In one of my recent PRs, there was this small change, apart ~1000 other lines of code:

object MockData {
  ...
  val NOW = mock<Now> {
      on { ms } doReturn msTIMEOUT
      on { s } doReturn secTIMEOUT.toLong()
      on { date } doReturn Date(msTIMEOUT)
  }
  ...
}

It gave me lots of such errors on BitRise, though locally everything worked perfectly:

...
com.mycompany.packagename.ClassName100Test > Test case 100 FAILED
java.lang.NoClassDefFoundError at com.mycompany.packagename.ClassName100Test.kt:57

com.mycompany.packagename.ClassName101Test > Test case 101 FAILED
org.mockito.exceptions.misusing.UnfinishedStubbingException at ClassName101Test.kt:35

com.mycompany.packagename.ClassName102Test > Test case 102 FAILED
java.lang.NoClassDefFoundError at ClassName102Test.kt:43

com.mycompany.packagename.ClassName103Test > Test case 103 FAILED
java.lang.NoClassDefFoundError at ClassName103Test.kt:47

com.mycompany.packagename.ClassName104Test > Test case 104 FAILED
java.lang.NoClassDefFoundError at ClassName104Test.java:-2

com.mycompany.packagename.ClassName105Test > Test case 105 FAILED
java.lang.NoClassDefFoundError at ClassName105Test.java:-2

com.mycompany.packagename.ClassName106Test > Test case 106 FAILED
java.lang.NoClassDefFoundError at ClassName106Test.java:-2

com.mycompany.packagename.ClassName107Test > Test case 107 FAILED
java.lang.NoClassDefFoundError at ClassName107Test.java:-2
...

I can’t make any other conclusion but: avoid using Mockito mocking inside of Kotlin Objects.

Yes, it’s. If you’re researching about how to use native debugger with Android studio there’re no so many decisions of your problem. You shouldn’t use native libraries. Just integrate your C++ sources into main project – so debugger would work.

I’ve created bug-report so, I hope, Google will close it. But there’s still no any info.