@Test
public void testGetFirstMapping() {

    IAtom atomSource = new Atom("R");
    IAtom atomTarget = new Atom("R");
    IAtomContainer source = new AtomContainer();
    source.addAtom(atomSource);
    IAtomContainer target = new AtomContainer();
    target.addAtom(atomTarget);
    boolean removeHydrogen = false;
    SingleMappingHandler instance = new SingleMappingHandler(removeHydrogen);
    MolHandler mol1 = new MolHandler(source, true, true);
    MolHandler mol2 = new MolHandler(target, true, true);
    instance.set(mol1, mol2);
    instance.searchMCS(true);
    assertNotNull(instance.getFirstMapping());
}