Mixing Assert and Act in AAA unit testing syntax

Question

Is it OK to mix Assert and Act steps? Is AAA more of a guideline than a rule? Or am I missing something?

Here is my test:

[TestMethod]
public void CancelButtonSelected_DontCancelTwiceThenCancel_DialogCloses()
{
    // Arrange
    IAddAddressForm form = Substitute.For<IAddAddressForm>();
    // Indicate that when Show CancelMessage is called it 
    //  should return cancel twice (saying we want to cancel the cancel)
    //  then it should return ok
    form.ShowCancelMessage().Returns(DialogResult.Cancel, 
         DialogResult.Cancel, DialogResult.OK);

    AddAddressController controller = new AddAddressController(form);
    AddressItem item = TestHelper.CreateAddressBob();

    // Act
    EnterAddressInfo(form, controller, item);
    controller.CancelButtonSelected();
    Assert.IsTrue(form.DialogResult == DialogResult.None);

    controller.CancelButtonSelected();
    Assert.IsTrue(form.DialogResult == DialogResult.None);

    controller.CancelButtonSelected();

    // Assert
    Assert.IsTrue(form.DialogResult == DialogResult.Cancel);
}

So I call a method 3 times. After each call, I want to make sure that we did not really cancel the dialog. Then on the third call, the dialog should be canceled.

Is this "legal" use of AAA syntax/styling?

Answer 1

AAA is a guideline to make your unit tests more readable. In the example you provided I would argue you have not achieved that goal.

I think the following tests make the scenario you are testing more readable.

[TestMethod]
public void CancelButtonSelected_ShouldSetDialogResultToNone_WhenFirstCancelButtonIsSelected()
{
    // Arrange
    IAddAddressForm form = ArrangeFormForCancelButtonSelectedTests();
    AddAddressController controller = ArrangeControllerForCancelButtonSelectedTests();

    // Act
    controller.CancelButtonSelected();

    // Assert
    Assert.IsTrue(form.DialogResult == DialogResult.None);
}

[TestMethod]
public void CancelButtonSelected_ShouldSetDialogResultToNone_WhenSecondCancelButtonIsSelected()
{
    // Arrange
    IAddAddressForm form = ArrangeFormForCancelButtonSelectedTests();
    AddAddressController controller = ArrangeControllerForCancelButtonSelectedTests();

    // Act
    controller.CancelButtonSelected();
    controller.CancelButtonSelected();

    // Assert
    Assert.IsTrue(form.DialogResult == DialogResult.None);

}

[TestMethod]
public void CancelButtonSelected_ShouldSetDialogResultToCancel_WhenThirdCancelButtonIsSelected()
{
    // Arrange
    IAddAddressForm form = ArrangeFormForCancelButtonSelectedTests();
    AddAddressController controller = ArrangeControllerForCancelButtonSelectedTests();

    // Act
    controller.CancelButtonSelected();
    controller.CancelButtonSelected();
    controller.CancelButtonSelected();

    // Assert
    Assert.IsTrue(form.DialogResult == DialogResult.Cancel);
}