public void testNegate() {
Fraction f = null;
f = new Fraction(50, 75);
f = f.negate();
assertEquals(-2, f.getNumerator());
assertEquals(3, f.getDenominator());
f = new Fraction(-50, 75);
f = f.negate();
assertEquals(2, f.getNumerator());
assertEquals(3, f.getDenominator());
// large values
f = new Fraction(Integer.MAX_VALUE - 1, Integer.MAX_VALUE);
f = f.negate();
assertEquals(Integer.MIN_VALUE + 2, f.getNumerator());
assertEquals(Integer.MAX_VALUE, f.getDenominator());
f = new Fraction(Integer.MIN_VALUE, 1);
try {
f = f.negate();
fail("expecting ArithmeticException");
} catch (ArithmeticException ex) {
}
}
public void testReciprocal() {
Fraction f = null;
f = new Fraction(50, 75);
f = f.reciprocal();
assertEquals(3, f.getNumerator());
assertEquals(2, f.getDenominator());
f = new Fraction(4, 3);
f = f.reciprocal();
assertEquals(3, f.getNumerator());
assertEquals(4, f.getDenominator());
f = new Fraction(-15, 47);
f = f.reciprocal();
assertEquals(-47, f.getNumerator());
assertEquals(15, f.getDenominator());
f = new Fraction(0, 3);
try {
f = f.reciprocal();
fail("expecting ArithmeticException");
} catch (ArithmeticException ex) {
}
// large values
f = new Fraction(Integer.MAX_VALUE, 1);
f = f.reciprocal();
assertEquals(1, f.getNumerator());
assertEquals(Integer.MAX_VALUE, f.getDenominator());
}
public void testDivide() {
Fraction a = new Fraction(1, 2);
Fraction b = new Fraction(2, 3);
assertFraction(1, 1, a.divide(a));
assertFraction(3, 4, a.divide(b));
assertFraction(4, 3, b.divide(a));
assertFraction(1, 1, b.divide(b));
Fraction f1 = new Fraction(3, 5);
Fraction f2 = Fraction.ZERO;
try {
f1.divide(f2);
fail("expecting ArithmeticException");
} catch (ArithmeticException ex) {
}
f1 = new Fraction(0, 5);
f2 = new Fraction(2, 7);
Fraction f = f1.divide(f2);
assertSame(Fraction.ZERO, f);
f1 = new Fraction(2, 7);
f2 = Fraction.ONE;
f = f1.divide(f2);
assertEquals(2, f.getNumerator());
assertEquals(7, f.getDenominator());
f1 = new Fraction(1, Integer.MAX_VALUE);
f = f1.divide(f1);
assertEquals(1, f.getNumerator());
assertEquals(1, f.getDenominator());
f1 = new Fraction(Integer.MIN_VALUE, Integer.MAX_VALUE);
f2 = new Fraction(1, Integer.MAX_VALUE);
f = f1.divide(f2);
assertEquals(Integer.MIN_VALUE, f.getNumerator());
assertEquals(1, f.getDenominator());
try {
f.divide(null);
fail("IllegalArgumentException");
} catch (IllegalArgumentException ex) {
}
try {
f1 = new Fraction(1, Integer.MAX_VALUE);
f = f1.divide(f1.reciprocal()); // should overflow
fail("expecting ArithmeticException");
} catch (ArithmeticException ex) {
}
try {
f1 = new Fraction(1, -Integer.MAX_VALUE);
f = f1.divide(f1.reciprocal()); // should overflow
fail("expecting ArithmeticException");
} catch (ArithmeticException ex) {
}
}
public void testMultiply() {
Fraction a = new Fraction(1, 2);
Fraction b = new Fraction(2, 3);
assertFraction(1, 4, a.multiply(a));
assertFraction(1, 3, a.multiply(b));
assertFraction(1, 3, b.multiply(a));
assertFraction(4, 9, b.multiply(b));
Fraction f1 = new Fraction(Integer.MAX_VALUE, 1);
Fraction f2 = new Fraction(Integer.MIN_VALUE, Integer.MAX_VALUE);
Fraction f = f1.multiply(f2);
assertEquals(Integer.MIN_VALUE, f.getNumerator());
assertEquals(1, f.getDenominator());
try {
f.multiply(null);
fail("expecting IllegalArgumentException");
} catch (IllegalArgumentException ex) {
}
}
public void testSubtract() {
Fraction a = new Fraction(1, 2);
Fraction b = new Fraction(2, 3);
assertFraction(0, 1, a.subtract(a));
assertFraction(-1, 6, a.subtract(b));
assertFraction(1, 6, b.subtract(a));
assertFraction(0, 1, b.subtract(b));
Fraction f = new Fraction(1, 1);
try {
f.subtract(null);
fail("expecting IllegalArgumentException");
} catch (IllegalArgumentException ex) {
}
// if this fraction is subtracted naively, it will overflow.
// check that it doesn't.
Fraction f1 = new Fraction(1, 32768 * 3);
Fraction f2 = new Fraction(1, 59049);
f = f1.subtract(f2);
assertEquals(-13085, f.getNumerator());
assertEquals(1934917632, f.getDenominator());
f1 = new Fraction(Integer.MIN_VALUE, 3);
f2 = new Fraction(1, 3).negate();
f = f1.subtract(f2);
assertEquals(Integer.MIN_VALUE + 1, f.getNumerator());
assertEquals(3, f.getDenominator());
f1 = new Fraction(Integer.MAX_VALUE, 1);
f2 = Fraction.ONE;
f = f1.subtract(f2);
assertEquals(Integer.MAX_VALUE - 1, f.getNumerator());
assertEquals(1, f.getDenominator());
try {
f1 = new Fraction(1, Integer.MAX_VALUE);
f2 = new Fraction(1, Integer.MAX_VALUE - 1);
f = f1.subtract(f2);
fail("expecting ArithmeticException"); // should overflow
} catch (ArithmeticException ex) {
}
// denominator should not be a multiple of 2 or 3 to trigger overflow
f1 = new Fraction(Integer.MIN_VALUE, 5);
f2 = new Fraction(1, 5);
try {
f = f1.subtract(f2); // should overflow
fail("expecting ArithmeticException but got: " + f.toString());
} catch (ArithmeticException ex) {
}
try {
f = new Fraction(Integer.MIN_VALUE, 1);
f = f.subtract(Fraction.ONE);
fail("expecting ArithmeticException");
} catch (ArithmeticException ex) {
}
try {
f = new Fraction(Integer.MAX_VALUE, 1);
f = f.subtract(Fraction.ONE.negate());
fail("expecting ArithmeticException");
} catch (ArithmeticException ex) {
}
f1 = new Fraction(3, 327680);
f2 = new Fraction(2, 59049);
try {
f = f1.subtract(f2); // should overflow
fail("expecting ArithmeticException but got: " + f.toString());
} catch (ArithmeticException ex) {
}
}
public void testAdd() {
Fraction a = new Fraction(1, 2);
Fraction b = new Fraction(2, 3);
assertFraction(1, 1, a.add(a));
assertFraction(7, 6, a.add(b));
assertFraction(7, 6, b.add(a));
assertFraction(4, 3, b.add(b));
Fraction f1 = new Fraction(Integer.MAX_VALUE - 1, 1);
Fraction f2 = Fraction.ONE;
Fraction f = f1.add(f2);
assertEquals(Integer.MAX_VALUE, f.getNumerator());
assertEquals(1, f.getDenominator());
f1 = new Fraction(-1, 13 * 13 * 2 * 2);
f2 = new Fraction(-2, 13 * 17 * 2);
f = f1.add(f2);
assertEquals(13 * 13 * 17 * 2 * 2, f.getDenominator());
assertEquals(-17 - 2 * 13 * 2, f.getNumerator());
try {
f.add(null);
fail("expecting IllegalArgumentException");
} catch (IllegalArgumentException ex) {
}
// if this fraction is added naively, it will overflow.
// check that it doesn't.
f1 = new Fraction(1, 32768 * 3);
f2 = new Fraction(1, 59049);
f = f1.add(f2);
assertEquals(52451, f.getNumerator());
assertEquals(1934917632, f.getDenominator());
f1 = new Fraction(Integer.MIN_VALUE, 3);
f2 = new Fraction(1, 3);
f = f1.add(f2);
assertEquals(Integer.MIN_VALUE + 1, f.getNumerator());
assertEquals(3, f.getDenominator());
f1 = new Fraction(Integer.MAX_VALUE - 1, 1);
f2 = Fraction.ONE;
f = f1.add(f2);
assertEquals(Integer.MAX_VALUE, f.getNumerator());
assertEquals(1, f.getDenominator());
try {
f = f.add(Fraction.ONE); // should overflow
fail("expecting ArithmeticException but got: " + f.toString());
} catch (ArithmeticException ex) {
}
// denominator should not be a multiple of 2 or 3 to trigger overflow
f1 = new Fraction(Integer.MIN_VALUE, 5);
f2 = new Fraction(-1, 5);
try {
f = f1.add(f2); // should overflow
fail("expecting ArithmeticException but got: " + f.toString());
} catch (ArithmeticException ex) {
}
try {
f = new Fraction(-Integer.MAX_VALUE, 1);
f = f.add(f);
fail("expecting ArithmeticException");
} catch (ArithmeticException ex) {
}
try {
f = new Fraction(-Integer.MAX_VALUE, 1);
f = f.add(f);
fail("expecting ArithmeticException");
} catch (ArithmeticException ex) {
}
f1 = new Fraction(3, 327680);
f2 = new Fraction(2, 59049);
try {
f = f1.add(f2); // should overflow
fail("expecting ArithmeticException but got: " + f.toString());
} catch (ArithmeticException ex) {
}
}
private void assertFraction(int expectedNumerator, int expectedDenominator, Fraction actual) {
assertEquals(expectedNumerator, actual.getNumerator());
assertEquals(expectedDenominator, actual.getDenominator());
}
private String fractionToString(Fraction fraction) {
return fraction.getDenominator() == 1
? Integer.toString(fraction.getNumerator())
: FractionFormat.getImproperInstance().format(fraction);
}
