Fix a bug in the CRE SDK standard test verifying calls are async, it allowed the first request to respond before the second was made (#1554)

* Fix a bug in the CRE SDK standard test verifying calls are async, it allowed the first request to respond before the second was made

* Add comment

Author: nolag

pkg/workflows/wasm/host/standard_test.go

@@ -73,6 +73,9 @@ func TestStandardErrors(t *testing.T) {
 }
 
 func TestStandardCapabilityCallsAreAsync(t *testing.T) {
+	// This test expects basic action's PerformAction to be called twice asynchronously and the results concatenated.
+	// To ensure the calls are actually async, the mock will block the first call until the second call is made.
+	// The first call sets InputThing to true, the second to false.
 	t.Parallel()
 	mockExecutionHelper := NewMockExecutionHelper(t)
 	mockExecutionHelper.EXPECT().GetWorkflowExecutionID().Return("id")
@@ -98,12 +101,10 @@ func TestStandardCapabilityCallsAreAsync(t *testing.T) {
 		require.NoError(t, err)
 
 		// Don't return until the second call has been executed
-		defer func() {
-			if !input.InputThing {
-				mt.Lock()
-			}
-			defer mt.Unlock()
-		}()
+		if input.InputThing {
+			mt.Lock()
+		}
+		defer mt.Unlock()
 		return &sdk.CapabilityResponse{
 			Response: &sdk.CapabilityResponse_Payload{Payload: payload},
 		}, nil