Test::Unit Wins in an Upset

Over the last couple of days I decided to write a small program without the benefit of Ruby's Test::Unit module. Why? Well, it's only been in the last year and a half or so that I've been rigorously testing code with frameworks like JUnit and Test::Unit, and I wanted reassure myself that I'm really better off now.

The thing is, even if you haven't created test cases, you still have to test your code. So my coding in the last two days has gone like this:

Make a change
Run the whole program (It worked, yea!)
Run it again with different input (Failed. Boo.)
Interpret the stack trace
Correct the error
Run the whole program again (It worked, yea!)
Run it again with different input (This time it worked, yea!)
Run it again with still another input (Oh, shit.)
Interpret the stack trace
Correct the error
Repeat over and over with every change and every kind of input

By the end of the project I was running the program seven times, to test seven different inputs, each time I made a change. Instead, I should have just run a unit test that tests only the module that was changed.

The time to run the whole program takes a few seconds longer than running a test case of a module. The time to run it seven times to test different inputs takes much longer than running a test suite. The time to type in the different inputs for each run of the program is far more than the time it would take to create the test cases. All these seconds really add up over several hours of coding.

Bottom line: I'm more convinced than ever that by taking the time to create good test cases I'm saving tons of time over the life of a project. Suite!