Exploration Through Example

Example-driven development, Agile testing, context-driven testing, Agile programming, Ruby, and other things of interest to Brian Marick

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Wed, 26 Feb 2003

More on command lines and tests

A faithful correspondent notes that my entry on command lines as refactored tests is incoherent. Let me explain the structure of the app.

It's named Timeclock. It's a client-server app. There are two user interfaces, the GUI and the command line. Command line commands are just Ruby functions, and the command line is normally used through the Ruby interpreter.

Now let's add the tests to the picture:

The top set tests the command line. Among other things, they check that return values and exceptions from the Session are turned into pleasing messages to the user. The bottom set are direct tests of the Session: they create Session objects, call methods on them, and check the results.

To make the Session tests shorter and clearer, there should be (and are) test utility methods:

However, my observation was that a goodly chunk of the test utility methods would look a lot like the command line commands. The command line commands can already be used in unit tests (namely their own), so why not use them as utility routines when testing the Session? That means that the command line tests can be used to both test the command line and the underlying Session methods. Doing so appeals to my desire to eliminate duplicate code.

## Posted at 09:34 in category /testing [permalink] [top]