Faking a private function in a button click code

Hi Mike,

I'd recommend you to use the actual class instead of using the accessor wrapper.

In the test you can instantiate the LoginWindow class as the class under test. The act statement sould change into:

Isolate.Invoke.Method(target, "btnOk_Click", sender, e);

In general, Isolator provides a lot of the functionality that the accessors provide through Isolate.NonPublic APIs and through ObjectState.

Please let us know if it works.

Regards,
Elisha,
Typemock Support

Hi Elisha,

if I try this test code now:

            // Arrange
            LoginWindow fake = Isolate.Fake.Instance<LoginWindow>();
            Isolate.NonPublic.WhenCalled(fake, "checkPassword").WillReturn(false);
            Isolate.Swap.NextInstance<LoginWindow>().With(fake);

            // Arrange
            LoginWindow target = new LoginWindow();
            object sender = new object();
            RoutedEventArgs e = new RoutedEventArgs();

            Isolate.Fake.StaticMethods<System>(Members.ReturnRecursiveFakes);
                        
            // Act
            Isolate.Invoke.Method(target, "btnOk_Click", sender, e);
            
            // Assert
            Isolate.Verify.WasCalledWithAnyArguments(
                () => System.Windows.MessageBox.Show(
                    string.Empty,
                    string.Empty,
                    MessageBoxButton.OK,
                    MessageBoxImage.Stop)
                    );

... the assert (Isolate.Verify) throws a not called exception.

If point the cursor between the braces:

RoutedEventArgs e = new RoutedEventArgs();

your "helper" appears with "Fake RoutedEvent Alt+7". If I press Alt+7 the text "fakeRoutedEvent" will be inserted. Now the helper says "Set Object Behavior Alt+7". If I press Alt+7 again, Visual Studio (2010) crashes every time ... :cry:

What can I do? How should I instance sender and e?

Ciao,
Mike

Hi Mike,

I've edited the test a little. The test will check that if checkPassword() returns false the message box is shown:

LoginWindow target = new LoginWindow();
Isolate.NonPublic.WhenCalled(target, "checkPassword").WillReturn(false);
Isolate.Fake.StaticMethods<MessageBox>(Members.ReturnRecursiveFakes);

object sender = new object();
RoutedEventArgs e = Isolate.Fake.Instance<RoutedEventArgs>();
Isolate.Invoke.Method(target, "btnOk_Click", sender, e);
            
Isolate.Verify.WasCalledWithAnyArguments(
    () => System.Windows.MessageBox.Show(
        string.Empty,
        string.Empty,
        System.Windows.MessageBoxButton.OK,
        System.Windows.MessageBoxImage.Stop));

As can be seen in the test, the RoutedEventArgs can be created as a fake instance without accessing it's constructor directly.

Please let me know if it helps.

Regards,
Elisha,
Typemock Support

Hi Elisha,

that works! Now, my two tests look like:

        public void btnOk_ClickTest_passwordOk()
        {
            // Arrange
            LoginWindow target = new LoginWindow();

            Isolate.NonPublic.WhenCalled(target, "checkPassword").WillReturn(true);
            Isolate.WhenCalled(() => {target.DialogResult = true;}).IgnoreCall();

            object sender = new object();
            RoutedEventArgs e = Isolate.Fake.Instance<RoutedEventArgs>();
                        
            // Act
            Isolate.Invoke.Method(target, "btnOk_Click", sender, e);
            
            // Assert
            Isolate.Verify.WasCalledWithArguments(
                () => { target.DialogResult = true; }).Matching(args => (bool)args[0] == true);
        }

(Is the assert OK? It works, but writing "target.DialogResult = true;" and checking for true feels a little bit strange ... :wink: )

        public void btnOk_ClickTest_passwordFailed()
        {
            // Arrange
            LoginWindow target = new LoginWindow();
            Isolate.NonPublic.WhenCalled(target, "checkPassword").WillReturn(false);
            Isolate.Fake.StaticMethods<System>(Members.ReturnRecursiveFakes);

            object sender = new object();
            RoutedEventArgs e = Isolate.Fake.Instance<RoutedEventArgs>();

            // Act
            Isolate.Invoke.Method(target, "btnOk_Click", sender, e);

            // Assert
            Isolate.Verify.WasCalledWithAnyArguments(
                () => System.Windows.MessageBox.Show(
                    string.Empty,
                    string.Empty,
                    MessageBoxButton.OK,
                    MessageBoxImage.Stop)
                    );
        }

Now "my colleague" changes the production code into ...

            if (isValid)
            {
                MessageBox.Show("Bingo");
                this.DialogResult = true;
            }

... and I want to make shure that the test fails now. I want to make shure, that any message window will fail. I can add something like that:

            Isolate.Verify.WasNotCalled(
                () => System.Windows.MessageBox.Show(
                    string.Empty)
                    );

But if my colleague adds a caption, the verify will not work. So, I don't know how many parameters the Messagebox.Show will have. How can I make shure, that I catch all of them?

Thanks,

Mike

Mike,

First, regarding the assert - I would use another API:

Isolate.Verify.WasCalledWithExactArguments(() => { target.DialogResult = true; });

This would verify the arguments against what you passed in, meaning checks true was set.

Regarding the second question, this is a good point - I will add a feature suggestion to provide an option that the WasCalledWithAny API will not be overload specific. To make the test more robust you can use the non public API that's string based but does not rely on arguments:

Isolate.Verify.NonPublic.WasCalled(typeof(MessageBox), "Show");

Hope this helps.
Doron
Typemock Support