test_which.py 文件源码

def test_which_follows_symlink(self):
        " which() follows symlinks and returns its path. "
        fname = 'original'
        symname = 'extra-crispy'
        bin_dir = tempfile.mkdtemp()
        bin_path = os.path.join(bin_dir, fname)
        sym_path = os.path.join(bin_dir, symname)
        save_path = os.environ['PATH']
        try:
            # setup
            os.environ['PATH'] = bin_dir
            with open(bin_path, 'w') as fp:
                pass
            os.chmod(bin_path, 0o400)
            os.symlink(bin_path, sym_path)

            # should not be found because symlink points to non-executable
            assert pexpect.which(symname) is None

            # but now it should -- because it is executable
            os.chmod(bin_path, 0o700)
            assert pexpect.which(symname) == sym_path

        finally:
            # restore,
            os.environ['PATH'] = save_path

            # destroy scratch files, symlinks, and folders,
            if os.path.exists(sym_path):
                os.unlink(sym_path)
            if os.path.exists(bin_path):
                os.unlink(bin_path)
            if os.path.exists(bin_dir):
                os.rmdir(bin_dir)