Don't add MockitoExtension during migration when unsafe (#875)

[timtebeek]

• Fixes MockitoExtension gets added even when not necessary #875

Problem

AddMockitoExtensionIfAnnotationsUsed (run as part of Mockito1to3Migration) added @ExtendWith(MockitoExtension.class) to any test using @Mock/@Spy/@Captor/@InjectMocks, even when Mockito support was already provided another way. This was at best redundant and at worst broke the test lifecycle — e.g. when SpringExtension is present (it already initializes @Mock fields), when a parent class/interface/meta-annotation provides the extension, or when MockitoAnnotations.openMocks(this) is used explicitly.

Changes

Removed from the migration (do no harm)

• AddMockitoExtensionIfAnnotationsUsed and its companion AddMockitoJupiterDependency are no longer applied as part of Mockito1to3Migration. They are kept as commented-out entries with an explanatory comment so the intent is captured and they aren't re-added without first teaching the recipes about these cases.

Hardened the standalone recipe (AddMockitoExtensionIfAnnotationsUsed)

• Skips when any @ExtendWith/@RunWith is already present (covers SpringExtension).
• Skips non-concrete classes (interfaces, enums, annotations, abstract bases).
• Only annotates classes that themselves declare a Mockito annotation.

Preserved the PowerMock migration path

• PowerMockRunnerDelegateToRunWith now replaces @RunWith(PowerMockRunner.class) with @RunWith(MockitoJUnitRunner.class) when the class uses Mockito annotations (instead of relying on the now-removed generic auto-add), and still removes it entirely otherwise.

Tests

• Added cases for the hardened recipe (SpringExtension present, abstract class, interface + helper without mocks).
• Added standalone AddMockitoJupiterDependencyTest to keep that recipe covered.
• Updated migration/integration tests to the new, correct behavior (explicit initMocks is now preserved/migrated to openMocks + AutoCloseable instead of being replaced by the extension).

Notes / not covered

The hardened recipe still does not detect the inheritance, meta-annotation (e.g. @MockitoSettings), or explicit-initMocks cases — these now only matter to someone invoking the standalone recipe directly, since it no longer runs in the migration.

Full test suite passes locally.

[DidierLoiseau]

I think you’ll still need to add the extension when migrating from JMockit to Mockito, otherwise the migration won’t work.

(I’m not familiar with that migration though)

[timtebeek]

Good catch — you're right for one of the two JMockit styles. I dug into it:

• The JMockitToMockito migration already carries the extension over for the annotation-based style via ChangeType: @ExtendWith(JMockitExtension.class) → @ExtendWith(MockitoExtension.class) and @RunWith(JMockit.class) → @RunWith(MockitoJUnitRunner.class). Almost all of the JMockit tests use this style, and they keep working.
• The gap is the javaagent style — @Mocked with no @ExtendWith/@RunWith (which is exactly this test). There's no extension to convert, so the migrated @Mock fields would never be initialized.

I've pushed a fix: re-added the (now hardened) AddMockitoExtensionIfAnnotationsUsed scoped to JMockitToMockito only, plus a version-correct mockito-junit-jupiter:5.x dependency. Because the hardened recipe bails when any @ExtendWith/@RunWith is already present, the annotation-based tests (which already have MockitoExtension after ChangeType) are left untouched, while the agent-based case now gets the extension. Restored this test's expected output accordingly.