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A Very Simple Framework

Метки: python

As mentioned, a primary goal of this code is to make the writing of unit testing code very simple, even simpler than with JUnit. As further needs are discovered during the use of this system, then that functionality can be added, but to start with the framework will just provide a way to easily create and run tests, and report failure if something breaks (success will produce no results other than normal output that may occur during the running of the test). My intended use of this framework is in makefiles, and make aborts if there is a non- zero return value from the execution of a command. The build process will consist of compilation of the programs and execution of unit tests, and if make gets all the way through successfully then the system will be validated, otherwise it will abort at the place of failure. The error messages will report the test that failed but not much else, so that you can provide whatever granularity that you need by writing as many tests as you want, each one covering as much or as little as you find necessary.

In some sense, this framework provides an alternative place for all those “print” statements I’ve written and later erased over the years.

To create a set of tests, you start by making a static inner class inside the class you wish to test (your test code may also test other classes; it’s up to you). This test code is distinguished by inheriting from UnitTest:

# UnitTesting/UnitTest.py
# The basic unit testing class

class UnitTest:
    testID = ""
    errors = []
    # Override cleanup() if test object creation allocates non-memory
    # resources that must be cleaned up:
    def cleanup(self): pass
    # Verify a condition is true:
    def affirm(condition):
        if(!condition)
            UnitTest.errors.append("failed: " + UnitTest.testID)

The only testing method [[ So far ]] is affirm( ) [2], which is protected so that it can be used from the inheriting class. All this method does is verify that something is true. If not, it adds an error to the list, reporting that the current test (established by the static testID, which is set by the test-running program that you shall see shortly) has failed. Although this is not a lot of information-you might also wish to have the line number, which could be extracted from an exception-it may be enough for most situations.

Unlike JUnit (which uses setUp( ) and tearDown( ) methods), test objects will be built using ordinary Python construction. You define the test objects by creating them as ordinary class members of the test class, and a new test class object will be created for each test method (thus preventing any problems that might occur from side effects between tests). Occasionally, the creation of a test object will allocate non-memory resources, in which case you must override cleanup( ) to release those resources.