public void testFactorial() {
for (int i = 0; i <= DoubleMath.MAX_FACTORIAL; i++) {
double actual = BigIntegerMath.factorial(i).doubleValue();
double result = DoubleMath.factorial(i);
assertEquals(actual, result, Math.ulp(actual));
}
}
public void testFactorialNegative() {
for (int n : NEGATIVE_INTEGER_CANDIDATES) {
try {
DoubleMath.factorial(n);
fail("Expected IllegalArgumentException");
} catch (IllegalArgumentException expected) {
}
}
}
public void testFactorialTooHigh() {
assertEquals(Double.POSITIVE_INFINITY, DoubleMath.factorial(DoubleMath.MAX_FACTORIAL + 1));
assertEquals(Double.POSITIVE_INFINITY, DoubleMath.factorial(DoubleMath.MAX_FACTORIAL + 20));
}