MockitoExtension cannot be used with JUnit 5 in OSGi integration tests

[wborn]

The Mockito junit-jupiter JAR is missing OSGi bundle manifest entries so it cannot be used in OSGi integration tests.

We run some OSGi integration tests (using bnd) that have @Mocks so it would be easier if these mocks can be initialized by annotating classes with @MockitoExtension instead of using MockitoAnnotations.openMocks(this), see for example this FirmwareUpdateServiceTest.

What may complicate adding the manifest entries is that MockitoExtension is importing internal classes which aren't exported by the mockito-core bundle. What may help is to make junit-jupiter a bundle fragment with mockito-core as host.

[kriegfrj]

Fragments can be a bit of a pain.

@rotty3000 could offer some advice here - he did the OSGi metadata port for the JUnit 5 project itself. They had a similar problem, in that some of the bundles relied on internal packages of other bundles. I think that they ended up exporting the "internal" packages, but flagged them with an attribute to mark them as "internal use only".

[timothyjward]

I would also like to see a solution to this issue. Making the mockito-junit-jupiter jar into a fragment which exports the MockitoExtension package and attaches to mockito-core does sound like a good plan.

[rotty3000]

I've got a set of changes that makes mockito-junit-jupiter work in OSGi using the same strategy that junit5 used to identify "friend" packages that are exported but not intended for public use outside of mockito.

@raphw do you think your team would be interested?

[raphw]

Looks good to me, I had a look at the build and I know too little about OSGi to understand the effect the API guardian dependencies have but since the classes only carry annotations and the dependency is not required, I do not see any chance of a regression.

@TimvdLippe - could you have a second look, you know the build better then me. To me it looks like a good merge.

[rotty3000]

For your edification:
a) apiguardian does not bring with it any runtime dependencies (confirmed by the OSGi metadata)
b) the interaction between API guardian and bnd is explained here
c) the build adds a verifyOSGi gradle task glued onto check to make sure that future changes do not break the relationship required between mockito-core and mockito-junit-jupiter such that they continue working together in OSGi

[wborn]

Today I tried a recent version of Mockito 5 with OSGi but it doesn't work anymore, see also #2708. 😞
Perhaps some of the commenters here can help with fixing it?

[TimvdLippe]

@wborn Unfortunately I don't have a lot of experience with OSGi, but would be happy to review a PR that fixes it (with an included regression test). Apologies for the breakage!

[raphw]

I think there needs to be some form of import of the boot loader package that we add. Not sure if such an import is considered in OSGi, but I'd need a reproduction to look into it.