def test_one_merged_branch(self):
        """
        If a branch has been merged, it's safe to delete it.
        """
        self.command('git checkout -b branch1')

        self.make_commit()

        self.command('git checkout master')

        self.command('git merge branch1')

        self.assertEqual(['branch1'], self.merged_refs())

        If a branch has been merged, it's safe to delete it.
        
src/gitsweep/tests/test_inspector.py