// Relies on the correctness of log10(BigInteger, {HALF_UP,HALF_DOWN}).
@GwtIncompatible // TODO
public void testLog10HalfEven() {
for (BigInteger x : POSITIVE_BIGINTEGER_CANDIDATES) {
int halfEven = BigIntegerMath.log10(x, HALF_EVEN);
// Now figure out what rounding mode we should behave like (it depends if FLOOR was
// odd/even).
boolean floorWasEven = (BigIntegerMath.log10(x, FLOOR) & 1) == 0;
assertEquals(BigIntegerMath.log10(x, floorWasEven ? HALF_DOWN : HALF_UP), halfEven);
}
}
// Relies on the correctness of log10(BigInteger, FLOOR).
@GwtIncompatible // TODO
public void testLog10Exact() {
for (BigInteger x : POSITIVE_BIGINTEGER_CANDIDATES) {
int logFloor = BigIntegerMath.log10(x, FLOOR);
boolean expectSuccess = TEN.pow(logFloor).equals(x);
try {
assertEquals(logFloor, BigIntegerMath.log10(x, UNNECESSARY));
assertTrue(expectSuccess);
} catch (ArithmeticException e) {
assertFalse(expectSuccess);
}
}
}
@GwtIncompatible // TODO
public void testLog10TrivialOnPowerOf10() {
BigInteger x = BigInteger.TEN.pow(100);
for (RoundingMode mode : ALL_ROUNDING_MODES) {
assertEquals(100, BigIntegerMath.log10(x, mode));
}
}
@GwtIncompatible // TODO
public void testLog10Ceiling() {
for (BigInteger x : POSITIVE_BIGINTEGER_CANDIDATES) {
for (RoundingMode mode : asList(CEILING, UP)) {
int result = BigIntegerMath.log10(x, mode);
assertTrue(TEN.pow(result).compareTo(x) >= 0);
assertTrue(result == 0 || TEN.pow(result - 1).compareTo(x) < 0);
}
}
}
@GwtIncompatible // TODO
public void testLog10Floor() {
for (BigInteger x : POSITIVE_BIGINTEGER_CANDIDATES) {
for (RoundingMode mode : asList(FLOOR, DOWN)) {
int result = BigIntegerMath.log10(x, mode);
assertTrue(TEN.pow(result).compareTo(x) <= 0);
assertTrue(TEN.pow(result + 1).compareTo(x) > 0);
}
}
}
@GwtIncompatible // TODO
public void testLog10NegativeAlwaysThrows() {
for (RoundingMode mode : ALL_ROUNDING_MODES) {
try {
BigIntegerMath.log10(BigInteger.valueOf(-1), mode);
fail("Expected IllegalArgumentException");
} catch (IllegalArgumentException expected) {
}
}
}
@GwtIncompatible // TODO
public void testLog10HalfDown() {
for (BigInteger x : POSITIVE_BIGINTEGER_CANDIDATES) {
int result = BigIntegerMath.log10(x, HALF_DOWN);
BigInteger x2 = x.pow(2);
// x^2 <= 10^(2 * result + 1), or else we would have rounded up
assertTrue(TEN.pow(2 * result + 1).compareTo(x2) >= 0);
// x^2 > 10^(2 * result - 1), or else we would have rounded down
assertTrue(result == 0 || TEN.pow(2 * result - 1).compareTo(x2) < 0);
}
}
