Enable mock to verify that an activity should not be called (#428)

Added to the MockCallWrapper a way to specify that we expect Zero calls to the activity.

internal/internal_workflow_testsuite_test.go

@@ -91,6 +91,18 @@ func (s *WorkflowTestSuiteUnitTest) Test_ActivityMockFunction() {
 	env.AssertExpectations(s.T())
 }
 
+func (s *WorkflowTestSuiteUnitTest) Test_ActivityMockFunctionZero() {
+	env := s.NewTestWorkflowEnvironment()
+	env.OnActivity(testActivityHello, mock.Anything, "world").Never()
+	env.RegisterWorkflow(testWorkflowHello)
+	env.ExecuteWorkflow(testWorkflowHello)
+
+	s.True(env.IsWorkflowCompleted())
+	s.NotNil(env.GetWorkflowError())
+	s.Contains(env.GetWorkflowError().Error(), "unexpected call: testActivityHello(string,string)")
+	env.AssertExpectations(s.T())
+}
+
 func (s *WorkflowTestSuiteUnitTest) Test_ActivityByNameMockFunction() {
 	mockActivity := func(ctx context.Context, msg string) (string, error) {
 		return "mock_" + msg, nil

internal/workflow_testsuite.go

@@ -449,6 +449,13 @@ func (c *MockCallWrapper) Times(i int) *MockCallWrapper {
 	return c
 }
 
+// Never indicates that the mock should not be called.
+func (c *MockCallWrapper) Never() *MockCallWrapper {
+	c.call.Maybe()
+	c.call.Panic(fmt.Sprintf("unexpected call: %s(%s)", c.call.Method, c.call.Arguments.String()))
+	return c
+}
+
 // Run sets a handler to be called before returning. It can be used when mocking a method such as unmarshalers that
 // takes a pointer to a struct and sets properties in such struct.
 func (c *MockCallWrapper) Run(fn func(args mock.Arguments)) *MockCallWrapper {