that are either Groovy scripts or XML configuration files.
• GenericGroovyXmlWebContextLoader: loads a WebApplicationContext from resource locations that are either Groovy scripts or XML configuration files.
• GenericXmlContextLoader: loads a standard ApplicationContext from XML resource locations.
• GenericXmlWebContextLoader: loads a WebApplicationContext from XML resource locations.
• GenericPropertiesContextLoader: loads a standard ApplicationContext from Java Properties files.

11.5.2 Bootstrapping the TestContext framework

The default configuration for the internals of the Spring TestContext Framework is sufficient for all common use cases. However, there are times when a development team or third party framework would like to change the default ContextLoader, implement a custom TestContext or ContextCache, augment the default sets ofContextCustomizerFactory and TestExecutionListener implementations, etc. For such low level control over how the TestContext framework operates, Spring provides a bootstrapping strategy.

TestContextBootstrapper defines the SPI for bootstrapping the TestContext framework. A TestContextBootstrapper is used by the TestContextManager to load the TestExecutionListener implementations for the current test and to build the TestContext that it manages. A custom bootstrapping strategy can be configured for a test class (or test class hierarchy) via @BootstrapWith, either directly or as a meta-annotation. If a bootstrapper is not explicitly configured via @BootstrapWith, either the DefaultTestContextBootstrapper or the WebTestContextBootstrapper will be used, depending on the presence of @WebAppConfiguration.

Since the TestContextBootstrapper SPI is likely to change in the future in order to accommodate new requirements, implementers are strongly encouraged not to implement this interface directly but rather to extend AbstractTestContextBootstrapper or one of its concrete subclasses instead.

11.5.3 TestExecutionListener configuration

Spring provides the following TestExecutionListener implementations that are registered by default, exactly in this order.

• ServletTestExecutionListener: configures Servlet API mocks for a WebApplicationContext
• DirtiesContextBeforeModesTestExecutionListener: handles the @DirtiesContext annotation for before modes
• DependencyInjectionTestExecutionListener: provides dependency injection for the test instance
• DirtiesContextTestExecutionListener: handles the @DirtiesContext annotation for after modes
• TransactionalTestExecutionListener: provides transactional test execution with default rollback semantics
• SqlScriptsTestExecutionListener: executes SQL scripts configured via the @Sql annotation

Registering custom TestExecutionListeners

Custom TestExecutionListeners can be registered for a test class and its subclasses via the @TestExecutionListeners annotation. See annotation support and the javadocs for @TestExecutionListeners for details and examples.

Automatic discovery of default TestExecutionListeners

Registering custom TestExecutionListeners via @TestExecutionListeners is suitable for custom listeners that are used in limited testing scenarios; however, it can become cumbersome if a custom listener needs to be used across a test suite. Since Spring Framework 4.1, this issue is addressed via support for automatic discovery of default TestExecutionListener implementations via the SpringFactoriesLoader mechanism.

Specifically, the spring-test module declares all core default TestExecutionListeners under theorg.springframework.test.context.TestExecutionListener key in its META-INF/spring.factories properties file. Third-party frameworks and developers can contribute their own TestExecutionListeners to the list of default listeners in the same manner via their own META-INF/spring.factories properties file.

Ordering TestExecutionListeners

When the TestContext framework discovers default TestExecutionListeners via the aforementioned SpringFactoriesLoader mechanism, the instantiated listeners are sorted using Spring’s AnnotationAwareOrderComparator which honors Spring’s Ordered interface and @Order annotation for ordering. AbstractTestExecutionListener and all default TestExecutionListeners provided by Spring implement Ordered with appropriate values. Third-party frameworks and developers should therefore make sure that their default TestExecutionListeners are registered in the proper order by implementing Ordered or declaring @Order. Consult the javadocs for the getOrder() methods of the core default TestExecutionListeners for details on what values are assigned to each core listener.

Merging TestExecutionListeners

If a custom TestExecutionListener is registered via @TestExecutionListeners, the default listeners will not be registered. In most common testing scenarios, this effectively forces the developer to manually declare all default listeners in addition to any custom listeners. The following listing demonstrates this style of configuration.

@ContextConfiguration
@TestExecutionListeners({
    MyCustomTestExecutionListener.class,
    ServletTestExecutionListener.class,
    DirtiesContextBeforeModesTestExecutionListener.class,
    DependencyInjectionTestExecutionListener.class,
    DirtiesContextTestExecutionListener.class,
    TransactionalTestExecutionListener.class,
    SqlScriptsTestExecutionListener.class
})
public class MyTest {
    // class body...
}

The challenge with this approach is that it requires that the developer know exactly which listeners are registered by default. Moreover, the set of default listeners can change from release to release — for example, SqlScriptsTestExecutionListener was introduced in Spring Framework 4.1, and DirtiesContextBeforeModesTestExecutionListener was introduced in Spring Framework 4.2. Furthermore, third-party frameworks like Spring Security register their own default TestExecutionListeners via the aforementioned automatic discovery mechanism.

To avoid having to be aware of and re-declare all default listeners, the mergeMode attribute of @TestExecutionListeners can be set toMergeMode.MERGE_WITH_DEFAULTS. MERGE_WITH_DEFAULTS indicates that locally declared listeners should be merged with the default listeners. The merging algorithm ensures that duplicates are removed from the list and that the resulting set of merged listeners is sorted according to the semantics of AnnotationAwareOrderComparator as described in the section called “Ordering TestExecutionListeners”. If a listener implements Ordered or is annotated with @Order it can influence the position in which it is merged with the defaults; otherwise, locally declared listeners will simply be appended to the list of default listeners when merged.

For example, if the MyCustomTestExecutionListener class in the previous example configures its order value (for example, 500) to be less than the order of theServletTestExecutionListener (which happens to be 1000), the MyCustomTestExecutionListener can then be automatically merged with the list of defaults in front of the ServletTestExecutionListener, and the previous example could be replaced with the following.

@ContextConfiguration
@TestExecutionListeners(
    listeners = MyCustomTestExecutionListener.class,
    mergeMode = MERGE_WITH_DEFAULTS
)
public class MyTest {
    // class body...
}

11.5.4 Context management

Each TestContext provides context management and caching support for the test instance it is responsible for. Test instances do not automatically receive access to the configured ApplicationContext. However, if a test class implements the ApplicationContextAware interface, a reference to the ApplicationContext is supplied to the test instance. Note that AbstractJUnit4SpringContextTests and AbstractTestNGSpringContextTests implement ApplicationContextAwareand therefore provide access to the ApplicationContext automatically.

As an alternative to implementing the ApplicationContextAware interface, you can inject the application context for your test class through the @Autowired annotation on either a field or setter method. For example:*@RunWith(SpringRunner.class)**@ContextConfiguration*public class MyTest { **@Autowired** private ApplicationContext applicationContext; // class body...}Similarly, if your test is configured to load a WebApplicationContext, you can inject the web application context into your test as follows:*@RunWith(SpringRunner.class)***@WebAppConfiguration***@ContextConfiguration*public class MyWebAppTest { **@Autowired** private WebApplicationContext wac; // class body...}Dependency injection via @Autowired is provided by the DependencyInjectionTestExecutionListener which is configured by default (seeSection 11.5.5, “Dependency injection of test fixtures”).

Test classes that use the TestContext framework do not need to extend any particular class or implement a specific interface to configure their application context. Instead, configuration is achieved simply by declaring the @ContextConfiguration annotation at the class level. If your test class does not explicitly declare application context resource locations or annotated classes, the configured ContextLoader determines how to load a context from a default location or default configuration classes. In addition to context resource locations and annotated classes, an application context can also be configured via application context initializers.

The following sections explain how to configure an ApplicationContext via XML configuration files, Groovy scripts, annotated classes (typically @Configurationclasses), or context initializers using Spring’s @ContextConfiguration annotation. Alternatively, you can implement and configure your own custom SmartContextLoader for advanced use cases.

Context configuration with XML resources

To load an ApplicationContext for your tests using XML configuration files, annotate your test class with @ContextConfiguration and configure the locationsattribute with an array that contains the resource locations of XML configuration metadata. A plain or relative path — for example "context.xml" — will be treated as a classpath resource that is relative to the package in which the test class is defined. A path starting with a slash is treated as an absolute classpath location, for example"/org/example/config.xml". A path which represents a resource URL (i.e., a path prefixed with classpath:, file:, http:, etc.) will be used as is.

@RunWith(SpringRunner.class)
// ApplicationContext will be loaded from "/app-config.xml" and
// "/test-config.xml" in the root of the classpath
@ContextConfiguration(locations={"/app-config.xml", "/test-config.xml"})
public class MyTest {
    // class body...
}

@ContextConfiguration supports an alias for the locations attribute through the standard Java value attribute. Thus, if you do not need to declare additional attributes in @ContextConfiguration, you can omit the declaration of the locations attribute name and declare the resource locations by using the shorthand format demonstrated in the following example.

@RunWith(SpringRunner.class)
@ContextConfiguration({"/app-config.xml", "/test-config.xml"})
public class MyTest {
    // class body...
}

If you omit both the locations and value attributes from the @ContextConfiguration annotation, the TestContext framework will attempt to detect a default XML resource location. Specifically, GenericXmlContextLoader and GenericXmlWebContextLoader detect a default location based on the name of the test class. If your class is named com.example.MyTest, GenericXmlContextLoader loads your application context from "classpath:com/example/MyTest-context.xml".

package com.example;

@RunWith(SpringRunner.class)
// ApplicationContext will be loaded from
// "classpath:com/example/MyTest-context.xml"
@ContextConfiguration
public class MyTest {
    // class body...
}

Context configuration with Groovy scripts

To load an ApplicationContext for your tests using Groovy scripts that utilize the Groovy Bean Definition DSL, annotate your test class with@ContextConfiguration and configure the locations or value attribute with an array that contains the resource locations of Groovy scripts. Resource lookup semantics for Groovy scripts are the same as those described for XML configuration files.

Support for using Groovy scripts to load an ApplicationContext in the Spring TestContext Framework is enabled automatically if Groovy is on the classpath.

@RunWith(SpringRunner.class)
// ApplicationContext will be loaded from "/AppConfig.groovy" and
// "/TestConfig.groovy" in the root of the classpath
@ContextConfiguration({"/AppConfig.groovy", "/TestConfig.Groovy"})
public class MyTest {
    // class body...
}

If you omit both the locations and value attributes from the @ContextConfiguration annotation, the TestContext framework will attempt to detect a default Groovy script. Specifically, GenericGroovyXmlContextLoader and GenericGroovyXmlWebContextLoader detect a default location based on the name of the test class. If your class is named com.example.MyTest, the Groovy context loader will load your application context from "classpath:com/example/MyTestContext.groovy".

package com.example;

@RunWith(SpringRunner.class)
// ApplicationContext will be loaded from
// "classpath:com/example/MyTestContext.groovy"
@ContextConfiguration
public class MyTest {
    // class body...
}

Both XML configuration files and Groovy scripts can be declared simultaneously via the locations or value attribute of @ContextConfiguration. If the path to a configured resource location ends with .xml it will be loaded using an XmlBeanDefinitionReader; otherwise it will be loaded using a GroovyBeanDefinitionReader.The following listing demonstrates how to combine both in an integration test.*@RunWith(SpringRunner.class)*// ApplicationContext will be loaded from// "/app-config.xml" and "/TestConfig.groovy"*@ContextConfiguration({ "/app-config.xml", "/TestConfig.groovy" })*public class MyTest { // class body...}

Context configuration with annotated classes

To load an ApplicationContext for your tests using annotated classes (see Section 3.12, “Java-based container configuration”), annotate your test class with @ContextConfiguration and configure the classes attribute with an array that contains references to annotated classes.

@RunWith(SpringRunner.class)
// ApplicationContext will be loaded from AppConfig and TestConfig
@ContextConfiguration(classes = {AppConfig.class, TestConfig.class})
public class MyTest {
    // class body...
}

The term annotated class can refer to any of the following.A class annotated with @ConfigurationA component (i.e., a class annotated with @Component, @Service, @Repository, etc.)A JSR-330 compliant class that is annotated with javax.inject annotationsAny other class that contains @Bean-methodsConsult the javadocs of @Configuration and @Bean for further information regarding the configuration and semantics of annotated classes, paying special attention to the discussion of @Bean Lite Mode.

If you omit the classes attribute from the @ContextConfiguration annotation, the TestContext framework will attempt to detect the presence of default configuration classes. Specifically, AnnotationConfigContextLoader and AnnotationConfigWebContextLoader will detect all static nested classes of the test class that meet the requirements for configuration class implementations as specified in the @Configuration javadocs. In the following example, the OrderServiceTest class declares a static nested configuration class named Config that will be automatically used to load the ApplicationContext for the test class. Note that the name of the configuration class is arbitrary. In addition, a test class can contain more than one static nested configuration class if desired.

@RunWith(SpringRunner.class)
// ApplicationContext will be loaded from the
// static nested Config class
@ContextConfiguration
public class OrderServiceTest {

    @Configuration
    static class Config {

        // this bean will be injected into the OrderServiceTest class
        @Bean
        public OrderService orderService() {
            OrderService orderService = new OrderServiceImpl();
            // set properties, etc.
            return orderService;
        }
    }

    @Autowired
    private OrderService orderService;

    @Test
    public void testOrderService() {
        // test the orderService
    }

}

Mixing XML, Groovy scripts, and annotated classes

It may sometimes be desirable to mix XML configuration files, Groovy scripts, and annotated classes (i.e., typically @Configuration classes) to configure anApplicationContext for your tests. For example, if you use XML configuration in production, you may decide that you want to use @Configuration classes to configure specific Spring-managed components for your tests, or vice versa.

Furthermore, some third-party frameworks (like Spring Boot) provide first-class support for loading an ApplicationContext from different types of resources simultaneously (e.g., XML configuration files, Groovy scripts, and @Configuration classes). The Spring Framework historically has not supported this for standard deployments. Consequently, most of the SmartContextLoader implementations that the Spring Framework delivers in the spring-test module support only one resource type per test context; however, this does not mean that you cannot use both. One exception to the general rule is that the GenericGroovyXmlContextLoaderand GenericGroovyXmlWebContextLoader support both XML configuration files and Groovy scripts simultaneously. Furthermore, third-party frameworks may choose to support the declaration of both locations and classes via @ContextConfiguration, and with the standard testing support in the TestContext framework, you have the following options.

If you want to use resource locations (e.g., XML or Groovy) and @Configuration classes to configure your tests, you will have to pick one as the entry point, and that one will have to include or import the other. For example, in XML or Groovy scripts you can include @Configuration classes via component scanning or define them as normal Spring beans; whereas, in a @Configuration class you can use @ImportResource to import XML configuration files or Groovy scripts. Note that this behavior is semantically equivalent to how you configure your application in production: in production configuration you will define either a set of XML or Groovy resource locations or a set of @Configuration classes that your production ApplicationContext will be loaded from, but you still have the freedom to include or import the other type of configuration.

Context configuration with context initializers

To configure an ApplicationContext for your tests using context initializers, annotate your test class with @ContextConfiguration and configure the initializers attribute with an array that contains references to classes that implement ApplicationContextInitializer. The declared context initializers will then be used to initialize the ConfigurableApplicationContext that is loaded for your tests. Note that the concrete ConfigurableApplicationContext type supported by each declared initializer must be compatible with the type of ApplicationContext created by the SmartContextLoader in use (i.e., typically a GenericApplicationContext). Furthermore, the order in which the initializers are invoked depends on whether they implement Spring’s Ordered interface or are annotated with Spring’s @Order annotation or the standard @Priority annotation.

@RunWith(SpringRunner.class)
// ApplicationContext will be loaded from TestConfig
// and initialized by TestAppCtxInitializer
@ContextConfiguration(
    classes = TestConfig.class,
    initializers = TestAppCtxInitializer.class)
public class MyTest {
    // class body...
}

It is also possible to omit the declaration of XML configuration files, Groovy scripts, or annotated classes in @ContextConfiguration entirely and instead declare onlyApplicationContextInitializer classes which are then responsible for registering beans in the context — for example, by programmatically loading bean definitions from XML files or configuration classes.

@RunWith(SpringRunner.class)
// ApplicationContext will be initialized by EntireAppInitializer
// which presumably registers beans in the context
@ContextConfiguration(initializers = EntireAppInitializer.class)
public class MyTest {
    // class body...
}

Context configuration inheritance

@ContextConfiguration supports boolean inheritLocations and inheritInitializers attributes that denote whether resource locations or annotated classes and context initializers declared by superclasses should be inherited. The default value for both flags is true. This means that a test class inherits the resource locations or annotated classes as well as the context initializers declared by any superclasses. Specifically, the resource locations or annotated classes for a test class are appended to the list of resource locations or annotated classes declared by superclasses. Similarly, the initializers for a given test class will be added to the set of initializers defined by test superclasses. Thus, subclasses have the option of extending the resource locations, annotated classes, or context initializers.

If the inheritLocations or inheritInitializers attribute in @ContextConfiguration is set to false, the resource locations or annotated classes and the context initializers, respectively, for the test class shadow and effectively replace the configuration defined by superclasses.

In the following example that uses XML resource locations, the ApplicationContext for ExtendedTest will be loaded from "base-config.xml" and "extended-config.xml", in that order. Beans defined in "extended-config.xml" may therefore override (i.e., replace) those defined in "base-config.xml".

@RunWith(SpringRunner.class)
// ApplicationContext will be loaded from "/base-config.xml"
// in the root of the classpath
@ContextConfiguration("/base-config.xml")
public class BaseTest {
    // class body...
}

// ApplicationContext will be loaded from "/base-config.xml" and
// "/extended-config.xml" in the root of the classpath
@ContextConfiguration("/extended-config.xml")
public class ExtendedTest extends BaseTest {
    // class body...
}

Similarly, in the following example that uses annotated classes, the ApplicationContext for ExtendedTest will be loaded from the BaseConfig andExtendedConfig classes, in that order. Beans defined in ExtendedConfig may therefore override (i.e., replace) those defined in BaseConfig.

@RunWith(SpringRunner.class)
// ApplicationContext will be loaded from BaseConfig
@ContextConfiguration(classes = BaseConfig.class)
public class BaseTest {
    // class body...
}

// ApplicationContext will be loaded from BaseConfig and ExtendedConfig
@ContextConfiguration(classes = ExtendedConfig.class)
public class ExtendedTest extends BaseTest {
    // class body...
}

In the following example that uses context initializers, the ApplicationContext for ExtendedTest will be initialized using BaseInitializer andExtendedInitializer. Note, however, that the order in which the initializers are invoked depends on whether they implement Spring’s Ordered interface or are annotated with Spring’s @Order annotation or the standard @Priority annotation.

@RunWith(SpringRunner.class)
// ApplicationContext will be initialized by BaseInitializer
@ContextConfiguration(initializers = BaseInitializer.class)
public class BaseTest {
    // class body...
}

// ApplicationContext will be initialized by BaseInitializer
// and ExtendedInitializer
@ContextConfiguration(initializers = ExtendedInitializer.class)
public class ExtendedTest extends BaseTest {
    // class body...
}

Context configuration with environment profiles

Spring 3.1 introduced first-class support in the framework for the notion of environments and profiles (a.k.a., bean definition profiles), and integration tests can be configured to activate particular bean definition profiles for various testing scenarios. This is achieved by annotating a test class with the @ActiveProfiles annotation and supplying a list of profiles that should be activated when loading the ApplicationContext for the test.

@ActiveProfiles may be used with any implementation of the new SmartContextLoader SPI, but @ActiveProfiles is not supported with implementations of the older ContextLoader SPI.

Let’s take a look at some examples with XML configuration and @Configuration classes.

<!-- app-config.xml -->
<beans xmlns="http://www.springframework.org/schema/beans"
    xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
    xmlns:jdbc="http://www.springframework.org/schema/jdbc"
    xmlns:jee="http://www.springframework.org/schema/jee"
    xsi:schemaLocation="...">

    <bean id="transferService"
            class="com.bank.service.internal.DefaultTransferService">
        <constructor-arg ref="accountRepository"/>
        <constructor-arg ref="feePolicy"/>
    </bean>

    <bean id="accountRepository"
            class="com.bank.repository.internal.JdbcAccountRepository">
        <constructor-arg ref="dataSource"/>
    </bean>

    <bean id="feePolicy"
        class="com.bank.service.internal.ZeroFeePolicy"/>

    <beans profile="dev">
        <jdbc:embedded-database id="dataSource">
            <jdbc:script
                location="classpath:com/bank/config/sql/schema.sql"/>
            <jdbc:script
                location="classpath:com/bank/config/sql/test-data.sql"/>
        </jdbc:embedded-database>
    </beans>

    <beans profile="production">
        <jee:jndi-lookup id="dataSource" jndi-name="java:comp/env/jdbc/datasource"/>
    </beans>

    <beans profile="default">
        <jdbc:embedded-database id="dataSource">
            <jdbc:script
                location="classpath:com/bank/config/sql/schema.sql"/>
        </jdbc:embedded-database>
    </beans>

</beans>

package com.bank.service;

@RunWith(SpringRunner.class)
// ApplicationContext will be loaded from "classpath:/app-config.xml"
@ContextConfiguration("/app-config.xml")
@ActiveProfiles("dev")
public class TransferServiceTest {

    @Autowired
    private TransferService transferService;

    @Test
    public void testTransferService() {
        // test the transferService
    }
}

When TransferServiceTest is run, its ApplicationContext will be loaded from the app-config.xml configuration file in the root of the classpath. If you inspectapp-config.xml you’ll notice that the accountRepository bean has a dependency on a dataSource bean; however, dataSource is not defined as a top-level bean. Instead, dataSource is defined three times: in the production profile, the dev profile, and the default profile.

By annotating TransferServiceTest with @ActiveProfiles("dev") we instruct the Spring TestContext Framework to load the ApplicationContext with the active profiles set to {"dev"}. As a result, an embedded database will be created and populated with test data, and the accountRepository bean will be wired with a reference to the development DataSource. And that’s likely what we want in an integration test.

It is sometimes useful to assign beans to a default profile. Beans within the default profile are only included when no other profile is specifically activated. This can be used to define fallback beans to be used in the application’s default state. For example, you may explicitly provide a data source for dev and production profiles, but define an in-memory data source as a default when neither of these is active.

The following code listings demonstrate how to implement the same configuration and integration test but using @Configuration classes instead of XML.

@Configuration
@Profile("dev")
public class StandaloneDataConfig {

    @Bean
    public DataSource dataSource() {
        return new EmbeddedDatabaseBuilder()
            .setType(EmbeddedDatabaseType.HSQL)
            .addScript("classpath:com/bank/config/sql/schema.sql")
            .addScript("classpath:com/bank/config/sql/test-data.sql")
            .build();
    }
}

@Configuration
@Profile("production")
public class JndiDataConfig {

    @Bean(destroyMethod="")
    public DataSource dataSource() throws Exception {
        Context ctx = new InitialContext();
        return (DataSource) ctx.lookup("java:comp/env/jdbc/datasource");
    }
}

@Configuration
@Profile("default")
public class DefaultDataConfig {

    @Bean
    public DataSource dataSource() {
        return new EmbeddedDatabaseBuilder()
            .setType(EmbeddedDatabaseType.HSQL)
            .addScript("classpath:com/bank/config/sql/schema.sql")
            .build();
    }
}

@Configuration
public class TransferServiceConfig {

    @Autowired DataSource dataSource;

    @Bean
    public TransferService transferService() {
        return new DefaultTransferService(accountRepository(), feePolicy());
    }

    @Bean
    public AccountRepository accountRepository() {
        return new JdbcAccountRepository(dataSource);
    }

    @Bean
    public FeePolicy feePolicy() {
        return new ZeroFeePolicy();
    }

}

package com.bank.service;

@RunWith(SpringRunner.class)
@ContextConfiguration(classes = {
        TransferServiceConfig.class,
        StandaloneDataConfig.class,
        JndiDataConfig.class,
        DefaultDataConfig.class})
@ActiveProfiles("dev")
public class TransferServiceTest {

    @Autowired
    private TransferService transferService;

    @Test
    public void testTransferService() {
        // test the transferService
    }
}

In this variation, we have split the XML configuration into four independent @Configuration classes:

• TransferServiceConfig: acquires a dataSource via dependency injection using @Autowired
• StandaloneDataConfig: defines a dataSource for an embedded database suitable for developer tests
• JndiDataConfig: defines a dataSource that is retrieved from JNDI in a production environment
• DefaultDataConfig: defines a dataSource for a default embedded database in case no profile is active

As with the XML-based configuration example, we still annotate TransferServiceTest with @ActiveProfiles("dev"), but this time we specify all four configuration classes via the @ContextConfiguration annotation. The body of the test class itself remains completely unchanged.

It is often the case that a single set of profiles is used across multiple test classes within a given project. Thus, to avoid duplicate declarations of the @ActiveProfilesannotation it is possible to declare @ActiveProfiles once on a base class, and subclasses will automatically inherit the @ActiveProfiles configuration from the base class. In the following example, the declaration of @ActiveProfiles (as well as other annotations) has been moved to an abstract superclass, AbstractIntegrationTest.

package com.bank.service;

@RunWith(SpringRunner.class)
@ContextConfiguration(classes = {
        TransferServiceConfig.class,
        StandaloneDataConfig.class,
        JndiDataConfig.class,
        DefaultDataConfig.class})
@ActiveProfiles("dev")
public abstract class AbstractIntegrationTest {
}

package com.bank.service;

// "dev" profile inherited from superclass
public class TransferServiceTest extends AbstractIntegrationTest {

    @Autowired
    private TransferService transferService;

    @Test
    public void testTransferService() {
        // test the transferService
    }
}

@ActiveProfiles also supports an inheritProfiles attribute that can be used to disable the inheritance of active profiles.

package com.bank.service;

// "dev" profile overridden with "production"
@ActiveProfiles(profiles = "production", inheritProfiles = false)
public class ProductionTransferServiceTest extends AbstractIntegrationTest {
    // test body
}

Furthermore, it is sometimes necessary to resolve active profiles for tests programmatically instead of declaratively — for example, based on:

• the current operating system
• whether tests are being executed on a continuous integration build server
• the presence of certain environment variables
• the presence of custom class-level annotations
• etc.

To resolve active bean definition profiles programmatically, simply implement a custom ActiveProfilesResolver and register it via the resolver attribute of@ActiveProfiles. The following example demonstrates how to implement and register a custom OperatingSystemActiveProfilesResolver. For further information, refer to the corresponding javadocs.

package com.bank.service;

// "dev" profile overridden programmatically via a custom resolver
@ActiveProfiles(
    resolver = OperatingSystemActiveProfilesResolver.class,
    inheritProfiles = false)
public class TransferServiceTest extends AbstractIntegrationTest {
    // test body
}

package com.bank.service.test;

public class OperatingSystemActiveProfilesResolver implements ActiveProfilesResolver {

    @Override
    String[] resolve(Class<?> testClass) {
        String profile = ...;
        // determine the value of profile based on the operating system
        return new String[] {profile};
    }
}

Context configuration with test property sources

Spring 3.1 introduced first-class support in the framework for the notion of an environment with a hierarchy of property sources, and since Spring 4.1 integration tests can be configured with test-specific property sources. In contrast to the @PropertySource annotation used on @Configuration classes, the @TestPropertySourceannotation can be declared on a test class to declare resource locations for test properties files or inlined properties. These test property sources will be added to the set of PropertySources in the Environment for the ApplicationContext loaded for the annotated integration test.

@TestPropertySource may be used with any implementation of the SmartContextLoader SPI, but @TestPropertySource is not supported with implementations of the older ContextLoader SPI.Implementations of SmartContextLoader gain access to merged test property source values via the getPropertySourceLocations() and getPropertySourceProperties() methods in MergedContextConfiguration.

Declaring test property sources

Test properties files can be configured via the locations or value attribute of @TestPropertySource as shown in the following example.

Both traditional and XML-based properties file formats are supported — for example, "classpath:/com/example/test.properties" or "file:///path/to/file.xml".

Each path will be interpreted as a Spring Resource. A plain path — for example, "test.properties" — will be treated as a classpath resource that is relative to the package in which the test class is defined. A path starting with a slash will be treated as an absolute classpath resource, for example: "/org/example/test.xml". A path which references a URL (e.g., a path prefixed with classpath:, file:, http:, etc.) will be loaded using the specified resource protocol. Resource location wildcards (e.g. ***/**.properties) are not permitted: each location must evaluate to exactly one .properties or .xml resource.

@ContextConfiguration
@TestPropertySource("/test.properties")
public class MyIntegrationTests {
    // class body...
}

Inlined properties in the form of key-value pairs can be configured via the properties attribute of @TestPropertySource as shown in the following example. All key-value pairs will be added to the enclosing Environment as a single test PropertySource with the highest precedence.

The supported syntax for key-value pairs is the same as the syntax defined for entries in a Java properties file:

• "key=value"
• "key:value"
• "key value"

@ContextConfiguration
@TestPropertySource(properties = {"timezone = GMT", "port: 4242"})
public class MyIntegrationTests {
    // class body...
}

Default properties file detection

If @TestPropertySource is declared as an empty annotation (i.e., without explicit values for the locations or properties attributes), an attempt will be made to detect a default properties file relative to the class that declared the annotation. For example, if the annotated test class is com.example.MyTest, the corresponding default properties file is "classpath:com/example/MyTest.properties". If the default cannot be detected, an IllegalStateException will be thrown.

Precedence

Test property sources have higher precedence than those loaded from the operating system’s environment or Java system properties as well as property sources added by the application declaratively via @PropertySource or programmatically. Thus, test property sources can be used to selectively override properties defined in system and application property sources. Furthermore, inlined properties have higher precedence than properties loaded from resource locations.

In the following example, the timezone and port properties as well as any properties defined in "/test.properties" will override any properties of the same name that are defined in system and application property sources. Furthermore, if the "/test.properties" file defines entries for the timezone and port properties those will be overridden by the inlined properties declared via the properties attribute.

@ContextConfiguration
@TestPropertySource(
    locations = "/test.properties",
    properties = {"timezone = GMT", "port: 4242"}
)
public class MyIntegrationTests {
    // class body...
}

Inheriting and overriding test property sources

@TestPropertySource supports boolean inheritLocations and inheritProperties attributes that denote whether resource locations for properties files and inlined properties declared by superclasses should be inherited. The default value for both flags is true. This means that a test class inherits the locations and inlined properties declared by any superclasses. Specifically, the locations and inlined properties for a test class are appended to the locations and inlined properties declared by superclasses. Thus, subclasses have the option of extending the locations and inlined properties. Note that properties that appear later will shadow (i.e.., override) properties of the same name that appear earlier. In addition, the aforementioned precedence rules apply for inherited test property sources as well.

If the inheritLocations or inheritProperties attribute in @TestPropertySource is set to false, the locations or inlined properties, respectively, for the test class shadow and effectively replace the configuration defined by superclasses.

In the following example, the ApplicationContext for BaseTest will be loaded using only the "base.properties" file as a test property source. In contrast, theApplicationContext for ExtendedTest will be loaded using the "base.properties" and "extended.properties" files as test property source locations.

@TestPropertySource("base.properties")
@ContextConfiguration
public class BaseTest {
    // ...
}

@TestPropertySource("extended.properties")
@ContextConfiguration
public class ExtendedTest extends BaseTest {
    // ...
}

In the following example, the ApplicationContext for BaseTest will be loaded using only the inlined key1 property. In contrast, the ApplicationContext for ExtendedTest will be loaded using the inlined key1 and key2 properties.

@TestPropertySource(properties = "key1 = value1")
@ContextConfiguration
public class BaseTest {
    // ...
}

@TestPropertySource(properties = "key2 = value2")
@ContextConfiguration
public class ExtendedTest extends BaseTest {
    // ...
}

Loading a WebApplicationContext

Spring 3.2 introduced support for loading a WebApplicationContext in integration tests. To instruct the TestContext framework to load a WebApplicationContextinstead of a standard ApplicationContext, simply annotate the respective test class with @WebAppConfiguration.

The presence of @WebAppConfiguration on your test class instructs the TestContext framework (TCF) that a WebApplicationContext (WAC) should be loaded for your integration tests. In the background the TCF makes sure that a MockServletContext is created and supplied to your test’s WAC. By default the base resource path for your MockServletContext will be set to "src/main/webapp". This is interpreted as a path relative to the root of your JVM (i.e., normally the path to your project). If you’re familiar with the directory structure of a web application in a Maven project, you’ll know that "src/main/webapp" is the default location for the root of your WAR. If you need to override this default, simply provide an alternate path to the @WebAppConfiguration annotation (e.g., @WebAppConfiguration("src/test/webapp")). If you wish to reference a base resource path from the classpath instead of the file system, just use Spring’s classpath: prefix.

Please note that Spring’s testing support for WebApplicationContexts is on par with its support for standard ApplicationContexts. When testing with a WebApplicationContext you are free to declare XML configuration files, Groovy scripts, or @Configuration classes via @ContextConfiguration. You are of course also free to use any other test annotations such as @ActiveProfiles, @TestExecutionListeners, @Sql, @Rollback, etc.

The following examples demonstrate some of the various configuration options for loading a WebApplicationContext.

Conventions.

@RunWith(SpringRunner.class)

// defaults to "file:src/main/webapp"
@WebAppConfiguration

// detects "WacTests-context.xml" in same package
// or static nested @Configuration class
@ContextConfiguration

public class WacTests {
    //...
}

The above example demonstrates the TestContext framework’s support for convention over configuration. If you annotate a test class with @WebAppConfigurationwithout specifying a resource base path, the resource path will effectively default to "file:src/main/webapp". Similarly, if you declare @ContextConfiguration without specifying resource locations, annotated classes, or context initializers, Spring will attempt to detect the presence of your configuration using conventions (i.e., "WacTests-context.xml" in the same package as the WacTests class or static nested @Configuration classes).

Default resource semantics.

@RunWith(SpringRunner.class)

// file system resource
@WebAppConfiguration("webapp")

// classpath resource
@ContextConfiguration("/spring/test-servlet-config.xml")

public class WacTests {
    //...
}

This example demonstrates how to explicitly declare a resource base path with @WebAppConfiguration and an XML resource location with @ContextConfiguration. The important thing to note here is the different semantics for paths with these two annotations. By default, @WebAppConfiguration resource paths are file system based; whereas, @ContextConfiguration resource locations are classpath based.

Explicit resource semantics.

@RunWith(SpringRunner.class)

// classpath resource
@WebAppConfiguration("classpath:test-web-resources")

// file system resource
@ContextConfiguration("file:src/main/webapp/WEB-INF/servlet-config.xml")

public class WacTests {
    //...
}

In this third example, we see that we can override the default resource semantics for both annotations by specifying a Spring resource prefix. Contrast the comments in this example with the previous example.

To provide comprehensive web testing support, Spring 3.2 introduced a ServletTestExecutionListener that is enabled by default. When testing against aWebApplicationContext this TestExecutionListener sets up default thread-local state via Spring Web’s RequestContextHolder before each test method and creates a MockHttpServletRequest, MockHttpServletResponse, and ServletWebRequest based on the base resource path configured via @WebAppConfiguration. ServletTestExecutionListener also ensures that the MockHttpServletResponse and ServletWebRequest can be injected into the test instance, and once the test is complete it cleans up thread-local state.

Once you have a WebApplicationContext loaded for your test you might find that you need to interact with the web mocks — for example, to set up your test fixture or to perform assertions after invoking your web component. The following example demonstrates which mocks can be autowired into your test instance. Note that theWebApplicationContext and MockServletContext are both cached across the test suite; whereas, the other mocks are managed per test method by theServletTestExecutionListener.

Injecting mocks.

@WebAppConfiguration
@ContextConfiguration
public class WacTests {

    @Autowired
    WebApplicationContext wac; // cached

    @Autowired
    MockServletContext servletContext; // cached

    @Autowired
    MockHttpSession session;

    @Autowired
    MockHttpServletRequest request;

    @Autowired
    MockHttpServletResponse response;

    @Autowired
    ServletWebRequest webRequest;

    //...
}

Context caching

Once the TestContext framework loads an ApplicationContext (or WebApplicationContext) for a test, that context will be cached and reused for all subsequent tests that declare the same unique context configuration within the same test suite. To understand how caching works, it is important to understand what is meant by unique and test suite.

An ApplicationContext can be uniquely identified by the combination of configuration parameters that are used to load it. Consequently, the unique combination of configuration parameters are used to generate a key under which the context is cached. The TestContext framework uses the following configuration parameters to build the context cache key:

• locations (from @ContextConfiguration)
• classes (from @ContextConfiguration)
• contextInitializerClasses (from @ContextConfiguration)
• contextCustomizers (from ContextCustomizerFactory)
• contextLoader (from @ContextConfiguration)
• parent (from @ContextHierarchy)
• activeProfiles (from @ActiveProfiles)
• propertySourceLocations (from @TestPropertySource)
• propertySourceProperties (from @TestPropertySource)
• resourceBasePath (from @WebAppConfiguration)

For example, if TestClassA specifies {"app-config.xml", "test-config.xml"} for the locations (or value) attribute of @ContextConfiguration, the TestContext framework will load the corresponding ApplicationContext and store it in a static context cache under a key that is based solely on those locations. So if TestClassB also defines {"app-config.xml", "test-config.xml"} for its locations (either explicitly or implicitly through inheritance) but does not define @WebAppConfiguration, a different ContextLoader, different active profiles, different context initializers, different test property sources, or a different parent context, then the same ApplicationContext will be shared by both test classes. This means that the setup cost for loading an application context is incurred only once (per test suite), and subsequent test execution is much faster.

The Spring TestContext framework stores application contexts in a static cache. This means that the context is literally stored in a static variable. In other words, if tests execute in separate processes the static cache will be cleared between each test execution, and this will effectively disable the caching mechanism.To benefit from the caching mechanism, all tests must run within the same process or test suite. This can be achieved by executing all tests as a group within an IDE. Similarly, when executing tests with a build framework such as Ant, Maven, or Gradle it is important to make sure that the build framework does not fork between tests. For example, if the forkMode for the Maven Surefire plug-in is set to always or pertest, the TestContext framework will not be able to cache application contexts between test classes and the build process will run significantly slower as a result.

Since Spring Framework 4.3, the size of the context cache is bounded with a default maximum size of 32. Whenever the maximum size is reached, a least recently used(LRU) eviction policy is used to evict and close stale contexts. The maximum size can be configured from the command line or a build script by setting a JVM system property named spring.test.context.cache.maxSize. As an alternative, the same property can be set programmatically via the SpringProperties API.

Since having a large number of application contexts loaded within a given test suite can cause the suite to take an unnecessarily long time to execute, it is often beneficial to know exactly how many contexts have been loaded and cached. To view the statistics for the underlying context cache, simply set the log level for theorg.springframework.test.context.cache logging category to DEBUG.

In the unlikely case that a test corrupts the application context and requires reloading — for example, by modifying a bean definition or the state of an application object — you can annotate your test class or test method with @DirtiesContext (see the discussion of @DirtiesContext in Section 11.4.1, “Spring Testing Annotations”). This instructs Spring to remove the context from the cache and rebuild the application context before executing the next test. Note that support for the @DirtiesContext annotation is provided by the DirtiesContextBeforeModesTestExecutionListener and the DirtiesContextTestExecutionListener which are enabled by default.

Context hierarchies

When writing integration tests that rely on a loaded Spring ApplicationContext, it is often sufficient to test against a single context; however, there are times when it is beneficial or even necessary to test against a hierarchy of ApplicationContexts. For example, if you are developing a Spring MVC web application you will typically have a root WebApplicationContext loaded via Spring’s ContextLoaderListener and a child WebApplicationContext loaded via Spring’s DispatcherServlet. This results in a parent-child context hierarchy where shared components and infrastructure configuration are declared in the root context and consumed in the child context by web-specific components. Another use case can be found in Spring Batch applications where you often have a parent context that provides configuration for shared batch infrastructure and a child context for the configuration of a specific batch job.

Since Spring Framework 3.2.2, it is possible to write integration tests that use context hierarchies by declaring context configuration via the @ContextHierarchyannotation, either on an individual test class or within a test class hierarchy. If a context hierarchy is declared on multiple classes within a test class hierarchy it is also possible to merge or override the context configuration for a specific, named level in the context hierarchy. When merging configuration for a given level in the hierarchy the configuration resource type (i.e., XML configuration files or annotated classes) must be consistent; otherwise, it is perfectly acceptable to have different levels in a context hierarchy configured using different resource types.

The following JUnit 4 based examples demonstrate common configuration scenarios for integration tests that require the use of context hierarchies.

ControllerIntegrationTests represents a typical integration testing scenario for a Spring MVC web application by declaring a context hierarchy consisting of two levels, one for the root WebApplicationContext (loaded using the TestAppConfig @Configuration class) and one for the dispatcher servletWebApplicationContext (loaded using the WebConfig @Configuration class). The WebApplicationContext that is autowired into the test instance is the one for the child context (i.e., the lowest context in the hierarchy).

@RunWith(SpringRunner.class)
@WebAppConfiguration
@ContextHierarchy({
    @ContextConfiguration(classes = TestAppConfig.class),
    @ContextConfiguration(classes = WebConfig.class)
})
public class ControllerIntegrationTests {

    @Autowired
    private WebApplicationContext wac;

    // ...
}

The following test classes define a context hierarchy within a test class hierarchy. AbstractWebTests declares the configuration for a root WebApplicationContext in a Spring-powered web application. Note, however, that AbstractWebTests does not declare @ContextHierarchy; consequently, subclasses of AbstractWebTestscan optionally participate in a context hierarchy or simply follow the standard semantics for @ContextConfiguration. SoapWebServiceTests and RestWebServiceTests both extend AbstractWebTests and define a context hierarchy via @ContextHierarchy. The result is that three application contexts will be loaded (one for each declaration of @ContextConfiguration), and the application context loaded based on the configuration in AbstractWebTests will be set as the parent context for each of the contexts loaded for the concrete subclasses.

@RunWith(SpringRunner.class)
@WebAppConfiguration
@ContextConfiguration("file:src/main/webapp/WEB-INF/applicationContext.xml")
public abstract class AbstractWebTests {}

@ContextHierarchy(@ContextConfiguration("/spring/soap-ws-config.xml")
public class SoapWebServiceTests extends AbstractWebTests {}

@ContextHierarchy(@ContextConfiguration("/spring/rest-ws-config.xml")
public class RestWebServiceTests extends AbstractWebTests {}

The following classes demonstrate the use of named hierarchy levels in order to merge the configuration for specific levels in a context hierarchy. BaseTests defines two levels in the hierarchy, parent and child. ExtendedTests extends BaseTests and instructs the Spring TestContext Framework to merge the context configuration for the child hierarchy level, simply by ensuring that the names declared via the name attribute in @ContextConfiguration are both "child". The result is that three application contexts will be loaded: one for "/app-config.xml", one for "/user-config.xml", and one for {"/user-config.xml", "/order-config.xml"}. As with the previous example, the application context loaded from "/app-config.xml" will be set as the parent context for the contexts loaded from "/user-config.xml" and {"/user-config.xml", "/order-config.xml"}.

@RunWith(SpringRunner.class)
@ContextHierarchy({
    @ContextConfiguration(name = "parent", locations = "/app-config.xml"),
    @ContextConfiguration(name = "child", locations = "/user-config.xml")
})
public class BaseTests {}

@ContextHierarchy(
    @ContextConfiguration(name = "child", locations = "/order-config.xml")
)
public class ExtendedTests extends BaseTests {}

In contrast to the previous example, this example demonstrates how to override the configuration for a given named level in a context hierarchy by setting theinheritLocations flag in @ContextConfiguration to false. Consequently, the application context for ExtendedTests will be loaded only from"/test-user-config.xml" and will have its parent set to the context loaded from "/app-config.xml".

@RunWith(SpringRunner.class)
@ContextHierarchy({
    @ContextConfiguration(name = "parent", locations = "/app-config.xml"),
    @ContextConfiguration(name = "child", locations = "/user-config.xml")
})
public class BaseTests {}

@ContextHierarchy(
    @ContextConfiguration(
        name = "child",
        locations = "/test-user-config.xml",
        inheritLocations = false
))
public class ExtendedTests extends BaseTests {}

If @DirtiesContext is used in a test whose context is configured as part of a context hierarchy, the hierarchyMode flag can be used to control how the context cache is cleared. For further details consult the discussion of @DirtiesContext in Spring Testing Annotations and the @DirtiesContextjavadocs.

11.5.5 Dependency injection of test fixtures

When you use the DependencyInjectionTestExecutionListener — which is configured by default — the dependencies of your test instances are injected from beans in the application context that you configured with @ContextConfiguration. You may use setter injection, field injection, or both, depending on which annotations you choose and whether you place them on setter methods or fields. For consistency with the annotation support introduced in Spring 2.5 and 3.0, you can use Spring’s @Autowired annotation or the @Inject annotation from JSR 330.

The TestContext framework does not instrument the manner in which a test instance is instantiated. Thus the use of @Autowired or @Inject for constructors has no effect for test classes.

Because @Autowired is used to perform autowiring by type, if you have multiple bean definitions of the same type, you cannot rely on this approach for those particular beans. In that case, you can use @Autowired in conjunction with @Qualifier. As of Spring 3.0 you may also choose to use @Inject in conjunction with @Named. Alternatively, if your test class has access to its ApplicationContext, you can perform an explicit lookup by using (for example) a call to applicationContext.getBean("titleRepository").

If you do not want dependency injection applied to your test instances, simply do not annotate fields or setter methods with @Autowired or @Inject. Alternatively, you can disable dependency injection altogether by explicitly configuring your class with @TestExecutionListeners and omitting DependencyInjectionTestExecutionListener.class from the list of listeners.

Consider the scenario of testing a HibernateTitleRepository class, as outlined in the Goals section. The next two code listings demonstrate the use of @Autowiredon fields and setter methods. The application context configuration is presented after all sample code listings.

The dependency injection behavior in the following code listings is not specific to JUnit 4. The same DI techniques can be used in conjunction with any testing framework.The following examples make calls to static assertion methods such as assertNotNull() but without prepending the call with Assert. In such cases, assume that the method was properly imported through an import static declaration that is not shown in the example.

The first code listing shows a JUnit 4 based implementation of the test class that uses @Autowired for field injection.

@RunWith(SpringRunner.class)
// specifies the Spring configuration to load for this test fixture
@ContextConfiguration("repository-config.xml")
public class HibernateTitleRepositoryTests {

    // this instance will be dependency injected by type
    @Autowired
    private HibernateTitleRepository titleRepository;

    @Test
    public void findById() {
        Title title = titleRepository.findById(new Long(10));
        assertNotNull(title);
    }
}

Alternatively, you can configure the class to use @Autowired for setter injection as seen below.

@RunWith(SpringRunner.class)
// specifies the Spring configuration to load for this test fixture
@ContextConfiguration("repository-config.xml")
public class HibernateTitleRepositoryTests {

    // this instance will be dependency injected by type
    private HibernateTitleRepository titleRepository;

    @Autowired
    public void setTitleRepository(HibernateTitleRepository titleRepository) {
        this.titleRepository = titleRepository;
    }

    @Test
    public void findById() {
        Title title = titleRepository.findById(new Long(10));
        assertNotNull(title);
    }
}

The preceding code listings use the same XML context file referenced by the @ContextConfiguration annotation (that is, repository-config.xml), which looks like this:

<?xml version="1.0" encoding="UTF-8"?>
<beans xmlns="http://www.springframework.org/schema/beans"
    xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
    xsi:schemaLocation="http://www.springframework.org/schema/beans
        http://www.springframework.org/schema/beans/spring-beans.xsd">

    <!-- this bean will be injected into the HibernateTitleRepositoryTests class -->
    <bean id="titleRepository" class="com.foo.repository.hibernate.HibernateTitleRepository">
        <property name="sessionFactory" ref="sessionFactory"/>
    </bean>

    <bean id="sessionFactory" class="org.springframework.orm.hibernate5.LocalSessionFactoryBean">
        <!-- configuration elided for brevity -->
    </bean>

</beans>

If you are extending from a Spring-provided test base class that happens to use @Autowired on one of its setter methods, you might have multiple beans of the affected type defined in your application context: for example, multiple DataSource beans. In such a case, you can override the setter method and use the @Qualifier annotation to indicate a specific target bean as follows, but make sure to delegate to the overridden method in the superclass as well.// ... *@Autowired* *@Override* public void setDataSource(**@Qualifier("myDataSource")** DataSource dataSource) { **super**.setDataSource(dataSource); }// ...The specified qualifier value indicates the specific DataSource bean to inject, narrowing the set of type matches to a specific bean. Its value is matched against <qualifier> declarations within the corresponding <bean> definitions. The bean name is used as a fallback qualifier value, so you may effectively also point to a specific bean by name there (as shown above, assuming that "myDataSource" is the bean id).

11.5.6 Testing request and session scoped beans

Request and session scoped beans have been supported by Spring since the early years, and since Spring 3.2 it’s a breeze to test your request-scoped and session-scoped beans by following these steps.

• Ensure that a WebApplicationContext is loaded for your test by annotating your test class with @WebAppConfiguration.
• Inject the mock request or session into your test instance and prepare your test fixture as appropriate.
• Invoke your web component that you retrieved from the configured WebApplicationContext (i.e., via dependency injection).
• Perform assertions against the mocks.

The following code snippet displays the XML configuration for a login use case. Note that the userService bean has a dependency on a request-scoped loginActionbean. Also, the LoginAction is instantiated using SpEL expressions that retrieve the username and password from the current HTTP request. In our test, we will want to configure these request parameters via the mock managed by the TestContext framework.

Request-scoped bean configuration.

<beans>

    <bean id="userService"
            class="com.example.SimpleUserService"
            c:loginAction-ref="loginAction" />

    <bean id="loginAction" class="com.example.LoginAction"
            c:username="{request.getParameter('user')}"
            c:password="{request.getParameter('pswd')}"
            scope="request">
        <aop:scoped-proxy />
    </bean>

</beans>

In RequestScopedBeanTests we inject both the UserService (i.e., the subject under test) and the MockHttpServletRequest into our test instance. Within ourrequestScope() test method we set up our test fixture by setting request parameters in the provided MockHttpServletRequest. When the loginUser() method is invoked on our userService we are assured that the user service has access to the request-scoped loginAction for the current MockHttpServletRequest (i.e., the one we just set parameters in). We can then perform assertions against the results based on the known inputs for the username and password.

Request-scoped bean test.

@RunWith(SpringRunner.class)
@ContextConfiguration
@WebAppConfiguration
public class RequestScopedBeanTests {

    @Autowired UserService userService;
    @Autowired MockHttpServletRequest request;

    @Test
    public void requestScope() {

        request.setParameter("user", "enigma");
        request.setParameter("pswd", "$pr!ng");

        LoginResults results = userService.loginUser();

        // assert results
    }
}

The following code snippet is similar to the one we saw above for a request-scoped bean; however, this time the userService bean has a dependency on a session-scoped userPreferences bean. Note that the UserPreferences bean is instantiated using a SpEL expression that retrieves the theme from the current HTTP session. In our test, we will need to configure a theme in the mock session managed by the TestContext framework.

Session-scoped bean configuration.

<beans>

    <bean id="userService"
            class="com.example.SimpleUserService"
            c:userPreferences-ref="userPreferences" />

    <bean id="userPreferences"
            class="com.example.UserPreferences"
            c:theme="#{session.getAttribute('theme')}"
            scope="session">
        <aop:scoped-proxy />
    </bean>

</beans>

In SessionScopedBeanTests we inject the UserService and the MockHttpSession into our test instance. Within our sessionScope() test method we set up our test fixture by setting the expected "theme" attribute in the provided MockHttpSession. When the processUserPreferences() method is invoked on our userService we are assured that the user service has access to the session-scoped userPreferences for the current MockHttpSession, and we can perform assertions against the results based on the configured theme.

Session-scoped bean test.

@RunWith(SpringRunner.class)
@ContextConfiguration
@WebAppConfiguration
public class SessionScopedBeanTests {

    @Autowired UserService userService;
    @Autowired MockHttpSession session;

    @Test
    public void sessionScope() throws Exception {

        session.setAttribute("theme", "blue");

        Results results = userService.processUserPreferences();

        // assert results
    }
}

11.5.7 Transaction management

In the TestContext framework, transactions are managed by the TransactionalTestExecutionListener which is configured by default, even if you do not explicitly declare @TestExecutionListeners on your test class. To enable support for transactions, however, you must configure a PlatformTransactionManager bean in theApplicationContext that is loaded via @ContextConfiguration semantics (further details are provided below). In addition, you must declare Spring’s @Transactional annotation either at the class or method level for your tests.

Test-managed transactions

Test-managed transactions are transactions that are managed declaratively via the TransactionalTestExecutionListener or programmatically via TestTransaction (see below). Such transactions should not be confused with Spring-managed transactions (i.e., those managed directly by Spring within the ApplicationContext loaded for tests) or application-managed transactions (i.e., those managed programmatically within application code that is invoked via tests). Spring-managed and application-managed transactions will typically participate in test-managed transactions; however, caution should be taken if Spring-managed or application-managed transactions are configured with any propagation type other than REQUIRED or SUPPORTS (see the discussion on transaction propagation for details).

Enabling and disabling transactions

Annotating a test method with @Transactional causes the test to be run within a transaction that will, by default, be automatically rolled back after completion of the test. If a test class is annotated with @Transactional, each test method within that class hierarchy will be run within a transaction. Test methods that are not annotated with @Transactional (at the class or method level) will not be run within a transaction. Furthermore, tests that are annotated with @Transactional but have thepropagation type set to NOT_SUPPORTED will not be run within a transaction.

Note that AbstractTransactionalJUnit4SpringContextTests and AbstractTransactionalTestNGSpringContextTests are preconfigured for transactional support at the class level.

The following example demonstrates a common scenario for writing an integration test for a Hibernate-based UserRepository. As explained in the section called “Transaction rollback and commit behavior”, there is no need to clean up the database after the createUser() method is executed since any changes made to the database will be automatically rolled back by the TransactionalTestExecutionListener. See Section 11.7, “PetClinic Example” for an additional example.

@RunWith(SpringRunner.class)
@ContextConfiguration(classes = TestConfig.class)
@Transactional
public class HibernateUserRepositoryTests {

    @Autowired
    HibernateUserRepository repository;

    @Autowired
    SessionFactory sessionFactory;

    JdbcTemplate jdbcTemplate;

    @Autowired
    public void setDataSource(DataSource dataSource) {
        this.jdbcTemplate = new JdbcTemplate(dataSource);
    }

    @Test
    public void createUser() {
        // track initial state in test database:
        final int count = countRowsInTable("user");

        User user = new User(...);
        repository.save(user);

        // Manual flush is required to avoid false positive in test
        sessionFactory.getCurrentSession().flush();
        assertNumUsers(count + 1);
    }

    protected int countRowsInTable(String tableName) {
        return JdbcTestUtils.countRowsInTable(this.jdbcTemplate, tableName);
    }

    protected void assertNumUsers(int expected) {
        assertEquals("Number of rows in the [user] table.", expected, countRowsInTable("user"));
    }
}

Transaction rollback and commit behavior

By default, test transactions will be automatically rolled back after completion of the test; however, transactional commit and rollback behavior can be configured declaratively via the @Commit and @Rollback annotations. See the corresponding entries in the annotation support section for further details.

Programmatic transaction management

Since Spring Framework 4.1, it is possible to interact with test-managed transactions programmatically via the static methods in TestTransaction. For example,TestTransaction may be used within test methods, before methods, and after methods to start or end the current test-managed transaction or to configure the current test-managed transaction for rollback or commit. Support for TestTransaction is automatically available whenever the TransactionalTestExecutionListener is enabled.

The following example demonstrates some of the features of TestTransaction. Consult the javadocs for TestTransaction for further details.

@ContextConfiguration(classes = TestConfig.class)
public class ProgrammaticTransactionManagementTests extends
        AbstractTransactionalJUnit4SpringContextTests {

    @Test
    public void transactionalTest() {
        // assert initial state in test database:
        assertNumUsers(2);

        deleteFromTables("user");

        // changes to the database will be committed!
        TestTransaction.flagForCommit();
        TestTransaction.end();
        assertFalse(TestTransaction.isActive());
        assertNumUsers(0);

        TestTransaction.start();
        // perform other actions against the database that will
        // be automatically rolled back after the test completes...
    }

    protected void assertNumUsers(int expected) {
        assertEquals("Number of rows in the [user] table.", expected, countRowsInTable("user"));
    }
}

Executing code outside of a transaction

Occasionally you need to execute certain code before or after a transactional test method but outside the transactional context — for example, to verify the initial database state prior to execution of your test or to verify expected transactional commit behavior after test execution (if the test was configured to commit the transaction). TransactionalTestExecutionListener supports the @BeforeTransaction and @AfterTransaction annotations exactly for such scenarios. Simply annotate any void method in a test class or any void default method in a test interface with one of these annotations, and the TransactionalTestExecutionListener ensures that your before transaction method or after transaction method is executed at the appropriate time.

Any before methods (such as methods annotated with JUnit 4’s @Before) and any after methods (such as methods annotated with JUnit 4’s @After) are executed within a transaction. In addition, methods annotated with @BeforeTransaction or @AfterTransaction are naturally not executed for test methods that are not configured to run within a transaction.

Configuring a transaction manager

TransactionalTestExecutionListener expects a PlatformTransactionManager bean to be defined in the Spring ApplicationContext for the test. In case there are multiple instances of PlatformTransactionManager within the test’s ApplicationContext, a qualifier may be declared via @Transactional("myTxMgr")or @Transactional(transactionManager = "myTxMgr"), or TransactionManagementConfigurer can be implemented by an @Configuration class. Consult the javadocs for TestContextTransactionUtils.retrieveTransactionManager() for details on the algorithm used to look up a transaction manager in the test’s ApplicationContext.

Demonstration of all transaction-related annotations

The following JUnit 4 based example displays a fictitious integration testing scenario highlighting all transaction-related annotations. The example is not intended to demonstrate best practices but rather to demonstrate how these annotations can be used. Consult the annotation support section for further information and configuration examples. Transaction management for @Sql contains an additional example using @Sql for declarative SQL script execution with default transaction rollback semantics.

@RunWith(SpringRunner.class)
@ContextConfiguration
@Transactional(transactionManager = "txMgr")
@Commit
public class FictitiousTransactionalTest {

    @BeforeTransaction
    void verifyInitialDatabaseState() {
        // logic to verify the initial state before a transaction is started
    }

    @Before
    public void setUpTestDataWithinTransaction() {
        // set up test data within the transaction
    }

    @Test
    // overrides the class-level @Commit setting
    @Rollback
    public void modifyDatabaseWithinTransaction() {
        // logic which uses the test data and modifies database state
    }

    @After
    public void tearDownWithinTransaction() {
        // execute "tear down" logic within the transaction
    }

    @AfterTransaction
    void verifyFinalDatabaseState() {
        // logic to verify the final state after transaction has rolled back
    }

}

When you test application code that manipulates the state of a Hibernate session or JPA persistence context, make sure to flush the underlying unit of work within test methods that execute that code. Failing to flush the underlying unit of work can produce false positives: your test may pass, but the same code throws an exception in a live, production environment. In the following Hibernate-based example test case, one method demonstrates a false positive, and the other method correctly exposes the results of flushing the session. Note that this applies to any ORM frameworks that maintain an in-memory unit of work.// ...*@Autowired*SessionFactory sessionFactory;*@Transactional**@Test* // no expected exception!public void falsePositive() { updateEntityInHibernateSession(); // False positive: an exception will be thrown once the Hibernate // Session is finally flushed (i.e., in production code)}*@Transactional**@Test(expected = ...)*public void updateWithSessionFlush() { updateEntityInHibernateSession(); // Manual flush is required to avoid false positive in test sessionFactory.getCurrentSession().flush();}// ...Or for JPA:// ...*@PersistenceContext*EntityManager entityManager;*@Transactional**@Test* // no expected exception!public void falsePositive() { updateEntityInJpaPersistenceContext(); // False positive: an exception will be thrown once the JPA // EntityManager is finally flushed (i.e., in production code)}*@Transactional**@Test(expected = ...)*public void updateWithEntityManagerFlush() { updateEntityInJpaPersistenceContext(); // Manual flush is required to avoid false positive in test entityManager.flush();}// ...

11.5.8 Executing SQL scripts

When writing integration tests against a relational database, it is often beneficial to execute SQL scripts to modify the database schema or insert test data into tables. The spring-jdbc module provides support for initializing an embedded or existing database by executing SQL scripts when the Spring ApplicationContext is loaded. See Section 15.8, “Embedded database support” and Section 15.8.5, “Testing data access logic with an embedded database” for details.

Although it is very useful to initialize a database for testing once when the ApplicationContext is loaded, sometimes it is essential to be able to modify the database during integration tests. The following sections explain how to execute SQL scripts programmatically and declaratively during integration tests.

Executing SQL scripts programmatically

Spring provides the following options for executing SQL scripts programmatically within integration test methods.

• org.springframework.jdbc.datasource.init.ScriptUtils
• org.springframework.jdbc.datasource.init.ResourceDatabasePopulator
• org.springframework.test.context.junit4.AbstractTransactionalJUnit4SpringContextTests
• org.springframework.test.context.testng.AbstractTransactionalTestNGSpringContextTests

ScriptUtils provides a collection of static utility methods for working with SQL scripts and is mainly intended for internal use within the framework. However, if you require full control over how SQL scripts are parsed and executed, ScriptUtils may suit your needs better than some of the other alternatives described below. Consult the javadocs for individual methods in ScriptUtils for further details.

ResourceDatabasePopulator provides a simple object-based API for programmatically populating, initializing, or cleaning up a database using SQL scripts defined in external resources. ResourceDatabasePopulator provides options for configuring the character encoding, statement separator, comment delimiters, and error handling flags used when parsing and executing the scripts, and each of the configuration options has a reasonable default value. Consult the javadocs for details on default values. To execute the scripts configured in a ResourceDatabasePopulator, you can invoke either the populate(Connection) method to execute the populator against a java.sql.Connection or the execute(DataSource) method to execute the populator against a javax.sql.DataSource. The following example specifies SQL scripts for a test schema and test data, sets the statement separator to "@@", and then executes the scripts against a DataSource.

@Test
public void databaseTest {
    ResourceDatabasePopulator populator = new ResourceDatabasePopulator();
    populator.addScripts(
        new ClassPathResource("test-schema.sql"),
        new ClassPathResource("test-data.sql"));
    populator.setSeparator("@@");
    populator.execute(this.dataSource);
    // execute code that uses the test schema and data
}

Note that ResourceDatabasePopulator internally delegates to ScriptUtils for parsing and executing SQL scripts. Similarly, the executeSqlScript(..) methods in AbstractTransactionalJUnit4SpringContextTests and AbstractTransactionalTestNGSpringContextTests internally use a ResourceDatabasePopulator for executing SQL scripts. Consult the javadocs for the various executeSqlScript(..) methods for further details.

Executing SQL scripts declaratively with @Sql

In addition to the aforementioned mechanisms for executing SQL scripts programmatically, SQL scripts can also be configured declaratively in the Spring TestContext Framework. Specifically, the @Sql annotation can be declared on a test class or test method to configure the resource paths to SQL scripts that should be executed against a given database either before or after an integration test method. Note that method-level declarations override class-level declarations and that support for@Sql is provided by the SqlScriptsTestExecutionListener which is enabled by default.

Path resource semantics

Each path will be interpreted as a Spring Resource. A plain path — for example, "schema.sql" — will be treated as a classpath resource that is relative to the package in which the test class is defined. A path starting with a slash will be treated as an absolute classpath resource, for example: "/org/example/schema.sql". A path which references a URL (e.g., a path prefixed with classpath:, file:, http:, etc.) will be loaded using the specified resource protocol.

The following example demonstrates how to use @Sql at the class level and at the method level within a JUnit 4 based integration test class.

@RunWith(SpringRunner.class)
@ContextConfiguration
@Sql("/test-schema.sql")
public class DatabaseTests {

    @Test
    public void emptySchemaTest {
        // execute code that uses the test schema without any test data
    }

    @Test
    @Sql({"/test-schema.sql", "/test-user-data.sql"})
    public void userTest {
        // execute code that uses the test schema and test data
    }
}

Default script detection

If no SQL scripts are specified, an attempt will be made to detect a default script depending on where @Sql is declared. If a default cannot be detected, anIllegalStateException will be thrown.

• class-level declaration: if the annotated test class is com.example.MyTest, the corresponding default script is "classpath:com/example/MyTest.sql".
• method-level declaration: if the annotated test method is named testMethod() and is defined in the class com.example.MyTest, the corresponding default script is "classpath:com/example/MyTest.testMethod.sql".

Declaring multiple @Sql sets

If multiple sets of SQL scripts need to be configured for a given test class or test method but with different syntax configuration, different error handling rules, or different execution phases per set, it is possible to declare multiple instances of @Sql. With Java 8, @Sql can be used as a repeatable annotation. Otherwise, the @SqlGroupannotation can be used as an explicit container for declaring multiple instances of @Sql.

The following example demonstrates the use of @Sql as a repeatable annotation using Java 8. In this scenario the test-schema.sql script uses a different syntax for single-line comments.

@Test
@Sql(scripts = "/test-schema.sql", config = @SqlConfig(commentPrefix = "`"))
@Sql("/test-user-data.sql")
public void userTest {
    // execute code that uses the test schema and test data
}

The following example is identical to the above except that the @Sql declarations are grouped together within @SqlGroup for compatibility with Java 6 and Java 7.

@Test
@SqlGroup({
    @Sql(scripts = "/test-schema.sql", config = @SqlConfig(commentPrefix = "`")),
    @Sql("/test-user-data.sql")
)}
public void userTest {
    // execute code that uses the test schema and test data
}

Script execution phases

By default, SQL scripts will be executed before the corresponding test method. However, if a particular set of scripts needs to be executed after the test method — for example, to clean up database state — the executionPhase attribute in @Sql can be used as seen in the following example. Note that ISOLATED and AFTER_TEST_METHOD are statically imported from Sql.TransactionMode and Sql.ExecutionPhase respectively.

@Test
@Sql(
    scripts = "create-test-data.sql",
    config = @SqlConfig(transactionMode = ISOLATED)
)
@Sql(
    scripts = "delete-test-data.sql",
    config = @SqlConfig(transactionMode = ISOLATED),
    executionPhase = AFTER_TEST_METHOD
)
public void userTest {
    // execute code that needs the test data to be committed
    // to the database outside of the test's transaction
}

Script configuration with @SqlConfig

Configuration for script parsing and error handling can be configured via the @SqlConfig annotation. When declared as a class-level annotation on an integration test class, @SqlConfig serves as global configuration for all SQL scripts within the test class hierarchy. When declared directly via the config attribute of the @Sqlannotation, @SqlConfig serves as local configuration for the SQL scripts declared within the enclosing @Sql annotation. Every attribute in @SqlConfig has an implicit default value which is documented in the javadocs of the corresponding attribute. Due to the rules defined for annotation attributes in the Java Language Specification, it is unfortunately not possible to assign a value of null to an annotation attribute. Thus, in order to support overrides of inherited global configuration, @SqlConfigattributes have an explicit default value of either "" for Strings or DEFAULT for Enums. This approach allows local declarations of @SqlConfig to selectively override individual attributes from global declarations of @SqlConfig by providing a value other than "" or DEFAULT. Global @SqlConfig attributes are inherited whenever local @SqlConfig attributes do not supply an explicit value other than "" or DEFAULT. Explicit local configuration therefore overrides global configuration.

The configuration options provided by @Sql and @SqlConfig are equivalent to those supported by ScriptUtils and ResourceDatabasePopulator but are a superset of those provided by the <jdbc:initialize-database/> XML namespace element. Consult the javadocs of individual attributes in @Sql and @SqlConfigfor details.

Transaction management for @Sql

By default, the SqlScriptsTestExecutionListener will infer the desired transaction semantics for scripts configured via @Sql. Specifically, SQL scripts will be executed without a transaction, within an existing Spring-managed transaction — for example, a transaction managed by the TransactionalTestExecutionListenerfor a test annotated with @Transactional — or within an isolated transaction, depending on the configured value of the transactionMode attribute in @SqlConfigand the presence of a PlatformTransactionManager in the test’s ApplicationContext. As a bare minimum however, a javax.sql.DataSource must be present in the test’s ApplicationContext.

If the algorithms used by SqlScriptsTestExecutionListener to detect a DataSource and PlatformTransactionManager and infer the transaction semantics do not suit your needs, you may specify explicit names via the dataSource and transactionManager attributes of @SqlConfig. Furthermore, the transaction propagation behavior can be controlled via the transactionMode attribute of @SqlConfig — for example, if scripts should be executed in an isolated transaction. Although a thorough discussion of all supported options for transaction management with @Sql is beyond the scope of this reference manual, the javadocs for @SqlConfig and SqlScriptsTestExecutionListener provide detailed information, and the following example demonstrates a typical testing scenario using JUnit 4 and transactional tests with @Sql. Note that there is no need to clean up the database after the usersTest() method is executed since any changes made to the database (either within the test method or within the /test-data.sql script) will be automatically rolled back by the TransactionalTestExecutionListener (seetransaction management for details).

@RunWith(SpringRunner.class)
@ContextConfiguration(classes = TestDatabaseConfig.class)
@Transactional
public class TransactionalSqlScriptsTests {

    protected JdbcTemplate jdbcTemplate;

    @Autowired
    public void setDataSource(DataSource dataSource) {
        this.jdbcTemplate = new JdbcTemplate(dataSource);
    }

    @Test
    @Sql("/test-data.sql")
    public void usersTest() {
        // verify state in test database:
        assertNumUsers(2);
        // execute code that uses the test data...
    }

    protected int countRowsInTable(String tableName) {
        return JdbcTestUtils.countRowsInTable(this.jdbcTemplate, tableName);
    }

    protected void assertNumUsers(int expected) {
        assertEquals("Number of rows in the [user] table.", expected, countRowsInTable("user"));
    }
}

11.5.9 Parallel test execution

Spring Framework 5.0 introduces basic support for executing tests in parallel within a single JVM when using the Spring TestContext Framework. In general this means that most test classes or test methods can be executed in parallel without any changes to test code or configuration.

For details on how to set up parallel test execution, consult the documentation for your testing framework, build tool, or IDE.

Keep in mind that the introduction of concurrency into your test suite can result in unexpected side effects, strange runtime behavior, and tests that only fail intermittently or seemingly randomly. The Spring Team therefore provides the following general guidelines for when not to execute tests in parallel.

Do not execute tests in parallel if:

• Tests make use of Spring’s @DirtiesContext support.
• Tests make use of JUnit 4’s @FixMethodOrder support or any testing framework feature that is designed to ensure that test methods execute in a particular order. Note, however, that this does not apply if entire test classes are executed in parallel.
• Tests change the state of shared services or systems such as a database, message broker, filesystem, etc. This applies to both in-memory and external systems.

If parallel test execution fails with an exception stating that the ApplicationContext for the current test is no longer active, this typically means that theApplicationContext was removed from the ContextCache in a different thread.This may be due to the use of @DirtiesContext or due to automatic eviction from the ContextCache. If @DirtiesContext is the culprit, you will either need to find a way to avoid using @DirtiesContext or exclude such tests from parallel execution. If the maximum size of the ContextCache has been exceeded, you can increase the maximum size of the cache. See the discussion on context caching for details.

Parallel test execution in the Spring TestContext Framework is only possible if the underlying TestContext implementation provides a copy constructor as explained in the javadocs for TestContext. The DefaultTestContext used in Spring provides such a constructor; however, if you use a third-party library that provides a custom TestContext implementation, you will need to verify if it is suitable for parallel test execution.

11.5.10 TestContext Framework support classes

Spring JUnit 4 Runner

The Spring TestContext Framework offers full integration with JUnit 4 through a custom runner (supported on JUnit 4.12 or higher). By annotating test classes with@RunWith(SpringJUnit4ClassRunner.class) or the shorter @RunWith(SpringRunner.class) variant, developers can implement standard JUnit 4 based unit and integration tests and simultaneously reap the benefits of the TestContext framework such as support for loading application contexts, dependency injection of test instances, transactional test method execution, and so on. If you would like to use the Spring TestContext Framework with an alternative runner such as JUnit 4’s Parameterized or third-party runners such as the MockitoJUnitRunner, you may optionally use Spring’s support for JUnit rules instead.

The following code listing displays the minimal requirements for configuring a test class to run with the custom Spring Runner. @TestExecutionListeners is configured with an empty list in order to disable the default listeners, which otherwise would require an ApplicationContext to be configured through @ContextConfiguration.

@RunWith(SpringRunner.class)
@TestExecutionListeners({})
public class SimpleTest {

   @Test
   public void testMethod() {
      // execute test logic...
   }
}

Spring JUnit 4 Rules

The org.springframework.test.context.junit4.rules package provides the following JUnit 4 rules (supported on JUnit 4.12 or higher).

• SpringClassRule
• SpringMethodRule

SpringClassRule is a JUnit TestRule that supports class-level features of the Spring TestContext Framework; whereas, SpringMethodRule is a JUnit MethodRulethat supports instance-level and method-level features of the Spring TestContext Framework.

In contrast to the SpringRunner, Spring’s rule-based JUnit support has the advantage that it is independent of any org.junit.runner.Runner implementation and can therefore be combined with existing alternative runners like JUnit 4’s Parameterized or third-party runners such as the MockitoJUnitRunner.

In order to support the full functionality of the TestContext framework, a SpringClassRule must be combined with a SpringMethodRule. The following example demonstrates the proper way to declare these rules in an integration test.

// Optionally specify a non-Spring Runner via @RunWith(...)
@ContextConfiguration
public class IntegrationTest {

   @ClassRule
   public static final SpringClassRule SPRING_CLASS_RULE = new SpringClassRule();

   @Rule
   public final SpringMethodRule springMethodRule = new SpringMethodRule();

   @Test
   public void testMethod() {
      // execute test logic...
   }
}

JUnit 4 support classes

The org.springframework.test.context.junit4 package provides the following support classes for JUnit 4 based test cases (supported on JUnit 4.12 or higher).

• AbstractJUnit4SpringContextTests
• AbstractTransactionalJUnit4SpringContextTests

AbstractJUnit4SpringContextTests is an abstract base test class that integrates the Spring TestContext Framework with explicit ApplicationContext testing support in a JUnit 4 environment. When you extend AbstractJUnit4SpringContextTests, you can access a protected applicationContext instance variable that can be used to perform explicit bean lookups or to test the state of the context as a whole.

AbstractTransactionalJUnit4SpringContextTests is an abstract transactional extension of AbstractJUnit4SpringContextTests that adds some convenience functionality for JDBC access. This class expects a javax.sql.DataSource bean and a PlatformTransactionManager bean to be defined in the ApplicationContext. When you extend AbstractTransactionalJUnit4SpringContextTests you can access a protected jdbcTemplate instance variable that can be used to execute SQL statements to query the database. Such queries can be used to confirm database state both prior to and after execution of database-related application code, and Spring ensures that such queries run in the scope of the same transaction as the application code. When used in conjunction with an ORM tool, be sure to avoid false positives. As mentioned in Section 11.3, “JDBC Testing Support”, AbstractTransactionalJUnit4SpringContextTests also provides convenience methods which delegate to methods in JdbcTestUtils using the aforementioned jdbcTemplate. Furthermore, AbstractTransactionalJUnit4SpringContextTests provides an executeSqlScript(..) method for executing SQL scripts against the configured DataSource.

These classes are a convenience for extension. If you do not want your test classes to be tied to a Spring-specific class hierarchy, you can configure your own custom test classes by using @RunWith(SpringRunner.class) or Spring’s JUnit rules.

TestNG support classes

The org.springframework.test.context.testng package provides the following support classes for TestNG based test cases.

• AbstractTestNGSpringContextTests
• AbstractTransactionalTestNGSpringContextTests

AbstractTestNGSpringContextTests is an abstract base test class that integrates the Spring TestContext Framework with explicit ApplicationContext testing support in a TestNG environment. When you extend AbstractTestNGSpringContextTests, you can access a protected applicationContext instance variable that can be used to perform explicit bean lookups or to test the state of the context as a whole.

AbstractTransactionalTestNGSpringContextTests is an abstract transactional extension of AbstractTestNGSpringContextTests that adds some convenience functionality for JDBC access. This class expects a javax.sql.DataSource bean and a PlatformTransactionManager bean to be defined in the ApplicationContext. When you extend AbstractTransactionalTestNGSpringContextTests you can access a protected jdbcTemplate instance variable that can be used to execute SQL statements to query the database. Such queries can be used to confirm database state both prior to and after execution of database-related application code, and Spring ensures that such queries run in the scope of the same transaction as the application code. When used in conjunction with an ORM tool, be sure to avoid false positives. As mentioned in Section 11.3, “JDBC Testing Support”, AbstractTransactionalTestNGSpringContextTests also provides convenience methods which delegate to methods in JdbcTestUtils using the aforementioned jdbcTemplate. Furthermore, AbstractTransactionalTestNGSpringContextTests provides an executeSqlScript(..) method for executing SQL scripts against the configured DataSource.

These classes are a convenience for extension. If you do not want your test classes to be tied to a Spring-specific class hierarchy, you can configure your own custom test classes by using @ContextConfiguration, @TestExecutionListeners, and so on, and by manually instrumenting your test class with a TestContextManager. See the source code of AbstractTestNGSpringContextTests for an example of how to instrument your test class.