Unit testing in Java vs. Smalltalk
When you write unit tests, the minimal requirement before being able to try them out is that they compile. In Smalltalk, this means things like syntactic well-formedness, and perhaps the presence of global variables (i.e. classes) that you reference in the test method body.
It’s very quick and comfortable in Smalltalk to develop supported by unit testing: to write tests you know will fail, and refine away the failures until your test suite passes.
In Java, it’s much less comfortable, because besides the basic requirement of syntactic well-formedness, all the methods, classes, interfaces, and packages that your code relies on, directly or indirectly, must be present in the system before you can even try a run of the test suite! This makes for a less incremental style of development.
It would be very interesting to see a unit-testing framework for Java that simply treated a non-compiling test as a normal test failure, rather than a complete show-stopper, and which let you continue with the other tests in the suite. At the end of a run, it would include the non-compiling tests in the final reports just the same way as any other unexpectedly-failing test is reported.
4 comments February 22nd, 2008 tonyg