def debug_script(src, pm=False, globs=None):

    "Debug a test script.  `src` is the script, as a string."

    import pdb

    # Note that tempfile.NameTemporaryFile() cannot be used.  As the

    # docs say, a file so created cannot be opened by name a second time

    # on modern Windows boxes, and execfile() needs to open it.

    srcfilename = tempfile.mktemp(".py", "doctestdebug")

    f = open(srcfilename, 'w')

    f.write(src)

    f.close()

    try:

        if globs:

            globs = globs.copy()

        else:

            globs = {}

        if pm:

            try:

                execfile(srcfilename, globs, globs)

            except:

                print sys.exc_info()[1]

                pdb.post_mortem(sys.exc_info()[2])

        else:

            # Note that %r is vital here.  '%s' instead can, e.g., cause

            # backslashes to get treated as metacharacters on Windows.

            pdb.run("execfile(%r)" % srcfilename, globs, globs)

    finally:

        os.remove(srcfilename)