Module org.junit.jupiter.api
Package org.junit.jupiter.api.io

Annotation Interface TempDir

@Target({ANNOTATION_TYPE,FIELD,PARAMETER}) @Retention(RUNTIME) @Documented @API(status=STABLE, since="5.10") public @interface TempDir
@TempDir can be used to annotate a field in a test class or a parameter in a test class constructor, lifecycle method, or test method of type Path or File that should be resolved into a temporary directory.

Creation

The temporary directory is only created if a field in a test class or a parameter in a test class constructor, lifecycle method, or test method is annotated with @TempDir. An ExtensionConfigurationException or a ParameterResolutionException will be thrown in one of the following cases:

  • If the field type or parameter type is neither Path nor File.
  • If a field is declared as final.
  • If the temporary directory cannot be created.
  • If the field type or parameter type is File and a custom factory is used, which creates a temporary directory that does not belong to the default file system.

Scope

By default, a separate temporary directory is created for every declaration of the @TempDir annotation. For better isolation when using @TestInstance(Lifecycle.PER_METHOD) semantics, you can annotate an instance field or a parameter in the test class constructor with @TempDir so that each test method uses a separate temporary directory. Alternatively, if you want to share a temporary directory across all tests in a test class, you should declare the annotation on a static field or on a parameter of a @BeforeAll method.

Old behavior

You can revert to the old behavior of using a single temporary directory by setting the "junit.jupiter.tempdir.scope" configuration parameter to per_context. In that case, the scope of the temporary directory depends on where the first @TempDir annotation is encountered when executing a test class. The temporary directory will be shared by all tests in a class when the annotation is present on a static field or on a parameter of a @BeforeAll method. Otherwise — for example, when @TempDir is only used on instance fields or on parameters in test, @BeforeEach, or @AfterEach methods — each test will use its own temporary directory.

Clean Up

By default, when the end of the scope of a temporary directory is reached, — when the test method or class has finished execution — JUnit will attempt to clean up the temporary directory by recursively deleting all files and directories in the temporary directory and, finally, the temporary directory itself. Symbolic and other types of links, such as junctions on Windows, are not followed. A warning is logged when deleting a link that targets a location outside the temporary directory. In case deletion of a file or directory fails, an IOException will be thrown that will cause the test or test class to fail.

The cleanup() attribute allows you to configure the CleanupMode. If the cleanup mode is set to NEVER, the temporary directory will not be cleaned up after the test completes. If the cleanup mode is set to ON_SUCCESS, the temporary directory will only be cleaned up if the test completes successfully. By default, the ALWAYS clean up mode will be used, but this can be configured globally by setting the "junit.jupiter.tempdir.cleanup.mode.default" configuration parameter.

Since:
5.4

  • Field Details

    • DEFAULT_FACTORY_PROPERTY_NAME

      @API(status=MAINTAINED, since="5.13.3") static final String DEFAULT_FACTORY_PROPERTY_NAME
      Property name used to set the default temporary directory factory class name: "junit.jupiter.tempdir.factory.default"

      Supported Values

      Supported values include fully qualified class names for types that implement TempDirFactory.

      If not specified, the default is TempDirFactory.Standard.

      Since:
      5.10
      See Also:

    • SCOPE_PROPERTY_NAME

      @Deprecated @API(status=DEPRECATED, since="5.9") static final String SCOPE_PROPERTY_NAME
      Deprecated.
      Property name used to set the scope of temporary directories created via the @TempDir annotation: "junit.jupiter.tempdir.scope"

      Supported Values

      • per_context: creates a single temporary directory for the entire test class or method, depending on where @TempDir is first declared
      • per_declaration: creates separate temporary directories for each declaration site of the @TempDir annotation

      If not specified, the default is per_declaration.

      Since:
      5.8
      See Also:

    • DEFAULT_CLEANUP_MODE_PROPERTY_NAME

      @API(status=MAINTAINED, since="5.13.3") static final String DEFAULT_CLEANUP_MODE_PROPERTY_NAME
      The name of the configuration parameter that is used to configure the default CleanupMode.

      If this configuration parameter is not set, CleanupMode.ALWAYS will be used as the default.

      Since:
      5.9
      See Also:

  • Element Details