@Test
public void testCart() {

    Assert.assertEquals(54.654, c1.getRe(), 0);
    Assert.assertEquals(7.321, c1.getIm(), 0);
    Assert.assertSame(Complex.ZERO, cart(0, 0));
    Assert.assertSame(Complex.ONE, cart(1, 0));
    Assert.assertSame(Complex.NEG_ONE, cart(-1, 0));
    Assert.assertSame(Complex.I, cart(0, 1));
    Assert.assertSame(Complex.NEG_I, cart(0, -1));
    Assert.assertNotSame(cart(54.654, 7.321), c1);
}