/*
    * Copyright (C) 2011 The Guava Authors
    *
    * Licensed under the Apache License, Version 2.0 (the "License");
    * you may not use this file except in compliance with the License.
    * You may obtain a copy of the License at
    *
    * http://www.apache.org/licenses/LICENSE-2.0
    *
   * Unless required by applicable law or agreed to in writing, software
   * distributed under the License is distributed on an "AS IS" BASIS,
   * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
   * See the License for the specific language governing permissions and
   * limitations under the License.
   */
  
  package com.google.common.math;
  
  import static com.google.common.math.MathTesting.ALL_DOUBLE_CANDIDATES;
  import static com.google.common.math.MathTesting.ALL_ROUNDING_MODES;
  import static com.google.common.math.MathTesting.ALL_SAFE_ROUNDING_MODES;
  import static com.google.common.math.MathTesting.DOUBLE_CANDIDATES_EXCEPT_NAN;
  import static com.google.common.math.MathTesting.FINITE_DOUBLE_CANDIDATES;
  import static com.google.common.math.MathTesting.FRACTIONAL_DOUBLE_CANDIDATES;
  import static com.google.common.math.MathTesting.INFINITIES;
  import static com.google.common.math.MathTesting.INTEGRAL_DOUBLE_CANDIDATES;
  import static com.google.common.math.MathTesting.NEGATIVE_INTEGER_CANDIDATES;
  import static com.google.common.math.MathTesting.POSITIVE_FINITE_DOUBLE_CANDIDATES;
  import static java.math.RoundingMode.CEILING;
  import static java.math.RoundingMode.DOWN;
  import static java.math.RoundingMode.FLOOR;
  import static java.math.RoundingMode.HALF_DOWN;
  import static java.math.RoundingMode.HALF_EVEN;
  import static java.math.RoundingMode.HALF_UP;
  import static java.math.RoundingMode.UNNECESSARY;
  import static java.math.RoundingMode.UP;
  import static java.util.Arrays.asList;
  
  import com.google.common.annotations.GwtCompatible;
  import com.google.common.annotations.GwtIncompatible;
  import com.google.common.collect.ImmutableList;
  import com.google.common.collect.Iterables;
  import com.google.common.primitives.Doubles;
  import com.google.common.testing.NullPointerTester;
  
  import junit.framework.TestCase;
  
  import java.math.BigDecimal;
  import java.math.BigInteger;
  import java.math.RoundingMode;
  import java.util.Arrays;
  import java.util.List;
  
  /**
   * Tests for {@code DoubleMath}.
   *
   * @author Louis Wasserman
   */
  @GwtCompatible(emulated = true)
  public class DoubleMathTest extends TestCase {
  
    private static final BigDecimal MAX_INT_AS_BIG_DECIMAL = BigDecimal.valueOf(Integer.MAX_VALUE);
    private static final BigDecimal MIN_INT_AS_BIG_DECIMAL = BigDecimal.valueOf(Integer.MIN_VALUE);
  
    private static final BigDecimal MAX_LONG_AS_BIG_DECIMAL = BigDecimal.valueOf(Long.MAX_VALUE);
    private static final BigDecimal MIN_LONG_AS_BIG_DECIMAL = BigDecimal.valueOf(Long.MIN_VALUE);
  
    public void testConstantsMaxFactorial() {
      BigInteger maxDoubleValue = BigDecimal.valueOf(Double.MAX_VALUE).toBigInteger();
      assertTrue(BigIntegerMath.factorial(DoubleMath.MAX_FACTORIAL).compareTo(maxDoubleValue) <= 0);
      assertTrue(
          BigIntegerMath.factorial(DoubleMath.MAX_FACTORIAL + 1).compareTo(maxDoubleValue) > 0);
    }
  
    public void testConstantsEverySixteenthFactorial() {
      for (int i = 0, n = 0; n <= DoubleMath.MAX_FACTORIAL; i++, n += 16) {
        assertEquals(
            BigIntegerMath.factorial(n).doubleValue(), DoubleMath.everySixteenthFactorial[i]);
      }
    }
  
    @GwtIncompatible("DoubleMath.roundToInt(double, RoundingMode)")
    public void testRoundIntegralDoubleToInt() {
      for (double d : INTEGRAL_DOUBLE_CANDIDATES) {
        for (RoundingMode mode : ALL_SAFE_ROUNDING_MODES) {
          BigDecimal expected = new BigDecimal(d).setScale(0, mode);
          boolean isInBounds = expected.compareTo(MAX_INT_AS_BIG_DECIMAL) <= 0
              & expected.compareTo(MIN_INT_AS_BIG_DECIMAL) >= 0;
  
          try {
            assertEquals(expected.intValue(), DoubleMath.roundToInt(d, mode));
            assertTrue(isInBounds);
          } catch (ArithmeticException e) {
            assertFalse(isInBounds);
          }
        }
      }
    }
  
   @GwtIncompatible("DoubleMath.roundToInt(double, RoundingMode)")
   public void testRoundFractionalDoubleToInt() {
     for (double d : FRACTIONAL_DOUBLE_CANDIDATES) {
       for (RoundingMode mode : ALL_SAFE_ROUNDING_MODES) {
         BigDecimal expected = new BigDecimal(d).setScale(0, mode);
         boolean isInBounds = expected.compareTo(MAX_INT_AS_BIG_DECIMAL) <= 0
             & expected.compareTo(MIN_INT_AS_BIG_DECIMAL) >= 0;
 
         try {
           assertEquals(expected.intValue(), DoubleMath.roundToInt(d, mode));
           assertTrue(isInBounds);
         } catch (ArithmeticException e) {
           assertFalse(isInBounds);
         }
       }
     }
   }
 
   @GwtIncompatible("DoubleMath.roundToInt(double, RoundingMode)")
   public void testRoundExactIntegralDoubleToInt() {
     for (double d : INTEGRAL_DOUBLE_CANDIDATES) {
       BigDecimal expected = new BigDecimal(d).setScale(0, UNNECESSARY);
       boolean isInBounds = expected.compareTo(MAX_INT_AS_BIG_DECIMAL) <= 0
           & expected.compareTo(MIN_INT_AS_BIG_DECIMAL) >= 0;
 
       try {
         assertEquals(expected.intValue(), DoubleMath.roundToInt(d, UNNECESSARY));
         assertTrue(isInBounds);
       } catch (ArithmeticException e) {
         assertFalse(isInBounds);
       }
     }
   }
 
   @GwtIncompatible("DoubleMath.roundToInt(double, RoundingMode)")
   public void testRoundExactFractionalDoubleToIntFails() {
     for (double d : FRACTIONAL_DOUBLE_CANDIDATES) {
       try {
         DoubleMath.roundToInt(d, UNNECESSARY);
         fail("Expected ArithmeticException");
       } catch (ArithmeticException expected) {}
     }
   }
 
   @GwtIncompatible("DoubleMath.roundToInt(double, RoundingMode)")
   public void testRoundNaNToIntAlwaysFails() {
     for (RoundingMode mode : ALL_ROUNDING_MODES) {
       try {
         DoubleMath.roundToInt(Double.NaN, mode);
         fail("Expected ArithmeticException");
       } catch (ArithmeticException expected) {}
     }
   }
 
   @GwtIncompatible("DoubleMath.roundToInt(double, RoundingMode)")
   public void testRoundInfiniteToIntAlwaysFails() {
     for (RoundingMode mode : ALL_ROUNDING_MODES) {
       try {
         DoubleMath.roundToInt(Double.POSITIVE_INFINITY, mode);
         fail("Expected ArithmeticException");
       } catch (ArithmeticException expected) {}
       try {
         DoubleMath.roundToInt(Double.NEGATIVE_INFINITY, mode);
         fail("Expected ArithmeticException");
       } catch (ArithmeticException expected) {}
     }
   }
 
   @GwtIncompatible("DoubleMath.roundToLong(double, RoundingMode)")
   public void testRoundIntegralDoubleToLong() {
     for (double d : INTEGRAL_DOUBLE_CANDIDATES) {
       for (RoundingMode mode : ALL_SAFE_ROUNDING_MODES) {
         BigDecimal expected = new BigDecimal(d).setScale(0, mode);
         boolean isInBounds = expected.compareTo(MAX_LONG_AS_BIG_DECIMAL) <= 0
             & expected.compareTo(MIN_LONG_AS_BIG_DECIMAL) >= 0;
 
         try {
           assertEquals(expected.longValue(), DoubleMath.roundToLong(d, mode));
           assertTrue(isInBounds);
         } catch (ArithmeticException e) {
           assertFalse(isInBounds);
         }
       }
     }
   }
 
   @GwtIncompatible("DoubleMath.roundToLong(double, RoundingMode)")
   public void testRoundFractionalDoubleToLong() {
     for (double d : FRACTIONAL_DOUBLE_CANDIDATES) {
       for (RoundingMode mode : ALL_SAFE_ROUNDING_MODES) {
         BigDecimal expected = new BigDecimal(d).setScale(0, mode);
         boolean isInBounds = expected.compareTo(MAX_LONG_AS_BIG_DECIMAL) <= 0
             & expected.compareTo(MIN_LONG_AS_BIG_DECIMAL) >= 0;
 
         try {
           assertEquals(expected.longValue(), DoubleMath.roundToLong(d, mode));
           assertTrue(isInBounds);
         } catch (ArithmeticException e) {
           assertFalse(isInBounds);
         }
       }
     }
   }
 
   @GwtIncompatible("DoubleMath.roundToLong(double, RoundingMode)")
   public void testRoundExactIntegralDoubleToLong() {
     for (double d : INTEGRAL_DOUBLE_CANDIDATES) {
       // every mode except UNNECESSARY
       BigDecimal expected = new BigDecimal(d).setScale(0, UNNECESSARY);
       boolean isInBounds = expected.compareTo(MAX_LONG_AS_BIG_DECIMAL) <= 0
           & expected.compareTo(MIN_LONG_AS_BIG_DECIMAL) >= 0;
 
       try {
         assertEquals(expected.longValue(), DoubleMath.roundToLong(d, UNNECESSARY));
         assertTrue(isInBounds);
       } catch (ArithmeticException e) {
         assertFalse(isInBounds);
       }
     }
   }
 
   @GwtIncompatible("DoubleMath.roundToLong(double, RoundingMode)")
   public void testRoundExactFractionalDoubleToLongFails() {
     for (double d : FRACTIONAL_DOUBLE_CANDIDATES) {
       try {
         DoubleMath.roundToLong(d, UNNECESSARY);
         fail("Expected ArithmeticException");
       } catch (ArithmeticException expected) {}
     }
   }
 
   @GwtIncompatible("DoubleMath.roundToLong(double, RoundingMode)")
   public void testRoundNaNToLongAlwaysFails() {
     for (RoundingMode mode : ALL_ROUNDING_MODES) {
       try {
         DoubleMath.roundToLong(Double.NaN, mode);
         fail("Expected ArithmeticException");
       } catch (ArithmeticException expected) {}
     }
   }
 
   @GwtIncompatible("DoubleMath.roundToLong(double, RoundingMode)")
   public void testRoundInfiniteToLongAlwaysFails() {
     for (RoundingMode mode : ALL_ROUNDING_MODES) {
       try {
         DoubleMath.roundToLong(Double.POSITIVE_INFINITY, mode);
         fail("Expected ArithmeticException");
       } catch (ArithmeticException expected) {}
       try {
         DoubleMath.roundToLong(Double.NEGATIVE_INFINITY, mode);
         fail("Expected ArithmeticException");
       } catch (ArithmeticException expected) {}
     }
   }
 
   @GwtIncompatible("DoubleMath.roundToBigInteger(double, RoundingMode)")
   public void testRoundIntegralDoubleToBigInteger() {
     for (double d : INTEGRAL_DOUBLE_CANDIDATES) {
       for (RoundingMode mode : ALL_SAFE_ROUNDING_MODES) {
         BigDecimal expected = new BigDecimal(d).setScale(0, mode);
         assertEquals(expected.toBigInteger(), DoubleMath.roundToBigInteger(d, mode));
       }
     }
   }
 
   @GwtIncompatible("DoubleMath.roundToBigInteger(double, RoundingMode)")
   public void testRoundFractionalDoubleToBigInteger() {
     for (double d : FRACTIONAL_DOUBLE_CANDIDATES) {
       for (RoundingMode mode : ALL_SAFE_ROUNDING_MODES) {
         BigDecimal expected = new BigDecimal(d).setScale(0, mode);
         assertEquals(expected.toBigInteger(), DoubleMath.roundToBigInteger(d, mode));
       }
     }
   }
 
   @GwtIncompatible("DoubleMath.roundToBigInteger(double, RoundingMode)")
   public void testRoundExactIntegralDoubleToBigInteger() {
     for (double d : INTEGRAL_DOUBLE_CANDIDATES) {
       BigDecimal expected = new BigDecimal(d).setScale(0, UNNECESSARY);
       assertEquals(expected.toBigInteger(), DoubleMath.roundToBigInteger(d, UNNECESSARY));
     }
   }
 
   @GwtIncompatible("DoubleMath.roundToBigInteger(double, RoundingMode)")
   public void testRoundExactFractionalDoubleToBigIntegerFails() {
     for (double d : FRACTIONAL_DOUBLE_CANDIDATES) {
       try {
         DoubleMath.roundToBigInteger(d, UNNECESSARY);
         fail("Expected ArithmeticException");
       } catch (ArithmeticException expected) {}
     }
   }
 
   @GwtIncompatible("DoubleMath.roundToBigInteger(double, RoundingMode)")
   public void testRoundNaNToBigIntegerAlwaysFails() {
     for (RoundingMode mode : ALL_ROUNDING_MODES) {
       try {
         DoubleMath.roundToBigInteger(Double.NaN, mode);
         fail("Expected ArithmeticException");
       } catch (ArithmeticException expected) {}
     }
   }
 
   @GwtIncompatible("DoubleMath.roundToBigInteger(double, RoundingMode)")
   public void testRoundInfiniteToBigIntegerAlwaysFails() {
     for (RoundingMode mode : ALL_ROUNDING_MODES) {
       try {
         DoubleMath.roundToBigInteger(Double.POSITIVE_INFINITY, mode);
         fail("Expected ArithmeticException");
       } catch (ArithmeticException expected) {}
       try {
         DoubleMath.roundToBigInteger(Double.NEGATIVE_INFINITY, mode);
         fail("Expected ArithmeticException");
       } catch (ArithmeticException expected) {}
     }
   }
 
   @GwtIncompatible("DoubleMath.roundToBigInteger(double, RoundingMode)")
   public void testRoundLog2Floor() {
     for (double d : POSITIVE_FINITE_DOUBLE_CANDIDATES) {
       int log2 = DoubleMath.log2(d, FLOOR);
       assertTrue(StrictMath.pow(2.0, log2) <= d);
       assertTrue(StrictMath.pow(2.0, log2 + 1) > d);
     }
   }
 
   @GwtIncompatible("DoubleMath.log2(double, RoundingMode), StrictMath")
   public void testRoundLog2Ceiling() {
     for (double d : POSITIVE_FINITE_DOUBLE_CANDIDATES) {
       int log2 = DoubleMath.log2(d, CEILING);
       assertTrue(StrictMath.pow(2.0, log2) >= d);
       double z = StrictMath.pow(2.0, log2 - 1);
       assertTrue(z < d);
     }
   }
 
   @GwtIncompatible("DoubleMath.log2(double, RoundingMode), StrictMath")
   public void testRoundLog2Down() {
     for (double d : POSITIVE_FINITE_DOUBLE_CANDIDATES) {
       int log2 = DoubleMath.log2(d, DOWN);
       if (d >= 1.0) {
         assertTrue(log2 >= 0);
         assertTrue(StrictMath.pow(2.0, log2) <= d);
         assertTrue(StrictMath.pow(2.0, log2 + 1) > d);
       } else {
         assertTrue(log2 <= 0);
         assertTrue(StrictMath.pow(2.0, log2) >= d);
         assertTrue(StrictMath.pow(2.0, log2 - 1) < d);
       }
     }
   }
 
   @GwtIncompatible("DoubleMath.log2(double, RoundingMode), StrictMath")
   public void testRoundLog2Up() {
     for (double d : POSITIVE_FINITE_DOUBLE_CANDIDATES) {
       int log2 = DoubleMath.log2(d, UP);
       if (d >= 1.0) {
         assertTrue(log2 >= 0);
         assertTrue(StrictMath.pow(2.0, log2) >= d);
         assertTrue(StrictMath.pow(2.0, log2 - 1) < d);
       } else {
         assertTrue(log2 <= 0);
         assertTrue(StrictMath.pow(2.0, log2) <= d);
         assertTrue(StrictMath.pow(2.0, log2 + 1) > d);
       }
     }
   }
 
   @GwtIncompatible("DoubleMath.log2(double, RoundingMode)")
   public void testRoundLog2Half() {
     // We don't expect perfect rounding accuracy.
     for (int exp : asList(-1022, -50, -1, 0, 1, 2, 3, 4, 100, 1022, 1023)) {
       for (RoundingMode mode : asList(HALF_EVEN, HALF_UP, HALF_DOWN)) {
         double x = Math.scalb(Math.sqrt(2) + 0.001, exp);
         double y = Math.scalb(Math.sqrt(2) - 0.001, exp);
         if (exp < 0) {
           assertEquals(exp + 1, DoubleMath.log2(x, mode));
           assertEquals(exp, DoubleMath.log2(y, mode));
         } else {
           assertEquals(exp + 1, DoubleMath.log2(x, mode));
           assertEquals(exp, DoubleMath.log2(y, mode));
         }
       }
     }
   }
 
   @GwtIncompatible("DoubleMath.log2(double, RoundingMode)")
   public void testRoundLog2Exact() {
     for (double x : POSITIVE_FINITE_DOUBLE_CANDIDATES) {
       boolean isPowerOfTwo = StrictMath.pow(2.0, DoubleMath.log2(x, FLOOR)) == x;
       try {
         int log2 = DoubleMath.log2(x, UNNECESSARY);
         assertEquals(x, Math.scalb(1.0, log2));
         assertTrue(isPowerOfTwo);
       } catch (ArithmeticException e) {
         assertFalse(isPowerOfTwo);
       }
     }
   }
 
   @GwtIncompatible("DoubleMath.log2(double, RoundingMode)")
   public void testRoundLog2ThrowsOnZerosInfinitiesAndNaN() {
     for (RoundingMode mode : ALL_ROUNDING_MODES) {
       for (double d :
           asList(0.0, -0.0, Double.POSITIVE_INFINITY, Double.NEGATIVE_INFINITY, Double.NaN)) {
         try {
           DoubleMath.log2(d, mode);
           fail("Expected IllegalArgumentException");
         } catch (IllegalArgumentException expected) {}
       }
     }
   }
 
   @GwtIncompatible("DoubleMath.log2(double, RoundingMode)")
   public void testRoundLog2ThrowsOnNegative() {
     for (RoundingMode mode : ALL_ROUNDING_MODES) {
       for (double d : POSITIVE_FINITE_DOUBLE_CANDIDATES) {
         try {
           DoubleMath.log2(-d, mode);
           fail("Expected IllegalArgumentException");
         } catch (IllegalArgumentException expected) {}
       }
     }
   }
 
   @GwtIncompatible("DoubleMath.isPowerOfTwo, DoubleMath.log2(double, RoundingMode), StrictMath")
   public void testIsPowerOfTwoYes() {
     for (int i = -1074; i <= 1023; i++) {
       assertTrue(DoubleMath.isPowerOfTwo(StrictMath.pow(2.0, i)));
     }
   }
 
   @GwtIncompatible("DoubleMath.isPowerOfTwo, DoubleMath.log2(double, RoundingMode), StrictMath")
   public void testIsPowerOfTwo() {
     for (double x : ALL_DOUBLE_CANDIDATES) {
       boolean expected = x > 0 && !Double.isInfinite(x) && !Double.isNaN(x)
           && StrictMath.pow(2.0, DoubleMath.log2(x, FLOOR)) == x;
       assertEquals(expected, DoubleMath.isPowerOfTwo(x));
     }
   }
 
   @GwtIncompatible("#trueLog2, Math.ulp")
   public void testLog2Accuracy() {
     for (double d : POSITIVE_FINITE_DOUBLE_CANDIDATES) {
       double dmLog2 = DoubleMath.log2(d);
       double trueLog2 = trueLog2(d);
       assertTrue(Math.abs(dmLog2 - trueLog2) <= Math.ulp(trueLog2));
     }
   }
 
   public void testLog2SemiMonotonic() {
     for (double d : POSITIVE_FINITE_DOUBLE_CANDIDATES) {
       assertTrue(DoubleMath.log2(d + 0.01) >= DoubleMath.log2(d));
     }
   }
 
   public void testLog2Negative() {
     for (double d : POSITIVE_FINITE_DOUBLE_CANDIDATES) {
       assertTrue(Double.isNaN(DoubleMath.log2(-d)));
     }
   }
 
   public void testLog2Zero() {
     assertEquals(Double.NEGATIVE_INFINITY, DoubleMath.log2(0.0));
     assertEquals(Double.NEGATIVE_INFINITY, DoubleMath.log2(-0.0));
   }
 
   public void testLog2NaNInfinity() {
     assertEquals(Double.POSITIVE_INFINITY, DoubleMath.log2(Double.POSITIVE_INFINITY));
     assertTrue(Double.isNaN(DoubleMath.log2(Double.NEGATIVE_INFINITY)));
     assertTrue(Double.isNaN(DoubleMath.log2(Double.NaN)));
   }
 
   @GwtIncompatible("StrictMath")
   private strictfp double trueLog2(double d) {
     double trueLog2 = StrictMath.log(d) / StrictMath.log(2);
     // increment until it's >= the true value
     while (StrictMath.pow(2.0, trueLog2) < d) {
       trueLog2 = StrictMath.nextUp(trueLog2);
     }
     // decrement until it's <= the true value
     while (StrictMath.pow(2.0, trueLog2) > d) {
       trueLog2 = StrictMath.nextAfter(trueLog2, Double.NEGATIVE_INFINITY);
     }
     if (StrictMath.abs(StrictMath.pow(2.0, trueLog2) - d)
         > StrictMath.abs(StrictMath.pow(2.0, StrictMath.nextUp(trueLog2)) - d)) {
       trueLog2 = StrictMath.nextUp(trueLog2);
     }
     return trueLog2;
   }
 
   @GwtIncompatible("DoubleMath.isMathematicalInteger")
   public void testIsMathematicalIntegerIntegral() {
     for (double d : INTEGRAL_DOUBLE_CANDIDATES) {
       assertTrue(DoubleMath.isMathematicalInteger(d));
     }
   }
 
   @GwtIncompatible("DoubleMath.isMathematicalInteger")
   public void testIsMathematicalIntegerFractional() {
     for (double d : FRACTIONAL_DOUBLE_CANDIDATES) {
       assertFalse(DoubleMath.isMathematicalInteger(d));
     }
   }
 
   @GwtIncompatible("DoubleMath.isMathematicalInteger")
   public void testIsMathematicalIntegerNotFinite() {
     for (double d :
         Arrays.asList(Double.POSITIVE_INFINITY, Double.NEGATIVE_INFINITY, Double.NaN)) {
       assertFalse(DoubleMath.isMathematicalInteger(d));
     }
   }
 
   @GwtIncompatible("Math.ulp")
   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 testFactorialTooHigh() {
     assertEquals(Double.POSITIVE_INFINITY, DoubleMath.factorial(DoubleMath.MAX_FACTORIAL + 1));
     assertEquals(Double.POSITIVE_INFINITY, DoubleMath.factorial(DoubleMath.MAX_FACTORIAL + 20));
   }
 
   public void testFactorialNegative() {
     for (int n : NEGATIVE_INTEGER_CANDIDATES) {
       try {
         DoubleMath.factorial(n);
         fail("Expected IllegalArgumentException");
       } catch (IllegalArgumentException expected) {}
     }
   }
 
   private static final ImmutableList<Double> FINITE_TOLERANCE_CANDIDATES =
       ImmutableList.of(-0.0, 0.0, 1.0, 100.0, 10000.0, Double.MAX_VALUE);
 
   private static final Iterable<Double> TOLERANCE_CANDIDATES =
       Iterables.concat(FINITE_TOLERANCE_CANDIDATES, ImmutableList.of(Double.POSITIVE_INFINITY));
 
   private static final List<Double> BAD_TOLERANCE_CANDIDATES =
       Doubles.asList(-Double.MIN_VALUE, -Double.MIN_NORMAL, -1, -20, Double.NaN,
           Double.NEGATIVE_INFINITY, -0.001);
 
   public void testFuzzyEqualsFinite() {
     for (double a : FINITE_DOUBLE_CANDIDATES) {
       for (double b : FINITE_DOUBLE_CANDIDATES) {
         for (double tolerance : FINITE_TOLERANCE_CANDIDATES) {
           assertEquals(
               Math.abs(a - b) <= tolerance,
               DoubleMath.fuzzyEquals(a, b, tolerance));
         }
       }
     }
   }
 
   public void testFuzzyInfiniteVersusFiniteWithFiniteTolerance() {
     for (double inf : INFINITIES) {
       for (double a : FINITE_DOUBLE_CANDIDATES) {
         for (double tolerance : FINITE_TOLERANCE_CANDIDATES) {
           assertFalse(DoubleMath.fuzzyEquals(a, inf, tolerance));
           assertFalse(DoubleMath.fuzzyEquals(inf, a, tolerance));
         }
       }
     }
   }
 
   public void testFuzzyInfiniteVersusInfiniteWithFiniteTolerance() {
     for (double inf : INFINITIES) {
       for (double tolerance : FINITE_TOLERANCE_CANDIDATES) {
         assertTrue(DoubleMath.fuzzyEquals(inf, inf, tolerance));
         assertFalse(DoubleMath.fuzzyEquals(inf, -inf, tolerance));
       }
     }
   }
 
   public void testFuzzyEqualsInfiniteTolerance() {
     for (double a : DOUBLE_CANDIDATES_EXCEPT_NAN) {
       for (double b : DOUBLE_CANDIDATES_EXCEPT_NAN) {
         assertTrue(DoubleMath.fuzzyEquals(a, b, Double.POSITIVE_INFINITY));
       }
     }
   }
 
   public void testFuzzyEqualsOneNaN() {
     for (double a : DOUBLE_CANDIDATES_EXCEPT_NAN) {
       for (double tolerance : TOLERANCE_CANDIDATES) {
         assertFalse(DoubleMath.fuzzyEquals(a, Double.NaN, tolerance));
         assertFalse(DoubleMath.fuzzyEquals(Double.NaN, a, tolerance));
       }
     }
   }
 
   public void testFuzzyEqualsTwoNaNs() {
     for (double tolerance : TOLERANCE_CANDIDATES) {
       assertTrue(DoubleMath.fuzzyEquals(Double.NaN, Double.NaN, tolerance));
     }
   }
 
   public void testFuzzyEqualsZeroTolerance() {
     // make sure we test -0 tolerance
     for (double zero : Doubles.asList(0.0, -0.0)) {
       for (double a : ALL_DOUBLE_CANDIDATES) {
         for (double b : ALL_DOUBLE_CANDIDATES) {
           assertEquals(a == b || (Double.isNaN(a) && Double.isNaN(b)),
               DoubleMath.fuzzyEquals(a, b, zero));
         }
       }
     }
   }
 
   public void testFuzzyEqualsBadTolerance() {
     for (double tolerance : BAD_TOLERANCE_CANDIDATES) {
       try {
         DoubleMath.fuzzyEquals(1, 2, tolerance);
         fail("Expected IllegalArgumentException");
       } catch (IllegalArgumentException expected) {
         // success
       }
     }
   }
 
   public void testFuzzyCompare() {
     for (double a : ALL_DOUBLE_CANDIDATES) {
       for (double b : ALL_DOUBLE_CANDIDATES) {
         for (double tolerance : TOLERANCE_CANDIDATES) {
           int expected = DoubleMath.fuzzyEquals(a, b, tolerance) ? 0 : Double.compare(a, b);
           int actual = DoubleMath.fuzzyCompare(a, b, tolerance);
           assertEquals(Integer.signum(expected), Integer.signum(actual));
         }
       }
     }
   }
 
   public void testFuzzyCompareBadTolerance() {
     for (double tolerance : BAD_TOLERANCE_CANDIDATES) {
       try {
         DoubleMath.fuzzyCompare(1, 2, tolerance);
         fail("Expected IllegalArgumentException");
       } catch (IllegalArgumentException expected) {
         // success
       }
     }
   }
 
   @GwtIncompatible("DoubleMath.mean")
   public void testMean_doubleVarargs() {
     assertEquals(-1.375, DoubleMath.mean(1.1, -2.2, 4.4, -8.8), 1.0e-10);
     assertEquals(1.1, DoubleMath.mean(1.1), 1.0e-10);
     try {
       DoubleMath.mean(Double.NaN);
       fail("Expected IllegalArgumentException");
     } catch (IllegalArgumentException expected) {
     }
     try {
       DoubleMath.mean(Double.POSITIVE_INFINITY);
       fail("Expected IllegalArgumentException");
     } catch (IllegalArgumentException expected) {
     }
   }
 
   @GwtIncompatible("DoubleMath.mean")
   public void testMean_intVarargs() {
     assertEquals(-13.75, DoubleMath.mean(11, -22, 44, -88), 1.0e-10);
     assertEquals(11.0, DoubleMath.mean(11), 1.0e-10);
   }
 
   @GwtIncompatible("DoubleMath.mean")
   public void testMean_longVarargs() {
     assertEquals(-13.75, DoubleMath.mean(11L, -22L, 44L, -88L), 1.0e-10);
     assertEquals(11.0, DoubleMath.mean(11L), 1.0e-10);
   }
 
   @GwtIncompatible("DoubleMath.mean")
   public void testMean_emptyVarargs() {
     try {
       DoubleMath.mean();
       fail("Expected IllegalArgumentException");
     } catch (IllegalArgumentException expected) {
     }
   }
 
   @GwtIncompatible("DoubleMath.mean")
   public void testMean_doubleIterable() {
     assertEquals(-1.375, DoubleMath.mean(ImmutableList.of(1.1, -2.2, 4.4, -8.8)), 1.0e-10);
     assertEquals(1.1, DoubleMath.mean(ImmutableList.of(1.1)), 1.0e-10);
     try {
       DoubleMath.mean(ImmutableList.<Double>of());
       fail("Expected IllegalArgumentException");
     } catch (IllegalArgumentException expected) {
     }
     try {
       DoubleMath.mean(ImmutableList.of(Double.NaN));
       fail("Expected IllegalArgumentException");
     } catch (IllegalArgumentException expected) {
     }
     try {
       DoubleMath.mean(ImmutableList.of(Double.POSITIVE_INFINITY));
       fail("Expected IllegalArgumentException");
     } catch (IllegalArgumentException expected) {
     }
   }
 
   @GwtIncompatible("DoubleMath.mean")
   public void testMean_intIterable() {
     assertEquals(-13.75, DoubleMath.mean(ImmutableList.of(11, -22, 44, -88)), 1.0e-10);
     assertEquals(11, DoubleMath.mean(ImmutableList.of(11)), 1.0e-10);
     try {
       DoubleMath.mean(ImmutableList.<Integer>of());
       fail("Expected IllegalArgumentException");
     } catch (IllegalArgumentException expected) {
     }
   }
 
   @GwtIncompatible("DoubleMath.mean")
   public void testMean_longIterable() {
     assertEquals(-13.75, DoubleMath.mean(ImmutableList.of(11L, -22L, 44L, -88L)), 1.0e-10);
     assertEquals(11, DoubleMath.mean(ImmutableList.of(11L)), 1.0e-10);
     try {
       DoubleMath.mean(ImmutableList.<Long>of());
       fail("Expected IllegalArgumentException");
     } catch (IllegalArgumentException expected) {
     }
   }
 
   @GwtIncompatible("DoubleMath.mean")
   public void testMean_intIterator() {
     assertEquals(-13.75, DoubleMath.mean(ImmutableList.of(11, -22, 44, -88).iterator()), 1.0e-10);
     assertEquals(11, DoubleMath.mean(ImmutableList.of(11).iterator()), 1.0e-10);
     try {
       DoubleMath.mean(ImmutableList.<Integer>of().iterator());
       fail("Expected IllegalArgumentException");
     } catch (IllegalArgumentException expected) {
     }
   }
 
   @GwtIncompatible("DoubleMath.mean")
   public void testMean_longIterator() {
     assertEquals(-13.75, DoubleMath.mean(ImmutableList.of(11L, -22L, 44L, -88L).iterator()),
         1.0e-10);
     assertEquals(11, DoubleMath.mean(ImmutableList.of(11L).iterator()), 1.0e-10);
     try {
       DoubleMath.mean(ImmutableList.<Long>of().iterator());
       fail("Expected IllegalArgumentException");
     } catch (IllegalArgumentException expected) {
     }
   }
 
   @GwtIncompatible("NullPointerTester")
   public void testNullPointers() {
     NullPointerTester tester = new NullPointerTester();
     tester.setDefault(double.class, 3.0);
     tester.testAllPublicStaticMethods(DoubleMath.class);
   }
 }