Mockito + kotlin Object + BitRise = fail

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.