Is it expected that new `androidInstrumentedTest` sourceSet doesn't inherit dependencies from `andro...

# multiplatform

[Big Chungus]

Is it expected that new androidInstrumentedTest sourceSet doesn't inherit dependencies from androidUnitTest nor sources from commonTest?

[Jeff Lockhart]

A change in the new source set layout is that androidInstrumentedTest no longer inherits from commonTest.

I'm not sure about the dependency sharing. Did that used to be the case in the old source set layout?

[Sebastian Sellmair [JB]]

Yes! InstrumentedTests need to dependOn commonTest explicitly if want that behavior!

[Sebastian Sellmair [JB]]

The new default will be, that only unitTest source sets will dependOn commonTest

[Jeff Lockhart]

In my case, I need androidInstrumentedTest to inherit from commonTest, but not androidUnitTest, as the common tests require running on a device for the Android platform. So I still employ this workaround to sever the dependency for androidUnitTest.

[Sebastian Sellmair [JB]]

Please do not remove a dependsOn edge by casting something to mutableSet. This is entirely unexpected and can lead to many issues in tooling.

[Jeff Lockhart]

Is there some other way to accomplish removing this androidUnitTest dependency on commonTest? I haven't run into any issues with this workaround. Without it, the tests attempt to run as Android unit tests and fail.

[Sebastian Sellmair [JB]]

No, dependOn edges cannot be removed. The fact that you do not experience any issues is quite surprising, but can change with any kotlin release. In your case I would not use commonTest, but create a custom shared test source set.

I am also open for discussing the default dependsOn edge from Android unit tests to commonTest.

[Jeff Lockhart]

I think it would certainly make sense to allow control over which of the two Android test types were the desired edge for common tests. Maybe a gradle property option to choose between the two.

Generally a test suite can either be compatible with running on pure JVM or mocked by Robolectric (androidUnitTest) or has Android-specific dependencies that require androidInstrumentedTest. In my case, it's the latter. The majority of code is shared between the JVM and Android source sets, but the underlying Android library requires a valid Android Context and loads a native JNI library which only works on a physical Android device.

I think it's good that androidInstrumentedTest no longer depends on commonTest by default, as it's unlikely someone would want both androidUnitTest and androidInstrumentedTest to depend on commonTest. But it should be equally possible to choose androidInstrumentedTest as the edge that does depend on commonTest and not androidUnitTest.

Will it be possible to configure the source set dependency graph this way with the new source set DSL in 1.8.20?

[Jeff Lockhart]

@Sebastian Sellmair [JB] FYI, turns out this hack to remove androidUnitTest as a commonTest edge no longer works as of Kotlin 1.8. It worked up to 1.7.21. I'm looking forward to a solution for how to properly remove the edge or switch it to use androidInstrumentedTest. Please let me know if I can assist in any way.

[Sebastian Sellmair [JB]]

This is not surprising to me, as I mentioned: This set was used to incrementally update data in the KGP.
So, indeed you could help, but its okay if the time investment is too hight:
This could a a contribution from your side in 1.9.
If you’re interested, please send me a written proposal of the desired behaviour changes.
If the proposal gets accepted by me and my @stanislav.erokhin, then I can help you with the contribution. The code is OK to get into.

[Jeff Lockhart]

Ok, I'd be happy to write up a formal proposal. I'm assuming we'd want a solution for both the current preset API and the new source set DSL API. Where can I see the latest documentation for the DSL API so I can become more familiar with it?

Right now I'm thinking along the lines of something like this for the existing API:

kotlin {
    android {
        commonTestEdge = INSTRUMENTED // UNIT, INSTRUMENTED, or BOTH (default UNIT)
    }
}

// or

kotlin {
    android(commonTestEdge = INSTRUMENTED)
}

This would allow the user to configure either of the Android test edges to depend on common, or both, as it seems there are some users that use the commonTest source set for common test fixtures, but not necessarily tests that cannot run as either unit or instrumented.

This API change should not affect existing code, which would continue with the default behavior of BOTH pre-1.8 and UNIT post-1.8.

[Jeff Lockhart]

Based on this, the new DSL might similarly include the argument:

targetHierarchy.default {
    common {
        withAndroid(commonTestEdge = INSTRUMENTED)
    }
}

[Alex Vanyo]

Does that mean that you could define separate jvmUnitTest and jvmInstrumentedTest instead of jvmTest (if you wanted to)?

[Sebastian Sellmair [JB]]

Sorry this was not clear enough, but this is only about android. But yes you could do something like what you described already in 1.8.20

[Jeff Lockhart]

I tested this with 1.9.0-Beta-47 and it works great! No more build errors from androidUnitTest being connected to commonTest.

targetHierarchy.android {
    instrumentedTest.sourceSetTree.set(SourceSetTree.test)
    unitTest.sourceSetTree.set(SourceSetTree.unitTest)
}