Mock Config Extension

MockConfigExtension is JUnit Jupier extension that handles mocking of the Config class. It replaces the MockConfigRule that was used for previous JUnit versions.

Creating the extension

Like with any extension, the only thing you need to do in order to incorporate it in your test class is to add an @ExtendWith annotation.

public class MyTest {
    // Code ...

Basic mocking

For the basic usecase, where all the tests in the class use the same mocked configuration, just create a method with the signature public static Stream<MockConfigDescriptor<?>> mockConfiguration(). E.g.:

public static Stream<MockConfigDescriptor<?>> mockConfiguration() {
    return Stream.of(
        // "general" version
        MockConfigDescriptor.of(ConfigValues.UserSessionTimeOutInterval, 30),

        // Specific 4.2 config value
        MockConfigDescriptor.of(ConfigValues.PassDiscardSupported, Version.v4_2, true)

Mocking different config values per test

Sometimes, different methods will need different config values. This can be achieved by creating different methods (with a similar signature) to supply the mocked config values, and annotating the test with the @MockedConfig annotation to specify that it should use the aforementioned method. E.g.:

public static Stream<MockConfigDescriptor<?>> mockSpecialConfiguration() {
    return Stream.of(MockConfigDescriptor.of(ConfigValues.UserSessionTimeOutInterval, 60));

public void specialTest() {
    // Code