Testing

@BootstrapWith is a class-level annotation that you can use to configure how the Spring TestContext Framework is bootstrapped. Specifically, you can use @BootstrapWith to specify a custom TestContextBootstrapper. See the Bootstrapping the TestContext framework section for further details.

@ContextConfiguration defines class-level metadata that is used to determine how to load and configure an ApplicationContext for integration tests. Specifically, @ContextConfiguration declares the application context resource locations or the annotated classes used to load the context.

Resource locations are typically XML configuration files or Groovy scripts located in the classpath, while annotated classes are typically @Configuration classes. However, resource locations can also refer to files and scripts in the file system, and annotated classes can be component classes, and so on.

The following example shows a @ContextConfiguration annotation that refers to an XML file:

The following example shows a @ContextConfiguration annotation that refers to a class:

As an alternative or in addition to declaring resource locations or annotated classes, you can use @ContextConfiguration to declare ApplicationContextInitializer classes. The following example shows such a case:

You can optionally use @ContextConfiguration to declare the ContextLoader strategy as well. Note, however, that you typically do not need to explicitly configure the loader, since the default loader supports initializers and either resource locations or annotated classes.

The following example uses both a location and a loader:

See Context Management and the @ContextConfiguration javadocs for further details.

@WebAppConfiguration is a class-level annotation that you can use to declare that the ApplicationContext loaded for an integration test should be a WebApplicationContext. The mere presence of @WebAppConfiguration on a test class ensures that a WebApplicationContext is loaded for the test, using the default value of "file:src/main/webapp" for the path to the root of the web application (that is, the resource base path). The resource base path is used behind the scenes to create a MockServletContext, which serves as the ServletContext for the test’s WebApplicationContext.

The following example shows how to use the @WebAppConfiguration annotation:

To override the default, you can specify a different base resource path by using the implicit value attribute. Both classpath: and file: resource prefixes are supported. If no resource prefix is supplied, the path is assumed to be a file system resource. The following example shows how to specify a classpath resource:

Note that @WebAppConfiguration must be used in conjunction with @ContextConfiguration, either within a single test class or within a test class hierarchy. See the @WebAppConfiguration Javadoc for further details.

@ContextHierarchy is a class-level annotation that is used to define a hierarchy of ApplicationContext instances for integration tests. @ContextHierarchy should be declared with a list of one or more @ContextConfiguration instances, each of which defines a level in the context hierarchy. The following examples demonstrate the use of @ContextHierarchy within a single test class (@ContextHierarchy can also be used within a test class hierarchy):

If you need to merge or override the configuration for a given level of the context hierarchy within a test class hierarchy, you must explicitly name that level by supplying the same value to the name attribute in @ContextConfiguration at each corresponding level in the class hierarchy. See Context Hierarchies and the @ContextHierarchy Javadoc for further examples.

@ActiveProfiles is a class-level annotation that is used to declare which bean definition profiles should be active when loading an ApplicationContext for an integration test.

The following example indicates that the dev profile should be active:

The following example indicates that both the dev and the integration profiles should be active:

See Context Configuration with Environment Profiles and the @ActiveProfiles Javadoc for examples and further details.

@TestPropertySource is a class-level annotation that you can use to configure the locations of properties files and inlined properties to be added to the set of PropertySources in the Environment for an ApplicationContext loaded for an integration test.

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 through @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.

The following example demonstrates how to declare a properties file from the classpath:

The following example demonstrates how to declare inlined properties:

@DirtiesContext indicates that the underlying Spring ApplicationContext has been dirtied during the execution of a test (that is, the test modified or corrupted it in some manner — for example, by changing the state of a singleton bean) and should be closed. When an application context is marked as dirty, it is removed from the testing framework’s cache and closed. As a consequence, the underlying Spring container is rebuilt for any subsequent test that requires a context with the same configuration metadata.

You can use @DirtiesContext as both a class-level and a method-level annotation within the same class or class hierarchy. In such scenarios, the ApplicationContext is marked as dirty before or after any such annotated method as well as before or after the current test class, depending on the configured methodMode and classMode.

The following examples explain when the context would be dirtied for various configuration scenarios:

If you use @DirtiesContext in a test whose context is configured as part of a context hierarchy with @ContextHierarchy, you can use the hierarchyMode flag to control how the context cache is cleared. By default, an exhaustive algorithm is used to clear the context cache, including not only the current level but also all other context hierarchies that share an ancestor context common to the current test. All ApplicationContext instances that reside in a sub-hierarchy of the common ancestor context are removed from the context cache and closed. If the exhaustive algorithm is overkill for a particular use case, you can specify the simpler current level algorithm, as the following example shows.

For further details regarding the EXHAUSTIVE and CURRENT_LEVEL algorithms, see the DirtiesContext.HierarchyMode Javadoc.

@TestExecutionListeners defines class-level metadata for configuring the TestExecutionListener implementations that should be registered with the TestContextManager. Typically, @TestExecutionListeners is used in conjunction with @ContextConfiguration.

The following example shows how to register two TestExecutionListener implementations:

By default, @TestExecutionListeners supports inherited listeners. See the Javadoc for an example and further details.

@Commit indicates that the transaction for a transactional test method should be committed after the test method has completed. You can use @Commit as a direct replacement for @Rollback(false) to more explicitly convey the intent of the code. Analogous to @Rollback, @Commit can also be declared as a class-level or method-level annotation.

The following example shows how to use the @Commit annotation:

@Rollback indicates whether the transaction for a transactional test method should be rolled back after the test method has completed. If true, the transaction is rolled back. Otherwise, the transaction is committed (see also @Commit). Rollback for integration tests in the Spring TestContext Framework defaults to true even if @Rollback is not explicitly declared.

When declared as a class-level annotation, @Rollback defines the default rollback semantics for all test methods within the test class hierarchy. When declared as a method-level annotation, @Rollback defines rollback semantics for the specific test method, potentially overriding class-level @Rollback or @Commit semantics.

The following example causes a test method’s result to not be rolled back (that is, the result is committed to the database):

@BeforeTransaction indicates that the annotated void method should be run before a transaction is started, for test methods that have been configured to run within a transaction by using Spring’s @Transactional annotation. As of Spring Framework 4.3, @BeforeTransaction methods are not required to be public and may be declared on Java 8-based interface default methods.

The following example shows how to use the @BeforeTransaction annotation:

@AfterTransaction indicates that the annotated void method should be run after a transaction is ended, for test methods that have been configured to run within a transaction by using Spring’s @Transactional annotation. As of Spring Framework 4.3, @AfterTransaction methods are not required to be public and may be declared on Java 8-based interface default methods.

@Sql is used to annotate a test class or test method to configure SQL scripts to be run against a given database during integration tests. The following example shows how to use it:

See Executing SQL scripts declaratively with @Sql for further details.

@SqlConfig defines metadata that is used to determine how to parse and run SQL scripts configured with the @Sql annotation. The following example shows how to use it:

@SqlGroup is a container annotation that aggregates several @Sql annotations. You can use @SqlGroup natively to declare several nested @Sql annotations, or you can use it in conjunction with Java 8’s support for repeatable annotations, where @Sql can be declared several times on the same class or method, implicitly generating this container annotation. The following example shows how to declare an SQL group:

@IfProfileValue indicates that the annotated test is enabled for a specific testing environment. If the configured ProfileValueSource returns a matching value for the provided name, the test is enabled. Otherwise, the test is disabled and, effectively, ignored.

You can apply @IfProfileValue at the class level, the method level, or both. Class-level usage of @IfProfileValue takes precedence over method-level usage for any methods within that class or its subclasses. Specifically, a test is enabled if it is enabled both at the class level and at the method level. The absence of @IfProfileValue means the test is implicitly enabled. This is analogous to the semantics of JUnit 4’s @Ignore annotation, except that the presence of @Ignore always disables a test.

The following example shows a test that has an @IfProfileValue annotation:

Alternatively, you can configure @IfProfileValue with a list of values (with OR semantics) to achieve TestNG-like support for test groups in a JUnit 4 environment. Consider the following example:

@ProfileValueSourceConfiguration is a class-level annotation that specifies what type of ProfileValueSource to use when retrieving profile values configured through the @IfProfileValue annotation. If @ProfileValueSourceConfiguration is not declared for a test, SystemProfileValueSource is used by default. The following example shows how to use @ProfileValueSourceConfiguration:

@Timed indicates that the annotated test method must finish execution in a specified time period (in milliseconds). If the text execution time exceeds the specified time period, the test fails.

The time period includes running the test method itself, any repetitions of the test (see @Repeat), as well as any setting up or tearing down of the test fixture. The following example shows how to use it:

Spring’s @Timed annotation has different semantics than JUnit 4’s @Test(timeout=…​) support. Specifically, due to the manner in which JUnit 4 handles test execution timeouts (that is, by executing the test method in a separate Thread), @Test(timeout=…​) preemptively fails the test if the test takes too long. Spring’s @Timed, on the other hand, does not preemptively fail the test but rather waits for the test to complete before failing.

@Repeat indicates that the annotated test method must be run repeatedly. The number of times that the test method is to be executed is specified in the annotation.

The scope of execution to be repeated includes execution of the test method itself as well as any setting up or tearing down of the test fixture. The following example shows how to use the @Repeat annotation:

@SpringJUnitConfig is a composed annotation that combines @ExtendWith(SpringExtension.class) from JUnit Jupiter with @ContextConfiguration from the Spring TestContext Framework. It can be used at the class level as a drop-in replacement for @ContextConfiguration. With regard to configuration options, the only difference between @ContextConfiguration and @SpringJUnitConfig is that annotated classes may be declared with the value attribute in @SpringJUnitConfig.

The following example shows how to use the @SpringJUnitConfig annotation to specify a configuration class:

The following example shows how to use the @SpringJUnitConfig annotation to specify the location of a configuration file:

See Context Management as well as the Javadoc for @SpringJUnitConfig and @ContextConfiguration for further details.

@SpringJUnitWebConfig is a composed annotation that combines @ExtendWith(SpringExtension.class) from JUnit Jupiter with @ContextConfiguration and @WebAppConfiguration from the Spring TestContext Framework. You can use it at the class level as a drop-in replacement for @ContextConfiguration and @WebAppConfiguration. With regard to configuration options, the only difference between @ContextConfiguration and @SpringJUnitWebConfig is that you can declare annotated classes bu using the value attribute in @SpringJUnitWebConfig. In addition, you can override the value attribute from @WebAppConfiguration only by using the resourcePath attribute in @SpringJUnitWebConfig.

The following example shows how to use the @SpringJUnitWebConfig annotation to specify a configuration class:

The following example shows how to use the @SpringJUnitWebConfig annotation to specify a the location of a configuration file:

See Context Management as well as the Javadoc for @SpringJUnitWebConfig, @ContextConfiguration, and @WebAppConfiguration for further details.

@EnabledIf is used to signal that the annotated JUnit Jupiter test class or test method is enabled and should be run if the supplied expression evaluates to true. Specifically, if the expression evaluates to Boolean.TRUE or a String equal to true (ignoring case), the test is enabled. When applied at the class level, all test methods within that class are automatically enabled by default as well.

Expressions can be any of the following:

Note, however, that a text literal that is not the result of dynamic resolution of a property placeholder is of zero practical value, since @EnabledIf("false") is equivalent to @Disabled and @EnabledIf("true") is logically meaningless.

You can use @EnabledIf as a meta-annotation to create custom composed annotations. For example, you can create a custom @EnabledOnMac annotation as follows:

@DisabledIf is used to signal that the annotated JUnit Jupiter test class or test method is disabled and should not be executed if the supplied expression evaluates to true. Specifically, if the expression evaluates to Boolean.TRUE or a String equal to true (ignoring case), the test is disabled. When applied at the class level, all test methods within that class are automatically disabled as well.

Expressions can be any of the following:

Note, however, that a text literal that is not the result of dynamic resolution of a property placeholder is of zero practical value, since @DisabledIf("true") is equivalent to @Disabled and @DisabledIf("false") is logically meaningless.

You can use @DisabledIf as a meta-annotation to create custom composed annotations. For example, you can create a custom @DisabledOnMac annotation as follows:

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 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:

TestExecutionListener defines the API for reacting to test-execution events published by the TestContextManager with which the listener is registered. See TestExecutionListener Configuration.

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. You should implement SmartContextLoader instead of this interface 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:

You can register custom TestExecutionListener implementations for a test class and its subclasses by using the @TestExecutionListeners annotation. See annotation support and the Javadoc for @TestExecutionListeners for details and examples.

Registering custom TestExecutionListener implementations by using @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 through support for automatic discovery of default TestExecutionListener implementations through the SpringFactoriesLoader mechanism.

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

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

If a custom TestExecutionListener is registered via @TestExecutionListeners, the default listeners are not 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:

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 TestExecutionListener implementations by using the aforementioned automatic discovery mechanism.

To avoid having to be aware of and re-declare all default listeners, you can set the mergeMode attribute of @TestExecutionListeners to MergeMode.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 Ordering TestExecutionListener Implementations. 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 are 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 the ServletTestExecutionListener (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:

To load an ApplicationContext for your tests by using XML configuration files, annotate your test class with @ContextConfiguration and configure the locations attribute with an array that contains the resource locations of XML configuration metadata. A plain or relative path (for example, context.xml) is 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 that represents a resource URL (i.e., a path prefixed with classpath:, file:, http:, etc.) is used as is.

@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:

If you omit both the locations and the value attributes from the @ContextConfiguration annotation, the TestContext framework tries 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". The following example shows how to do so:

To load an ApplicationContext for your tests by using Groovy scripts that use the Groovy Bean Definition DSL, you can 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.

The following example shows how to specify Groovy configuration files:

If you omit both the locations and value attributes from the @ContextConfiguration annotation, the TestContext framework tries 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 loads your application context from "classpath:com/example/MyTestContext.groovy". The following example shows how to use the default:

To load an ApplicationContext for your tests by using annotated classes (see Java-based container configuration), you can annotate your test class with @ContextConfiguration and configure the classes attribute with an array that contains references to annotated classes. The following example shows how to do so:

If you omit the classes attribute from the @ContextConfiguration annotation, the TestContext framework tries to detect the presence of default configuration classes. Specifically, AnnotationConfigContextLoader and AnnotationConfigWebContextLoader detect all static nested classes of the test class that meet the requirements for configuration class implementations, as specified in the @Configuration Javadoc. 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. In the following example, the OrderServiceTest class declares a static nested configuration class named Config that is automatically used to load the ApplicationContext for the test class:

It may sometimes be desirable to mix XML configuration files, Groovy scripts, and annotated classes (typically @Configuration classes) to configure an ApplicationContext 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 (such as Spring Boot) provide first-class support for loading an ApplicationContext from different types of resources simultaneously (for example, 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 for each test context. However, this does not mean that you cannot use both. One exception to the general rule is that the GenericGroovyXmlContextLoader and 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 through @ContextConfiguration, and, with the standard testing support in the TestContext framework, you have the following options.

If you want to use resource locations (for example, XML or Groovy) and @Configuration classes to configure your tests, you must pick one as the entry point, and that one must include or import the other. For example, in XML or Groovy scripts, you can include @Configuration classes by using component scanning or defining 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 define either a set of XML or Groovy resource locations or a set of @Configuration classes from which your production ApplicationContext is loaded, but you still have the freedom to include or import the other type of configuration.

To configure an ApplicationContext for your tests by 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 are then 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 (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. The following example shows how to use initializers:

You can also omit the declaration of XML configuration files, Groovy scripts, or annotated classes in @ContextConfiguration entirely and instead declare only ApplicationContextInitializer classes, which are then responsible for registering beans in the context — for example, by programmatically loading bean definitions from XML files or configuration classes. The following example shows how to do so:

@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 are 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 next example, which uses XML resource locations, the ApplicationContext for ExtendedTest is loaded from base-config.xml and extended-config.xml, in that order. Beans defined in extended-config.xml can, therefore, override (that is, replace) those defined in base-config.xml. The following example shows how one class can extend another and use both its own configuration file and the superclass’s configuration file:

Similarly, in the next example, which uses annotated classes, the ApplicationContext for ExtendedTest is loaded from the BaseConfig and ExtendedConfig classes, in that order. Beans defined in ExtendedConfig can, therefore, override (that is, replace) those defined in BaseConfig. The following example shows how one class can extend another and use both its own configuration class and the superclass’s configuration class:

In the next example, which uses context initializers, the ApplicationContext for ExtendedTest is initialized by using BaseInitializer and ExtendedInitializer. 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. The following example shows how one class can extend another and use both its own initializer and the superclass’s initializer:

Spring 3.1 introduced first-class support in the framework for the notion of environments and profiles (AKA “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.

Consider two examples with XML configuration and @Configuration classes:

When TransferServiceTest is run, its ApplicationContext is loaded from the app-config.xml configuration file in the root of the classpath. If you inspect app-config.xml, you can see 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, in the dev profile, and in 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 is created and populated with test data, and the accountRepository bean is wired with a reference to the development DataSource. That is 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 included only when no other profile is specifically activated. You can use this 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 with @Configuration classes instead of XML:

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

As with the XML-based configuration example, we still annotate TransferServiceTest with @ActiveProfiles("dev"), but this time we specify all four configuration classes by using 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 @ActiveProfiles annotation, you can declare @ActiveProfiles once on a base class, and subclasses 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:

@ActiveProfiles also supports an inheritProfiles attribute that can be used to disable the inheritance of active profiles, as the following example shows:

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

To resolve active bean definition profiles programmatically, you can implement a custom ActiveProfilesResolver and register it by using the resolver attribute of @ActiveProfiles. For further information, see the corresponding Javadoc. The following example demonstrates how to implement and register a custom OperatingSystemActiveProfilesResolver:

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

Spring 3.2 introduced support for loading a WebApplicationContext in integration tests. To instruct the TestContext framework to load a WebApplicationContext instead of a standard ApplicationContext, you can 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 is set to src/main/webapp. This is interpreted as a path relative to the root of your JVM (normally the path to your project). If you are familiar with the directory structure of a web application in a Maven project, you know that src/main/webapp is the default location for the root of your WAR. If you need to override this default, you can provide an alternate path to the @WebAppConfiguration annotation (for example, @WebAppConfiguration("src/test/webapp")). If you wish to reference a base resource path from the classpath instead of the file system, you can use Spring’s classpath: prefix.

Note that Spring’s testing support for WebApplicationContext implementations is on par with its support for standard ApplicationContext implementations. When testing with a WebApplicationContext, you are free to declare XML configuration files, Groovy scripts, or @Configuration classes by using @ContextConfiguration. You are also free to use any other test annotations, such as @ActiveProfiles, @TestExecutionListeners, @Sql, @Rollback, and others.

The remaining examples in this section show some of the various configuration options for loading a WebApplicationContext. The following example shows the TestContext framework’s support for convention over configuration:

If you annotate a test class with @WebAppConfiguration without specifying a resource base path, the resource path effectively defaults to file:src/main/webapp. Similarly, if you declare @ContextConfiguration without specifying resource locations, annotated classes, or context initializers, Spring tries to detect the presence of your configuration by using conventions (that is, WacTests-context.xml in the same package as the WacTests class or static nested @Configuration classes).

The following example shows 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.

The following example shows 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.

Once the TestContext framework loads an ApplicationContext (or WebApplicationContext) for a test, that context is 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 is used to load it. Consequently, the unique combination of configuration parameters is 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:

For example, if TestClassA specifies {"app-config.xml", "test-config.xml"} for the locations (or value) attribute of @ContextConfiguration, the TestContext framework loads the corresponding ApplicationContext and stores 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 is 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.

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. You can configure the maximum size from the command line or a build script by setting a JVM system property named spring.test.context.cache.maxSize. As an alternative, you can set the same property programmatically by using 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, you can set the log level for the org.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 Spring Testing Annotations). This instructs Spring to remove the context from the cache and rebuild the application context before running the next test. Note that support for the @DirtiesContext annotation is provided by the DirtiesContextBeforeModesTestExecutionListener and the DirtiesContextTestExecutionListener, which are enabled by default.

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 ApplicationContext instances. For example, if you are developing a Spring MVC web application, you typically have a root WebApplicationContext loaded by Spring’s ContextLoaderListener and a child WebApplicationContext loaded by 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, you can write integration tests that use context hierarchies by declaring context configuration with the @ContextHierarchy annotation, 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, you can also 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 (that is, 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 remaining JUnit 4-based examples in this section show common configuration scenarios for integration tests that require the use of context hierarchies.

Test-managed transactions are transactions that are managed declaratively by using the TransactionalTestExecutionListener or programmatically by using TestTransaction (described later). You should not confuse such transactions with Spring-managed transactions (those managed directly by Spring within the ApplicationContext loaded for tests) or application-managed transactions (those managed programmatically within application code that is invoked by tests). Spring-managed and application-managed transactions typically participate in test-managed transactions. However, you should use caution 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).

Annotating a test method with @Transactional causes the test to be run within a transaction that is, by default, automatically rolled back after completion of the test. If a test class is annotated with @Transactional, each test method within that class hierarchy runs within a transaction. Test methods that are not annotated with @Transactional (at the class or method level) are not run within a transaction. Furthermore, tests that are annotated with @Transactional but have the propagation type set to NOT_SUPPORTED are not 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 Transaction Rollback and Commit Behavior, there is no need to clean up the database after the createUser() method runs, since any changes made to the database are automatically rolled back by the TransactionalTestExecutionListener. See PetClinic Example for an additional example.

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.

Since Spring Framework 4.1, you can interact with test-managed transactions programmatically by using the static methods in TestTransaction. For example, you can use TestTransaction 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 (see the Javadoc for TestTransaction for further details):

Occasionally, you may 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 running your test or to verify expected transactional commit behavior after your test runs (if the test was configured to commit the transaction). TransactionalTestExecutionListener supports the @BeforeTransaction and @AfterTransaction annotations for exactly such scenarios. You can 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 runs at the appropriate time.

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

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

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

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 later. See the Javadoc for individual methods in ScriptUtils for further details.

ResourceDatabasePopulator provides an object-based API for programmatically populating, initializing, or cleaning up a database by 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 running the scripts. Each of the configuration options has a reasonable default value. See the Javadoc for details on default values. To run 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 executes the scripts against a DataSource:

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

In addition to the aforementioned mechanisms for running SQL scripts programmatically, you can declaratively configure SQL scripts in the Spring TestContext Framework. Specifically, you can declare the @Sql annotation on a test class or test method to configure the resource paths to SQL scripts that should be run against a given database 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.

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 want to use the Spring TestContext Framework with an alternative runner (such as JUnit 4’s Parameterized runner) or third-party runners (such as the MockitoJUnitRunner), you can, optionally, use Spring’s support for JUnit rules instead.

The following code listing shows the minimal requirements for configuring a test class to run with the custom Spring Runner:

In the preceding example, @TestExecutionListeners is configured with an empty list, to disable the default listeners, which otherwise would require an ApplicationContext to be configured through @ContextConfiguration.

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

SpringClassRule is a JUnit TestRule that supports class-level features of the Spring TestContext Framework, whereas SpringMethodRule is a JUnit MethodRule that 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 of being independent of any org.junit.runner.Runner implementation and can, therefore, be combined with existing alternative runners (such as JUnit 4’s Parameterized) or third-party runners (such as the MockitoJUnitRunner).

To support the full functionality of the TestContext framework, you must combine a SpringClassRule with a SpringMethodRule. The following example shows the proper way to declare these rules in an integration test:

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 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 you can use 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 you can use to run SQL statements to query the database. You can use such queries to confirm database state both before and after running 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 JDBC Testing Support, AbstractTransactionalJUnit4SpringContextTests also provides convenience methods that delegate to methods in JdbcTestUtils by using the aforementioned jdbcTemplate. Furthermore, AbstractTransactionalJUnit4SpringContextTests provides an executeSqlScript(..) method for running SQL scripts against the configured DataSource.

The Spring TestContext Framework offers full integration with the JUnit Jupiter testing framework, introduced in JUnit 5. By annotating test classes with @ExtendWith(SpringExtension.class), you can implement standard JUnit Jupiter-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.

Furthermore, thanks to the rich extension API in JUnit Jupiter, Spring can provide the following features above and beyond the feature set that Spring supports for JUnit 4 and TestNG:

The following code listing shows how to configure a test class to use the SpringExtension in conjunction with @ContextConfiguration:

Since you can also use annotations in JUnit 5 as meta-annotations, Spring can provide the @SpringJUnitConfig and @SpringJUnitWebConfig composed annotations to simplify the configuration of the test ApplicationContext and JUnit Jupiter.

The following example uses @SpringJUnitConfig to reduce the amount of configuration used in the previous example:

Similarly, the following example uses @SpringJUnitWebConfig to create a WebApplicationContext for use with JUnit Jupiter:

See the documentation for @SpringJUnitConfig and @SpringJUnitWebConfig in Spring JUnit Jupiter Testing Annotations for further details.

SpringExtension implements the ParameterResolver extension API from JUnit Jupiter, which lets Spring provide dependency injection for test constructors, test methods, and test lifecycle callback methods.

Specifically, SpringExtension can inject dependencies from the test’s ApplicationContext into test constructors and methods that are annotated with @BeforeAll, @AfterAll, @BeforeEach, @AfterEach, @Test, @RepeatedTest, @ParameterizedTest, and others.

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

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 you can use 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 you can use to execute SQL statements to query the database. You can use such queries to confirm database state both before and after running 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 JDBC Testing Support, AbstractTransactionalTestNGSpringContextTests also provides convenience methods that delegate to methods in JdbcTestUtils by using the aforementioned jdbcTemplate. Furthermore, AbstractTransactionalTestNGSpringContextTests provides an executeSqlScript(..) method for running SQL scripts against the configured DataSource.

The fluent API in the example from the preceding section requires a few static imports, such as MockMvcRequestBuilders.*, MockMvcResultMatchers.*, and MockMvcBuilders.*. An easy way to find these classes is to search for types that match MockMvc*. If you use Eclipse or the Eclipse-based Spring Tool Suite, be sure to add them as “favorite static members” in the Eclipse preferences under Java → Editor → Content Assist → Favorites. Doing so lets you use content assist after typing the first character of the static method name. Other IDEs (such as IntelliJ) may not require any additional configuration. Check the support for code completion on static members.

You have two main options for creating an instance of MockMvc. The first is to load Spring MVC configuration through the TestContext framework, which loads the Spring configuration and injects a WebApplicationContext into the test to use to build a MockMvc instance. The following example shows how to do so:

Your second option is to manually create a controller instance without loading Spring configuration. Instead, basic default configuration, roughly comparable to that of the MVC JavaConfig or the MVC namespace, is automatically created. You can customize it to a degree. The following example shows how to do so:

Which setup option should you use?

The webAppContextSetup loads your actual Spring MVC configuration, resulting in a more complete integration test. Since the TestContext framework caches the loaded Spring configuration, it helps keep tests running fast, even as you introduce more tests in your test suite. Furthermore, you can inject mock services into controllers through Spring configuration to remain focused on testing the web layer. The following example declares a mock service with Mockito:

You can then inject the mock service into the test to set up and verify your expectations, as the following example shows:

The standaloneSetup, on the other hand, is a little closer to a unit test. It tests one controller at a time. You can manually inject the controller with mock dependencies, and it does not involve loading Spring configuration. Such tests are more focused on style and make it easier to see which controller is being tested, whether any specific Spring MVC configuration is required to work, and so on. The standaloneSetup is also a very convenient way to write ad-hoc tests to verify specific behavior or to debug an issue.

As with most “integration versus unit testing” debates, there is no right or wrong answer. However, using the standaloneSetup does imply the need for additional webAppContextSetup tests in order to verify your Spring MVC configuration. Alternatively, you can write all your tests with webAppContextSetup, in order to always test against your actual Spring MVC configuration.

No matter which MockMvc builder you use, all MockMvcBuilder implementations provide some common and very useful features. For example, you can declare an Accept header for all requests and expect a status of 200 as well as a Content-Type header in all responses, as follows:

In addition, third-party frameworks (and applications) can pre-package setup instructions, such as those in a MockMvcConfigurer. The Spring Framework has one such built-in implementation that helps to save and re-use the HTTP session across requests. You can use it as follows:

See the Javadoc for ConfigurableMockMvcBuilder for a list of all MockMvc builder features or use the IDE to explore the available options.

You can perform requests that use any HTTP method, as the following example shows:

You can also perform file upload requests that internally use MockMultipartHttpServletRequest so that there is no actual parsing of a multipart request. Rather, you have to set it up to be similar to the following example:

You can specify query parameters in URI template style, as the following example shows:

You can also add Servlet request parameters that represent either query or form parameters, as the following example shows:

If application code relies on Servlet request parameters and does not check the query string explicitly (as is most often the case), it does not matter which option you use. Keep in mind, however, that query parameters provided with the URI template are decoded while request parameters provided through the param(…​) method are expected to already be decoded.

In most cases, it is preferable to leave the context path and the Servlet path out of the request URI. If you must test with the full request URI, be sure to set the contextPath and servletPath accordingly so that request mappings work, as the following example shows:

In the preceding example, it would be cumbersome to set the contextPath and servletPath with every performed request. Instead, you can set up default request properties, as the following example shows:

The preceding properties affect every request performed through the MockMvc instance. If the same property is also specified on a given request, it overrides the default value. That is why the HTTP method and URI in the default request do not matter, since they must be specified on every request.

You can define expectations by appending one or more .andExpect(..) calls after performing a request, as the following example shows:

MockMvcResultMatchers.* provides a number of expectations, some of which are further nested with more detailed expectations.

Expectations fall in two general categories. The first category of assertions verifies properties of the response (for example, the response status, headers, and content). These are the most important results to assert.

The second category of assertions goes beyond the response. These assertions let you inspect Spring MVC specific aspects, such as which controller method processed the request, whether an exception was raised and handled, what the content of the model is, what view was selected, what flash attributes were added, and so on. They also let you inspect Servlet specific aspects, such as request and session attributes.

The following test asserts that binding or validation failed:

Many times, when writing tests, it is useful to dump the results of the performed request. You can do so as follows, where print() is a static import from MockMvcResultHandlers:

As long as request processing does not cause an unhandled exception, the print() method prints all the available result data to System.out. Spring Framework 4.2 introduced a log() method and two additional variants of the print() method, one that accepts an OutputStream and one that accepts a Writer. For example, invoking print(System.err) prints the result data to System.err, while invoking print(myWriter) prints the result data to a custom writer. If you want to have the result data logged instead of printed, you can invoke the log() method, which logs the result data as a single DEBUG message under the org.springframework.test.web.servlet.result logging category.

In some cases, you may want to get direct access to the result and verify something that cannot be verified otherwise. This can be achieved by appending .andReturn() after all other expectations, as the following example shows:

If all tests repeat the same expectations, you can set up common expectations once when building the MockMvc instance, as the following example shows:

Note that common expectations are always applied and cannot be overridden without creating a separate MockMvc instance.

When a JSON response content contains hypermedia links created with Spring HATEOAS, you can verify the resulting links by using JsonPath expressions, as the following example shows:

When XML response content contains hypermedia links created with Spring HATEOAS, you can verify the resulting links by using XPath expressions:

When setting up a MockMvc instance, you can register one or more Servlet Filter instances, as the following example shows:

Registered filters are invoked through the MockFilterChain from spring-test, and the last filter delegates to the DispatcherServlet.

As mentioned earlier Spring MVC Test is built on the Servlet API mock objects from the spring-test module and does not use a running Servlet container. Therefore, there are some important differences compared to full end-to-end integration tests with an actual client and server running.

The easiest way to think about this is by starting with a blank MockHttpServletRequest. Whatever you add to it is what the request becomes. Things that may catch you by surprise are that there is no context path by default; no jsessionid cookie; no forwarding, error, or async dispatches; and, therefore, no actual JSP rendering. Instead, “forwarded” and “redirected” URLs are saved in the MockHttpServletResponse and can be asserted with expectations.

This means that, if you use JSPs, you can verify the JSP page to which the request was forwarded, but no HTML is rendered. In other words, the JSP is not invoked. Note, however, that all other rendering technologies that do not rely on forwarding, such as Thymeleaf and Freemarker, render HTML to the response body as expected. The same is true for rendering JSON, XML, and other formats through @ResponseBody methods.

Alternatively, you may consider the full end-to-end integration testing support from Spring Boot with @WebIntegrationTest. See the Spring Boot Reference Guide.

There are pros and cons for each approach. The options provided in Spring MVC Test are different stops on the scale from classic unit testing to full integration testing. To be certain, none of the options in Spring MVC Test fall under the category of classic unit testing, but they are a little closer to it. For example, you can isolate the web layer by injecting mocked services into controllers, in which case you are testing the web layer only through the DispatcherServlet but with actual Spring configuration, as you might test the data access layer in isolation from the layers above it. Also, you can use the stand-alone setup, focusing on one controller at a time and manually providing the configuration required to make it work.

Another important distinction when using Spring MVC Test is that, conceptually, such tests are the server-side, so you can check what handler was used, if an exception was handled with a HandlerExceptionResolver, what the content of the model is, what binding errors there were, and other details. That means that it is easier to write expectations, since the server is not a black box, as it is when testing it through an actual HTTP client. This is generally an advantage of classic unit testing: It is easier to write, reason about, and debug but does not replace the need for full integration tests. At the same time, it is important not to lose sight of the fact that the response is the most important thing to check. In short, there is room here for multiple styles and strategies of testing even within the same project.

The framework’s own tests include many sample tests intended to show how to use Spring MVC Test. You can browse these examples for further ideas. Also, the spring-mvc-showcase project has full test coverage based on Spring MVC Test.

The most obvious question that comes to mind is “Why do I need this?” The answer is best found by exploring a very basic sample application. Assume you have a Spring MVC web application that supports CRUD operations on a Message object. The application also supports paging through all messages. How would you go about testing it?

With Spring MVC Test, we can easily test if we are able to create a Message, as follows:

What if we want to test the form view that lets us create the message? For example, assume our form looks like the following snippet:

How do we ensure that our form produce the correct request to create a new message? A naive attempt might resemble the following:

This test has some obvious drawbacks. If we update our controller to use the parameter message instead of text, our form test continues to pass, even though the HTML form is out of synch with the controller. To resolve this we can combine our two tests, as follows:

This would reduce the risk of our test incorrectly passing, but there are still some problems:

The overall problem is that testing a web page does not involve a single interaction. Instead, it is a combination of how the user interacts with a web page and how that web page interacts with other resources. For example, the result of a form view is used as the input to a user for creating a message. In addition, our form view can potentially use additional resources that impact the behavior of the page, such as JavaScript validation.

This section describes how to integrate MockMvc and HtmlUnit. Use this option if you want to use the raw HtmlUnit libraries.

In the previous sections, we have seen how to use MockMvc in conjunction with the raw HtmlUnit APIs. In this section, we use additional abstractions within the Selenium WebDriver to make things even easier.