TrafficControl: The First Unit Tests - tcStation

The first unit tests for TrafficControl address one single station object. This will be a brain-storming session, where I add a lot of test cases without implementing them. In those cases, I have commented out the test cases that are yet to be implemented.

The commented test cases are not implemented yet. I also add a short description of the test cases.

When creating one station object, the default values must be verified:

• Is the station empty initially, both with regard to the number of trains and passengers?
• What happens if invalid coordinates are sent to the constructor of station? If the coordinates are float values, but too big (-100.0, 199)?
• What happens if the station name is already taken?

When creating test cases, I sometimes realise that I need to extend the existing target code to be more testable and observable. That's the very purpose of verification: identifying ways to improve the code.

The test case "station_noCoordinatesAtCreation()" reveals that it useful to add a boolean "hasCoordinates" and a method "tcStation::hasCoordinates();".

The next blog post will introduce Test-Driven Development and show an example of using that methodology.