Testing a Conditional Statement

Question

I want to test a method with no return, which only runs code if a passed in bool is set to true.

I'd like to test that when the bool is false, no code is called. I expect, this is maybe a case of refactoring to make my code more testable.

Code speaks a thousand words, so here's my method (constructor and dependencies left out for brevity):

...

public void Handle(Notification notification)
{
    if (notification.IsRestarting)
    {
        var installedVersion = _versionService.GetValue("Version");

        var packageVersion = "1.0.0";

        if (installedVersion.IsNullOrWhiteSpace())
        {
            _service.Initialise();
        }
    
        _versionService.SetValue("Version", packageVersion);
    }
}

...

I'm using Moq for mocking.

The _versionService actually sets the value in a SQL database table. This is a third-party service, though it is mockable.

So, if isRestarting is false, the method should do nothing. How do I test this, or make my code more testable?

Answer 1

You can check that your services were never called. Assuming that _versionService is a Mock<ISomeVersionService>. Some rough code -

[Test]
public void MyTest()
{
    //call the method
    Handle(new Notification { IsRestarting = false });

    //verify nothing happened
    _versionService.Verify(x => x.GetValue(It.IsAny<string>(), Times.Never))

    //handle _service similarly
}