Python: Essential Reference

11. Testing, Debugging, Profiling, and Tuning

Unlike programs in languages such as C or Java, Python programs are not processed by a compiler that produces an executable program. In those languages, the compiler is the first line of defense against programming errors—catching mistakes such as calling functions with the wrong number of arguments or assigning improper values to variables (that is, type checking). In Python, however, these kinds of checks do not occur until a program runs. Because of this, you will never really know if your program is correct until you run and test it. Not only that, unless you are able to run your program in a way that executes every possible branch of its internal control-flow, there is always some chance of ...