@Test
    public void testParseOnSpringsToInputs() {
        parser.parse("shoulder 0 1\n"
                + "input 0 2\n"
                + "input 0 10\n"
                + "elbow 0 11\n"
                + "input 0 12\n"
                + "input 0 20\n"
                + "hand 0 21");
        List<Mass> masses = parser.graph.getMasses();
        assertMass(masses.get(0), 0, 1, SHOULDER);
        assertMass(masses.get(1), 0, 2, INPUT);
        assertMass(masses.get(2), 0, 10, INPUT);
        assertMass(masses.get(3), 0, 11, ELBOW);
        assertMass(masses.get(4), 0, 12, INPUT);
        assertMass(masses.get(5), 0, 20, INPUT);
        assertMass(masses.get(6), 0, 21, HAND);
        assertMass(masses.get(7), 0, 1, ARM_SEGMENT);
        assertMass(masses.get(8), 0, 11, ARM_SEGMENT);
        assertEquals(9, masses.size());

        List<Spring> springs = parser.graph.getSprings();
        assertSpring(springs.get(0), masses.get(0), masses.get(7), ROBOT_ARM_BASE_CONSTRAINT);
        assertSpring(springs.get(1), masses.get(3), masses.get(7), FIXED_CONSTRAINT);
        assertSpring(springs.get(2), masses.get(1), masses.get(7), FIXED_CONSTRAINT);
        assertSpring(springs.get(3), masses.get(2), masses.get(7), FIXED_CONSTRAINT);
        assertSpring(springs.get(4), masses.get(3), masses.get(8), FIXED_CONSTRAINT);
        assertSpring(springs.get(5), masses.get(6), masses.get(8), FIXED_CONSTRAINT);
        assertSpring(springs.get(6), masses.get(4), masses.get(8), FIXED_CONSTRAINT);
        assertSpring(springs.get(7), masses.get(5), masses.get(8), FIXED_CONSTRAINT);
        assertSpring(springs.get(8), masses.get(7), masses.get(8), ROBOT_ARM_JOINT_CONSTRAINT);
        assertEquals(9, springs.size());
    }