@Test public void addAtomsResize() {

    Graph g = new Graph(2);
    assertThat(g.addAtom(mock(Atom.class)), is(0));
    assertThat(g.addAtom(mock(Atom.class)), is(1));
    assertThat(g.addAtom(mock(Atom.class)), is(2));
    assertThat(g.addAtom(mock(Atom.class)), is(3));
    assertThat(g.addAtom(mock(Atom.class)), is(4));
}