import org.scalatest.mockito.MockitoSugar

// First, create the mock object
val mockCollaborator = mock[Collaborator]

// Create the class under test and pass the mock to it
classUnderTest = new ClassUnderTest
classUnderTest.addListener(mock)

// Use the class under test
classUnderTest.addDocument("Document", new Array[Byte](0))
classUnderTest.addDocument("Document", new Array[Byte](0))

// Then verify the class under test used the mock object as expected
verify(mockCollaborator).documentAdded("Document")
verify(mockCollaborator, times(2)).documentChanged("Document")