@Test
    public void testParseOnMassTypesAndSprings() {
        parser.parse("shoulder 0 1\n"
                + "elbow 0 11\n"
                + "hand 0 21");
        List<Mass> masses = parser.graph.getMasses();
        assertMass(masses.get(0), 0, 1, SHOULDER);
        assertMass(masses.get(1), 0, 11, ELBOW);
        assertMass(masses.get(2), 0, 21, HAND);
        assertEquals(3, masses.size());

        List<Spring> springs = parser.graph.getSprings();
        assertEquals(0, springs.size());
    }