@Test public void toExplicitEdge_NonImplicitIdentity() {

    Graph g = new Graph(0);
    for (Bond b : Bond.values()) {
        if (b != IMPLICIT) {
            Edge e = new Edge(0, 1, SINGLE);
            Assert.assertThat(ImplicitToExplicit
                                      .toExplicitEdge(g, e), CoreMatchers
                                      .is(CoreMatchers.sameInstance(e)));
        }
    }
}