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BAEL-640: Guide to Mathematical Operations with Guava (#1390)

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* Guava IntMath tests

* Guava DoubleMath test

* break down testDoubleMath()
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Diane Duan 2017-04-03 03:28:36 +08:00 committed by adamd1985
parent d361c91ed3
commit 54615ddd11
1 changed files with 192 additions and 0 deletions
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guava/src/test/java/org/baeldung/guava/GuavaMathTest.java Normal file
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package org.baeldung.guava;
import com.google.common.math.DoubleMath;
import com.google.common.math.IntMath;
import org.junit.Rule;
import org.junit.Test;
import org.junit.rules.ExpectedException;
import java.math.BigInteger;
import java.math.RoundingMode;
import static org.hamcrest.core.IsEqual.equalTo;
import static org.junit.Assert.assertFalse;
import static org.junit.Assert.assertThat;
import static org.junit.Assert.assertTrue;
public class GuavaMathTest {
@Test
public void testIntMathAdd() {
try {
IntMath.checkedAdd(Integer.MAX_VALUE, 1);
assertTrue(false);
} catch (ArithmeticException e) {
assertTrue(true);
}
try {
IntMath.checkedAdd(Integer.MIN_VALUE, -1);
assertTrue(false);
} catch (ArithmeticException e) {
assertTrue(true);
}
int result1 = IntMath.checkedAdd(2, 1);
assertThat(result1, equalTo(3));
int result2 = IntMath.saturatedAdd(Integer.MAX_VALUE, 100);
assertThat(result2, equalTo(Integer.MAX_VALUE));
int result3 = IntMath.saturatedAdd(Integer.MIN_VALUE, -100);
assertThat(result3, equalTo(Integer.MIN_VALUE));
}
@Test
public void testIntMathSubtract() {
try {
IntMath.checkedSubtract(Integer.MIN_VALUE, 1);
assertTrue(false);
} catch (ArithmeticException e) {
assertTrue(true);
}
try {
IntMath.checkedSubtract(Integer.MAX_VALUE, -1);
assertTrue(false);
} catch (ArithmeticException e) {
assertTrue(true);
};
int result1 = IntMath.checkedSubtract(200, 100);
assertThat(result1, equalTo(100));
int result2 = IntMath.saturatedSubtract(Integer.MIN_VALUE, 1);
assertThat(result2, equalTo(Integer.MIN_VALUE));
int result3 = IntMath.saturatedSubtract(Integer.MAX_VALUE, -1);
assertThat(result3, equalTo(Integer.MAX_VALUE));
}
@Test
public void testIntMathMultiply() {
try {
IntMath.checkedMultiply(Integer.MAX_VALUE, 2);
assertTrue(false);
} catch (ArithmeticException e) {
assertTrue(true);
}
try {
IntMath.checkedMultiply(Integer.MIN_VALUE, 2);
assertTrue(false);
} catch (ArithmeticException e) {
assertTrue(true);
}
int result1 = IntMath.checkedMultiply(21, 3);
assertThat(result1, equalTo(63));
int result2 = IntMath.saturatedMultiply(Integer.MAX_VALUE, 2);
assertThat(result2, equalTo(Integer.MAX_VALUE));
int result3 = IntMath.saturatedMultiply(Integer.MIN_VALUE, 2);
assertThat(result3, equalTo(Integer.MIN_VALUE));
}
@Test
public void testIntMathPow() {
try {
IntMath.checkedPow(Integer.MAX_VALUE, 2);
assertTrue(false);
} catch (ArithmeticException e) {
assertTrue(true);
}
try {
IntMath.checkedPow(Integer.MIN_VALUE, 3);
assertTrue(false);
} catch (ArithmeticException e) {
assertTrue(true);
}
int result1 = IntMath.saturatedPow(3, 3);
assertThat(result1, equalTo(27));
int result2 = IntMath.saturatedPow(Integer.MAX_VALUE, 2);
assertThat(result2, equalTo(Integer.MAX_VALUE));
int result3 = IntMath.saturatedPow(Integer.MIN_VALUE, 3);
assertThat(result3, equalTo(Integer.MIN_VALUE));
}
@Test
public void testIntMathRound() {
int result1 = IntMath.divide(3, 2, RoundingMode.DOWN);
assertThat(result1, equalTo(1));
int result2 = IntMath.divide(3, 2, RoundingMode.UP);
assertThat(result2, equalTo(2));
int result3 = IntMath.log2(5, RoundingMode.FLOOR);
assertThat(result3, equalTo(2));
int result4 = IntMath.log2(5, RoundingMode.CEILING);
assertThat(result4, equalTo(3));
int result5 = IntMath.log10(11, RoundingMode.HALF_UP);
assertThat(result5, equalTo(1));
int result6 = IntMath.sqrt(4, RoundingMode.UNNECESSARY);
assertThat(result6, equalTo(2));
try {
IntMath.sqrt(5, RoundingMode.UNNECESSARY);
assertTrue(false);
} catch (ArithmeticException e) {
assertTrue(true);
}
}
@Test
public void testIntMathAdditionalFunctions() {
int result1 = IntMath.gcd(15, 20);
assertThat(result1, equalTo(5));
int result2 = IntMath.mod(8, 3);
assertThat(result2, equalTo(2));
boolean result3 = IntMath.isPowerOfTwo(8);
assertTrue(result3);
boolean result4 = IntMath.isPowerOfTwo(9);
assertFalse(result4);
int result5 = IntMath.factorial(4);
assertThat(result5, equalTo(24));
int result6 = IntMath.binomial(7, 3);
assertThat(result6, equalTo(35));
}
@Test
public void should_detect_integer() {
boolean result1 = DoubleMath.isMathematicalInteger(2.0);
assertThat(result1, equalTo(true));
boolean result2 = DoubleMath.isMathematicalInteger(2.1);
assertThat(result2, equalTo(false));
}
@Test
public void should_round_to_integer_types() {
int result3 = DoubleMath.roundToInt(2.5, RoundingMode.DOWN);
assertThat(result3, equalTo(2));
long result4 = DoubleMath.roundToLong(2.5, RoundingMode.HALF_UP);
assertThat(result4, equalTo(3L));
BigInteger result5 = DoubleMath.roundToBigInteger(2.5, RoundingMode.UP);
assertThat(result5, equalTo(new BigInteger("3")));
}
@Test
public void should_calculate_log_2() {
int result6 = DoubleMath.log2(10, RoundingMode.UP);
assertThat(result6, equalTo(4));
}
}