ScalaMock | Native Scala mocking framework | Functional Programming library

you should use AsyncMockFactory with an appropriate test suite and Futures as described in the docs at https://scalamock.org/user-guide/integration/

Assuming that you are using JaCoCo with cobertura coverage you need to declare the dependencies and the plugin to run the command mvn cobertura:cobertura.

So this is still not ideal, but using "expects.onCall" I can get the output I want

You don't have the right dependency:

According to your build.gradle you didn't add scala-reflect dependency

https://mvnrepository.com/artifact/org.scala-lang/scala-reflect/2.13.3

scala-library is not enough if you want to use Scala reflection.

Try to add scala-reflect

I think it is due to mismatch between Scala version with which the code is compiled and Scala version of the runtime.

Spark 2.4.2 was prebuilt using Scala 2.12 but Scala 2.4.5 is prebuilt with Scala 2.11 as mentioned at - https://spark.apache.org/downloads.html.

This issue should go away if you use spark libraries compiled in 2.11

If you are sure data field will not be used in the test you could trick the compiler with null.asInstanceOf[A]

GeneratorDrivenPropertyChecks seems to have been removed in ScalaTest 3.1.0

We made it private so that it would not hold up the 3.1.0 release any longer. I wanted to investigate a better way to integrate shrinking, as has been done by tools such as Hedgehog. The 3.2.0 release we wanted to be exactly the same as 3.1.0 except for modularization. After that we plan to complete and release ScalaTest's Generator. Meanwhile we figured everyone would continue to use ScalaCheckDrivenPropertyChecks and Gen, which is available here:

https://github.com/scalatest/scalatestplus-scalacheck

Instead try using ScalaCheckDrivenPropertyChecks like so

This: