@Test
 public void test_massInLbs() {
   m1 = Values.massInKg(1);
   m2 = Values.massInLbs(2.20462262);
   m3 = Values.massInLbs(1102.31131);
   m4 = Values.massInLbs(5511.55655);
   m5 = Values.massInLbs(1104.51593262);
   m6 = Values.massInLbs(4409.24524);
   m7 = Values.ZERO_MASS;
   assertEquals(m4, m3.mul(5));
   assertEquals(m3.kg(), m4.div(5).kg(), 0.01);
   assertEquals(m5.kg(), m1.add(m3).kg(), 4d);
   assertEquals(m6.kg(), m4.sub(m3).kg(), 0.01);
   assertTrue(m7.isZero());
   assertTrue("500,00".equals(m3.toString()));
   assertEquals(m1, m2);
 }
 @Test
 public void test_massInKg() {
   m1 = Values.massInKg(1);
   m2 = Values.massInKg(1);
   m3 = Values.massInKg(500);
   m4 = Values.massInKg(2500);
   m5 = Values.massInKg(501);
   m6 = Values.massInKg(2000);
   m7 = Values.ZERO_MASS;
   assertEquals(m1, m2);
   assertEquals(m4, m3.mul(5));
   assertEquals(m3, m4.div(5));
   assertEquals(m5, m1.add(m3));
   assertEquals(m6, m4.sub(m3));
   assertTrue(m7.isZero());
   assertTrue("500,00".equals(m3.toString()));
   assertEquals("500,00", m3.toString());
 }
 @Test
 public void test_massInG() {
   m1 = Values.massInKg(1);
   m2 = Values.massInG(1000);
   m3 = Values.massInG(500);
   m4 = Values.massInG(2500);
   m5 = Values.massInG(1500);
   m6 = Values.massInG(2000);
   assertEquals(m4, m3.mul(5));
   assertEquals(m3, m4.div(5));
   assertEquals(m5, m1.add(m3));
   assertEquals(m6, m4.sub(m3));
   assertTrue(!m6.isZero());
   assertTrue("0,50".equals(m3.toString()));
   assertEquals(m1, m2);
 }