def METHOD_NAME(self):
    """Same input should yield same digest"""
    s1 = CoreCheckoutStep(nullPkg, ("script", "digest", [], []), [],
        Env({"a" : "asdf", "q": "qwer" }), Env({ "a" : "asdf" }))
    s2 = CoreCheckoutStep(nullPkg, ("script", "digest", [], []), [],
        Env({"a" : "asdf", "q": "qwer" }), Env({ "a" : "asdf" }))
    assert s1.variantId == s2.variantId