Question

How can I write unit test to the following code:

public Image Get(BrowserName browser)
{
    // if no screenshot mode specified it means that regular screenshot needed
    return this.Get(browser, ScreenshotMode.Regular);
}

public Image Get(BrowserName browser, ScreenshotMode mode) {            
    // some code omitted here
}

Answer 1

That’s typically done with a partial mock, and they can be a little yucky.

First, the method you are mocking must be virtual. Otherwise Rhino Mocks can’t intercept the method. So let’s change your code to this:

public Image Get(BrowserName browser)
{
    // if no screenshot mode specified it means that regular screenshot needed
    return this.Get(browser, ScreenshotMode.Regular);
}

public virtual Image Get(BrowserName browser, ScreenshotMode mode) {            
    // some code omitted here
}

Note that the second method is virtual now. We can then setup our partial mock like so:

//Arrange
var yourClass = MockRepository.GeneratePartialMock<YourClass>();
var bn = new BrowserName();
yourClass.Expect(m => m.Get(bn, ScreenshotMode.Regular));

//Act
yourClass.Get(bn);

//Assert
yourClass.VerifyAllExpectations();

That’s with the AAA Rhino Mocks syntax. If you prefer to use record / playback, you can use that too.

---

So that’s how you would do it. A possibly better solution is if ScreenshotMode is an enum and you have C# 4 at your disposal, just make it an optional parameter:

public Image Get(BrowserName browser, ScreenshotMode mode = ScreenshotMode.Regular)
{
    //Omitted code.
}

Now you don’t have two methods, so there is no need to test that one calls another.