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Configuration Configuration with Context Customizers
A ContextCustomizer
is responsible for customizing the supplied
ConfigurableApplicationContext
after bean definitions have been loaded into the context
but before the context has been refreshed.
A ContextCustomizerFactory
is responsible for creating a ContextCustomizer
, based on
some custom logic which determines if the ContextCustomizer
is necessary for a given
test class — for example, based on the presence of a certain annotation. Factories are
invoked after ContextLoaders
have processed context configuration attributes for a test
class but before the MergedContextConfiguration
is created.
For example, Spring Framework provides the following ContextCustomizerFactory
implementation which is registered by default:
MockServerContainerContextCustomizerFactory
-
Creates a
MockServerContainerContextCustomizer
if WebSocket support is present in the classpath and the test class or one of its enclosing classes is annotated or meta-annotated with@WebAppConfiguration
.MockServerContainerContextCustomizer
instantiates a newMockServerContainer
and stores it in theServletContext
under the attribute namedjakarta.websocket.server.ServerContainer
.
Registering ContextCustomizerFactory
Implementations
You can register ContextCustomizerFactory
implementations explicitly for a test class, its
subclasses, and its nested classes by using the @ContextCustomizerFactories
annotation. See
annotation support
and the javadoc for
@ContextCustomizerFactories
for details and examples.
Automatic Discovery of Default ContextCustomizerFactory
Implementations
Registering ContextCustomizerFactory
implementations by using @ContextCustomizerFactories
is
suitable for custom factories that are used in limited testing scenarios. However, it can
become cumbersome if a custom factory needs to be used across an entire test suite. This
issue is addressed through support for automatic discovery of default
ContextCustomizerFactory
implementations through the SpringFactoriesLoader
mechanism.
For example, the modules that make up the testing support in Spring Framework and Spring
Boot declare all core default ContextCustomizerFactory
implementations under the
org.springframework.test.context.ContextCustomizerFactory
key in their
META-INF/spring.factories
properties files. The spring.factories
file for the
spring-test
module can be viewed
here.
Third-party frameworks and developers can contribute their own ContextCustomizerFactory
implementations to the list of default factories in the same manner through their own
spring.factories
files.
Merging ContextCustomizerFactory
Implementations
If a custom ContextCustomizerFactory
is registered via @ContextCustomizerFactories
, it
will be merged with the default factories that have been registered using the aforementioned
automatic discovery mechanism.
The merging algorithm ensures that duplicates are removed from the list and that locally declared factories are appended to the list of default factories when merged.
To replace the default factories for a test class, its subclasses, and its nested
classes, you can set the |