Ahead of Time Support for Tests

This chapter covers Spring’s Ahead of Time (AOT) support for integration tests using the Spring TestContext Framework.

The testing support extends Spring’s core AOT support with the following features.

Build-time detection of all integration tests in the current project that use the TestContext framework to load an ApplicationContext.
- Provides explicit support for test classes based on JUnit Jupiter and JUnit 4 as well as implicit support for TestNG and other testing frameworks that use Spring’s core testing annotations — as long as the tests are run using a JUnit Platform TestEngine that is registered for the current project.
Build-time AOT processing: each unique test ApplicationContext in the current project will be refreshed for AOT processing.
Runtime AOT support: when executing in AOT runtime mode, a Spring integration test will use an AOT-optimized ApplicationContext that participates transparently with the context cache.

The @ContextHierarchy annotation is currently not supported in AOT mode.

To provide test-specific runtime hints for use within a GraalVM native image, you have the following options.

Implement a custom TestRuntimeHintsRegistrar and register it globally via META-INF/spring/aot.factories.
Implement a custom RuntimeHintsRegistrar and register it globally via META-INF/spring/aot.factories or locally on a test class via @ImportRuntimeHints.
Annotate a test class with @Reflective or @RegisterReflectionForBinding.
See Runtime Hints for details on Spring’s core runtime hints and annotation support.

The TestRuntimeHintsRegistrar API serves as a companion to the core RuntimeHintsRegistrar API. If you need to register global hints for testing support that are not specific to particular test classes, favor implementing RuntimeHintsRegistrar over the test-specific API.

If you implement a custom ContextLoader, it must implement AotContextLoader in order to provide AOT build-time processing and AOT runtime execution support. Note, however, that all context loader implementations provided by the Spring Framework and Spring Boot already implement AotContextLoader.

If you implement a custom TestExecutionListener, it must implement AotTestExecutionListener in order to participate in AOT processing. See the SqlScriptsTestExecutionListener in the spring-test module for an example.