| import org.junit.Test; |
| import static org.junit.Assert.*; |
|
|
| public class FractionTest { |
| @Test public void reducesAndNormalizesSign() { |
| Fraction f = new Fraction(4, -8); |
| assertEquals(-1, f.numerator()); |
| assertEquals(2, f.denominator()); |
| assertEquals("-1/2", f.toString()); |
| } |
| @Test public void wholeNumberToString() { assertEquals("3", new Fraction(6, 2).toString()); } |
| @Test public void zeroIsZeroOverOne() { |
| Fraction z = new Fraction(0, 5); |
| assertEquals(0, z.numerator()); |
| assertEquals(1, z.denominator()); |
| } |
| @Test(expected = ArithmeticException.class) public void zeroDenominator() { new Fraction(1, 0); } |
| @Test public void add() { assertEquals(new Fraction(5, 6), new Fraction(1, 2).add(new Fraction(1, 3))); } |
| @Test public void subtract() { assertEquals(new Fraction(1, 6), new Fraction(1, 2).subtract(new Fraction(1, 3))); } |
| @Test public void multiply() { assertEquals(new Fraction(1, 6), new Fraction(1, 2).multiply(new Fraction(1, 3))); } |
| @Test public void divide() { assertEquals(new Fraction(3, 2), new Fraction(1, 2).divide(new Fraction(1, 3))); } |
| @Test(expected = ArithmeticException.class) public void divideByZero() { new Fraction(1, 2).divide(new Fraction(0, 3)); } |
| @Test public void toDouble() { assertEquals(0.75, new Fraction(3, 4).toDouble(), 1e-12); } |
| @Test public void compare() { |
| assertTrue(new Fraction(1, 3).compareTo(new Fraction(1, 2)) < 0); |
| assertTrue(new Fraction(2, 3).compareTo(new Fraction(1, 2)) > 0); |
| assertEquals(0, new Fraction(2, 4).compareTo(new Fraction(1, 2))); |
| } |
| @Test public void equalsAndHashCode() { |
| Fraction a = new Fraction(2, 4), b = new Fraction(1, 2); |
| assertEquals(a, b); |
| assertEquals(a.hashCode(), b.hashCode()); |
| assertEquals(a, a); |
| assertNotEquals(a, new Fraction(1, 3)); |
| assertNotEquals(a, "1/2"); |
| } |
| } |
|
|
