def METHOD_NAME(self):
    """Test to add a new key"""
    o = ScmOverride({ 'set' : { 'commit' : '1234' } })
    match, scm = o.mangle(self.scm, Env())
    self.assertEqual(scm, {
        'scm' : "git",
        'url' : "git@git.com:foo/bar.git",
        'branch' : "develop",
        'commit' : "1234"
    }
    )
    o = ScmOverride({ 'set' : { 'commit' : "${COMMIT}" } })
    e = Env({"COMMIT" : "4321"})
    match, scm = o.mangle(self.scm, e)
    self.assertEqual(scm, {
        'scm' : "git",
        'url' : "git@git.com:foo/bar.git",
        'branch' : "develop",
        'commit' : "4321"
    })