@Test public void toExplicitEdge() {

    Graph g = new Graph(2);
    Atom u = Mockito.mock(Atom.class);
    Atom v = Mockito.mock(Atom.class);
    Mockito.when(u.aromatic()).thenReturn(false);
    Mockito.when(v.aromatic()).thenReturn(false);
    g.addAtom(u);
    g.addAtom(v);
    Edge e = new Edge(0, 1, IMPLICIT);
    Assert.assertThat(ImplicitToExplicit.toExplicitEdge(g, e),
                      CoreMatchers.is(CoreMatchers.not(CoreMatchers
                                                               .sameInstance(e))));
    Assert.assertThat(ImplicitToExplicit.toExplicitEdge(g, e),
                      CoreMatchers.is(new Edge(0, 1, SINGLE)));
}