Cpp Unit Once And Only Once Hack

I've created a Python hack so I don't have to create/change my CppUnit test names in three places. The script reads a .cpp file ( eg tests.cpp ), finds the names of all your tests, and writes the appropriate declarations to the corresponding .h file.

Note that this is a personal hack, released here in case it's useful to anyone, and comes with no guarantees, assurances, or claims to being good code : ) This might also duplicate known techniques, be an inferior solution, be brittle code, etc, etc.

However, I have found it extremely useful, and thus I share it here.

Usage:

Save the script: paste this Python source code into a text editor and save in the dir with your tests
Remove spaces: Delete the first 2 spaces from each line
Change the filenames ( tests.cpp and tests.h ) to match your test file names
- ( Note that only one .cpp and one .h file are supported for now )
Insert markers into your header file, to denote the blocks that will be autogenerated
- ( eg '// BEGIN_GENERATED_BLOCK_TEST_MACROS //' and '// END_GENERATED_BLOCK_TEST_MACROS //' )
- ( For full example, see sample .h file at CppUnitOnceAndOnlyOnceHackExampleHeaderFile )
Run it: You can run it from the command line, but much cooler to make it part of your build process:
- In Visual Studio, add a "Pre Build" event that is simply "python cppUnitHack.py"
- In unixland, do something with your makefiles, I guess : )
Celebrate: You should now be able to write and change test names once and only once!

Note that the script expects spaces for your ( C++ ) source code indentation; if you use tabs this script may need modification.

Feel free to refactor this source code, or tell me why it sucks, or whatever you like : )

--HarlanWood

Python script follows:


        import os, re


        # change these to the name your test files

        testSourceFileName = 'tests.cpp'

        testHeaderFileName = 'tests.h'


        # gather test declarations from the source file:


        testSourceFile = file( testSourceFileName, 'r')

        source = testSourceFile.read()

        testSourceFile.close()


        # note that we ignore tests whose names are line-commented out with '//' 

        # but would still include multi-line commented out tests, if the comment began on an earlier line

        # so use line-comments '//' if you want to comment out tests 

        testNames = re.findall( r'\ns*void Tests::(test\w+)\(\)', source )


        testMacros         = [ ( '  CPPUNIT_TEST( %s );' % testName ) for testName in testNames ]

        memberDeclarations = [ ( '  void %s();' % testName ) for testName in testNames ]


        # read header file, delete old version:


        testHeaderFile = file( testHeaderFileName, 'r')

        header = testHeaderFile.read()

        testHeaderFile.close()

        os.remove( testHeaderFileName )


        # substitute in the test names:


        cre = re.compile( '( *// BEGIN_GENERATED_BLOCK_TEST_MACROS //)' +                     

        '(.*?)' +                     

        '( *// END_GENERATED_BLOCK_TEST_MACROS //)', 

        re.DOTALL )


        header = cre.sub( r'\1\n\n' + '\n'.join( testMacros ) + r'\n\n\3', header )


        cre = re.compile( '( *// BEGIN_GENERATED_BLOCK_MEMBER_DECLARATIONS //)' +                     

        '(.*?)' +                     

        '( *// END_GENERATED_BLOCK_MEMBER_DECLARATIONS //)', 

        re.DOTALL )


        header = cre.sub( r'\1\n\n' + '\n'.join( memberDeclarations ) + r'\n\n\3', header )


        # finally, create a 'new' header file with the generated contents:


        testHeaderFile = file( testHeaderFileName, 'w')

        testHeaderFile.write( header )

        testHeaderFile.close()