t.Run("case=custom-lifespans-active-opaque", func(t *testing.T) {
            c, conf := newOAuth2Client(t, reg, testhelpers.NewCallbackURL(t, "callback", testhelpers.HTTPServerNotImplementedHandler))
            ls := testhelpers.TestLifespans
            ls.AuthorizationCodeGrantAccessTokenLifespan = x.NullDuration{Valid: true, Duration: 6 * time.Second}
            testhelpers.UpdateClientTokenLifespans(