Mock Argument mismatch is hidden by Exceptions

  def "NPE"() {
    given:
    List<String> list = Mock()

    when:
    def len = list.get(1).length()

    then:
    len == 5
    1 * list.get(0) >> "hello"
  }

Fails with java.lang.NullPointerException: Cannot invoke method length() on null object. We loose any information, that this was caused by a wrong argument to the mock.

If there are Unmatched invocations, then they should be reported as well.

Too few invocations for:

1 * list.get(0) >> "hello"   (0 invocations)

Unmatched invocations (ordered by similarity):

1 * list.get(1)
One or more arguments(s) didn't match:
0: argument == expected
   |        |  |
   1        |  0
            false