Testing

The org.springframework.mock.env package contains mock implementations of the Environment and PropertySource abstractions (see Bean Definition Profiles and PropertySource Abstraction). MockEnvironment and MockPropertySource are useful for developing out-of-container tests for code that depends on environment-specific properties.

The org.springframework.mock.jndi package contains a partial implementation of the JNDI SPI, which you can use to set up a simple JNDI environment for test suites or stand-alone applications. If, for example, JDBC DataSource instances get bound to the same JNDI names in test code as they do in a Jakarta EE container, you can reuse both application code and configuration in testing scenarios without modification.

The org.springframework.mock.web package contains a comprehensive set of Servlet API mock objects that are useful for testing web contexts, controllers, and filters. These mock objects are targeted at usage with Spring’s Web MVC framework and are generally more convenient to use than dynamic mock objects (such as EasyMock) or alternative Servlet API mock objects (such as MockObjects).

The Spring MVC Test framework builds on the mock Servlet API objects to provide an integration testing framework for Spring MVC. See MockMvc.

The org.springframework.mock.http.server.reactive package contains mock implementations of ServerHttpRequest and ServerHttpResponse for use in WebFlux applications. The org.springframework.mock.web.server package contains a mock ServerWebExchange that depends on those mock request and response objects.

Both MockServerHttpRequest and MockServerHttpResponse extend from the same abstract base classes as server-specific implementations and share behavior with them. For example, a mock request is immutable once created, but you can use the mutate() method from ServerHttpRequest to create a modified instance.

In order for the mock response to properly implement the write contract and return a write completion handle (that is, Mono<Void>), it by default uses a Flux with cache().then(), which buffers the data and makes it available for assertions in tests. Applications can set a custom write function (for example, to test an infinite stream).

The WebTestClient builds on the mock request and response to provide support for testing WebFlux applications without an HTTP server. The client can also be used for end-to-end tests with a running server.

The org.springframework.test.util package contains several general purpose utilities for use in unit and integration testing.

AopTestUtils is a collection of AOP-related utility methods. You can use these methods to obtain a reference to the underlying target object hidden behind one or more Spring proxies. For example, if you have configured a bean as a dynamic mock by using a library such as EasyMock or Mockito, and the mock is wrapped in a Spring proxy, you may need direct access to the underlying mock to configure expectations on it and perform verifications. For Spring’s core AOP utilities, see AopUtils and AopProxyUtils.

ReflectionTestUtils is a collection of reflection-based utility methods. You can use these methods in testing scenarios where you need to change the value of a constant, set a non-public field, invoke a non-public setter method, or invoke a non-public configuration or lifecycle callback method when testing application code for use cases such as the following:

TestSocketUtils is a simple utility for finding available TCP ports on localhost for use in integration testing scenarios.

The org.springframework.test.web package contains ModelAndViewAssert, which you can use in combination with JUnit, TestNG, or any other testing framework for unit tests that deal with Spring MVC ModelAndView objects.

The Spring TestContext Framework provides consistent loading of Spring ApplicationContext instances and WebApplicationContext instances as well as caching of those contexts. Support for the caching of loaded contexts is important, because startup time can become an issue — not because of the overhead of Spring itself, but because the objects instantiated by the Spring container take time to instantiate. For example, a project with 50 to 100 Hibernate mapping files might take 10 to 20 seconds to load the mapping files, and incurring that cost before running every test in every test fixture leads to slower overall test runs that reduce developer productivity.

Test classes typically declare either an array of resource locations for XML or Groovy configuration metadata — often in the classpath — or an array of component classes that is used to configure the application. These locations or classes are the same as or similar to those specified in web.xml or other configuration files for production deployments.

By default, once loaded, the configured ApplicationContext is reused for each test. Thus, the setup cost is incurred only once per test suite, and subsequent test execution is much faster. In this context, the term “test suite” means all tests run in the same JVM — for example, all tests run from an Ant, Maven, or Gradle build for a given project or module. 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) the TestContext framework can be configured to reload the configuration and rebuild the application context before executing the next test.

See Context Management and Context Caching with the TestContext framework.

When the TestContext framework loads your application context, it can optionally configure instances of your test classes by using Dependency Injection. This provides a convenient mechanism for setting up test fixtures by using preconfigured beans from your application context. A strong benefit here is that you can reuse application contexts across various testing scenarios (for example, for configuring Spring-managed object graphs, transactional proxies, DataSource instances, and others), thus avoiding the need to duplicate complex test fixture setup for individual test cases.

As an example, consider a scenario where we have a class (HibernateTitleRepository) that implements data access logic for a Title domain entity. We want to write integration tests that test the following areas:

See dependency injection of test fixtures with the TestContext framework.

One common issue in tests that access a real database is their effect on the state of the persistence store. Even when you use a development database, changes to the state may affect future tests. Also, many operations — such as inserting or modifying persistent data — cannot be performed (or verified) outside of a transaction.

The TestContext framework addresses this issue. By default, the framework creates and rolls back a transaction for each test. You can write code that can assume the existence of a transaction. If you call transactionally proxied objects in your tests, they behave correctly, according to their configured transactional semantics. In addition, if a test method deletes the contents of selected tables while running within the transaction managed for the test, the transaction rolls back by default, and the database returns to its state prior to execution of the test. Transactional support is provided to a test by using a PlatformTransactionManager bean defined in the test’s application context.

If you want a transaction to commit (unusual, but occasionally useful when you want a particular test to populate or modify the database), you can tell the TestContext framework to cause the transaction to commit instead of roll back by using the @Commit annotation.

See transaction management with the TestContext framework.

The Spring TestContext Framework provides several abstract support classes that simplify the writing of integration tests. These base test classes provide well-defined hooks into the testing framework as well as convenient instance variables and methods, which let you access:

In addition, you may want to create your own custom, application-wide superclass with instance variables and methods specific to your project.

See support classes for the TestContext framework.

TestContext encapsulates the context in which a test is run (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 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 component classes, active bean definition profiles, test property sources, context hierarchies, and WebApplicationContext support.

SmartContextLoader is an extension of the ContextLoader interface that supersedes the original minimal ContextLoader SPI. Specifically, a SmartContextLoader can choose to process resource locations, component 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 TestExecutionListener implementations explicitly for a test class, its subclasses, and its nested classes by using the @TestExecutionListeners annotation. See annotation support and the javadoc for @TestExecutionListeners for details and examples.

Registering 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 an entire test suite. 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 Boot and 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:

By default, if a test execution event listener throws an exception while consuming an event, that exception will propagate to the underlying testing framework in use (such as JUnit or TestNG). For example, if the consumption of a BeforeTestMethodEvent results in an exception, the corresponding test method will fail as a result of the exception. In contrast, if an asynchronous test execution event listener throws an exception, the exception will not propagate to the underlying testing framework. For further details on asynchronous exception handling, consult the class-level javadoc for @EventListener.

If you want a particular test execution event listener to process events asynchronously, you can use Spring’s regular @Async support. For further details, consult the class-level javadoc for @EventListener.

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 component 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 component 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 component 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 component 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 component 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 component classes as well as the context initializers declared by any superclasses. Specifically, the resource locations or component 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, component classes, or context initializers.

If the inheritLocations or inheritInitializers attribute in @ContextConfiguration is set to false, the resource locations or component 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 component 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:

The Spring Framework has first-class support 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:

The Spring Framework has first-class support for the notion of an environment with a hierarchy of property sources, and 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.

As of Spring Framework 5.2.5, the TestContext framework provides support for dynamic properties via the @DynamicPropertySource annotation. This annotation can be used in integration tests that need to add properties with dynamic values to the set of PropertySources in the Environment for the ApplicationContext loaded for the integration test.

In contrast to the @TestPropertySource annotation that is applied at the class level, @DynamicPropertySource must be applied to a static method that accepts a single DynamicPropertyRegistry argument which is used to add name-value pairs to the Environment. Values are dynamic and provided via a Supplier which is only invoked when the property is resolved. Typically, method references are used to supply values, as can be seen in the following example which uses the Testcontainers project to manage a Redis container outside of the Spring ApplicationContext. The IP address and port of the managed Redis container are made available to components within the test’s ApplicationContext via the redis.host and redis.port properties. These properties can be accessed via Spring’s Environment abstraction or injected directly into Spring-managed components – for example, via @Value("${redis.host}") and @Value("${redis.port}"), respectively.

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, component 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.

To provide comprehensive web testing support, the TestContext framework has a ServletTestExecutionListener that is enabled by default. When testing against a WebApplicationContext, this TestExecutionListener sets up default thread-local state by using Spring Web’s RequestContextHolder before each test method and creates a MockHttpServletRequest, a MockHttpServletResponse, and a ServletWebRequest based on the base resource path configured with @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 shows which mocks can be autowired into your test instance. Note that the WebApplicationContext and MockServletContext are both cached across the test suite, whereas the other mocks are managed per test method by the ServletTestExecutionListener.

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.

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 via the SpringProperties mechanism.

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 run, 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 that requires the same application context. 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.

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 component 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 Jupiter based examples in this section show common configuration scenarios for integration tests that require the use of context hierarchies.

Single test class with context hierarchy

Class hierarchy with implicit parent context

Class hierarchy with merged context hierarchy configuration

Class hierarchy with overridden context hierarchy configuration

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. Note that @Transactional is not supported on test lifecycle methods — for example, methods annotated with JUnit Jupiter’s @BeforeAll, @BeforeEach, etc. Furthermore, tests that are annotated with @Transactional but have the propagation attribute set to NOT_SUPPORTED or NEVER 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.

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.

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 run 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 Jupiter 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:

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 run, 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 run the populator against a java.sql.Connection or the execute(DataSource) method to run 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 run 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 individual SQL statements or the resource paths to SQL scripts that should be run against a given database before or after an integration test method. 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 provides 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 provides 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.

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 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, 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.

This setup allows you to test specific controller(s) via mock request and response objects, without a running server.

For WebFlux applications, use the following which loads infrastructure equivalent to the WebFlux Java config, registers the given controller(s), and creates a WebHandler chain to handle requests:

For Spring MVC, use the following which delegates to the StandaloneMockMvcBuilder to load infrastructure equivalent to the WebMvc Java config, registers the given controller(s), and creates an instance of MockMvc to handle requests:

This setup allows you to load Spring configuration with Spring MVC or Spring WebFlux infrastructure and controller declarations and use it to handle requests via mock request and response objects, without a running server.

For WebFlux, use the following where the Spring ApplicationContext is passed to WebHttpHandlerBuilder to create the WebHandler chain to handle requests:

For Spring MVC, use the following where the Spring ApplicationContext is passed to MockMvcBuilders.webAppContextSetup to create a MockMvc instance to handle requests:

This setup allows you to test functional endpoints via mock request and response objects, without a running server.

For WebFlux, use the following which delegates to RouterFunctions.toWebHandler to create a server setup to handle requests:

For Spring MVC there are currently no options to test WebMvc functional endpoints.

This setup connects to a running server to perform full, end-to-end HTTP tests:

In addition to the server setup options described earlier, you can also configure client options, including base URL, default headers, client filters, and others. These options are readily available following bindToServer(). For all other configuration options, you need to use configureClient() to transition from server to client configuration, as follows:

If the response is not expected to have content, you can assert that as follows:

If you want to ignore the response content, the following releases the content without any assertions:

You can use expectBody() without a target type to perform assertions on the raw content rather than through higher level Object(s).

To verify the full JSON content with JSONAssert:

To verify JSON content with JSONPath:

To test potentially infinite streams such as "text/event-stream" or "application/x-ndjson", start by verifying the response status and headers, and then obtain a FluxExchangeResult:

Now you’re ready to consume the response stream with StepVerifier from reactor-test:

WebTestClient is an HTTP client and as such it can only verify what is in the client response including status, headers, and body.

When testing a Spring MVC application with a MockMvc server setup, you have the extra choice to perform further assertions on the server response. To do that start by obtaining an ExchangeResult after asserting the body:

Then switch to MockMvc server response assertions:

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.

In the previous section, we saw how to use MockMvc with WebDriver. In this section, we use Geb to make our tests even Groovy-er.

The following annotations are supported with standard semantics for all configurations of the Spring TestContext Framework. Note that these annotations are not specific to tests and can be used anywhere in the Spring Framework.

The Spring Framework provides the following set of Spring-specific annotations that you can use in your unit and integration tests in conjunction with the TestContext framework. See the corresponding javadoc for further information, including default attribute values, attribute aliases, and other details.

Spring’s testing annotations include the following:

The following annotations are supported only when used in conjunction with the SpringRunner, Spring’s JUnit 4 rules, or Spring’s JUnit 4 support classes: