Java example source code file (PredicatesTest.java)

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Java - Java tags/keywords

collection, equalstester, exception, false, gwtincompatible, integer, never_reached, nullpointertester, override, predicate, regex, serializabletester, string, suppresswarnings, true, util

The PredicatesTest.java Java example source code

/*
 * Copyright (C) 2005 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.base;

import static com.google.common.base.CharMatcher.whitespace;
import static com.google.common.collect.Lists.newArrayList;

import com.google.common.annotations.GwtCompatible;
import com.google.common.annotations.GwtIncompatible;
import com.google.common.collect.ImmutableSet;
import com.google.common.testing.ClassSanityTester;
import com.google.common.testing.EqualsTester;
import com.google.common.testing.NullPointerTester;
import com.google.common.testing.SerializableTester;

import junit.framework.AssertionFailedError;
import junit.framework.TestCase;

import java.io.Serializable;
import java.util.ArrayList;
import java.util.Arrays;
import java.util.Collection;
import java.util.Collections;
import java.util.Iterator;
import java.util.List;
import java.util.regex.Pattern;

/**
 * Unit test for {@link Predicates}.
 *
 * @author Kevin Bourrillion
 */
@GwtCompatible(emulated = true)
public class PredicatesTest extends TestCase {
  private static final Predicate<Integer> TRUE = Predicates.alwaysTrue();
  private static final Predicate<Integer> FALSE = Predicates.alwaysFalse();
  private static final Predicate<Integer> NEVER_REACHED =
      new Predicate<Integer>() {
    @Override
    public boolean apply(Integer i) {
      throw new AssertionFailedError(
          "This predicate should never have been evaluated");
    }
  };

  /** Instantiable predicate with reasonable hashCode() and equals() methods. */
  static class IsOdd implements Predicate<Integer>, Serializable {
    private static final long serialVersionUID = 0x150ddL;
    @Override
    public boolean apply(Integer i) {
      return (i.intValue() & 1) == 1;
    }
    @Override public int hashCode() {
      return 0x150dd;
    }
    @Override public boolean equals(Object obj) {
      return obj instanceof IsOdd;
    }
    @Override public String toString() {
      return "IsOdd";
    }
  }

  /**
   * Generates a new Predicate per call.
   *
   * <p>Creating a new Predicate each time helps catch cases where code is
   * using {@code x == y} instead of {@code x.equals(y)}.
   */
  private static IsOdd isOdd() {
    return new IsOdd();
  }

  /*
   * Tests for Predicates.alwaysTrue().
   */

  public void testAlwaysTrue_apply() {
    assertEvalsToTrue(Predicates.alwaysTrue());
  }

  public void testAlwaysTrue_equality() throws Exception {
    new EqualsTester()
        .addEqualityGroup(TRUE, Predicates.alwaysTrue())
        .addEqualityGroup(isOdd())
        .addEqualityGroup(Predicates.alwaysFalse())
        .testEquals();
  }

  @GwtIncompatible // SerializableTester
  public void testAlwaysTrue_serialization() {
    checkSerialization(Predicates.alwaysTrue());
  }

  /*
   * Tests for Predicates.alwaysFalse().
   */

  public void testAlwaysFalse_apply() throws Exception {
    assertEvalsToFalse(Predicates.alwaysFalse());
  }

  public void testAlwaysFalse_equality() throws Exception {
    new EqualsTester()
        .addEqualityGroup(FALSE, Predicates.alwaysFalse())
        .addEqualityGroup(isOdd())
        .addEqualityGroup(Predicates.alwaysTrue())
        .testEquals();
  }

  @GwtIncompatible // SerializableTester
  public void testAlwaysFalse_serialization() {
    checkSerialization(Predicates.alwaysFalse());
  }

  /*
   * Tests for Predicates.not(predicate).
   */

  public void testNot_apply() {
    assertEvalsToTrue(Predicates.not(FALSE));
    assertEvalsToFalse(Predicates.not(TRUE));
    assertEvalsLikeOdd(Predicates.not(Predicates.not(isOdd())));
  }

  public void testNot_equality() {
    new EqualsTester()
        .addEqualityGroup(Predicates.not(isOdd()), Predicates.not(isOdd()))
        .addEqualityGroup(Predicates.not(TRUE))
        .addEqualityGroup(isOdd())
        .testEquals();
  }

  public void testNot_equalityForNotOfKnownValues() {
    new EqualsTester()
        .addEqualityGroup(TRUE, Predicates.alwaysTrue())
        .addEqualityGroup(FALSE)
        .addEqualityGroup(Predicates.not(TRUE))
        .testEquals();

    new EqualsTester()
        .addEqualityGroup(FALSE, Predicates.alwaysFalse())
        .addEqualityGroup(TRUE)
        .addEqualityGroup(Predicates.not(FALSE))
        .testEquals();

    new EqualsTester()
        .addEqualityGroup(Predicates.isNull(), Predicates.isNull())
        .addEqualityGroup(Predicates.notNull())
        .addEqualityGroup(Predicates.not(Predicates.isNull()))
        .testEquals();

    new EqualsTester()
        .addEqualityGroup(Predicates.notNull(), Predicates.notNull())
        .addEqualityGroup(Predicates.isNull())
        .addEqualityGroup(Predicates.not(Predicates.notNull()))
        .testEquals();
  }

  @GwtIncompatible // SerializableTester
  public void testNot_serialization() {
    checkSerialization(Predicates.not(isOdd()));
  }

  /*
   * Tests for all the different flavors of Predicates.and().
   */

  @SuppressWarnings("unchecked") // varargs
  public void testAnd_applyNoArgs() {
    assertEvalsToTrue(Predicates.and());
  }

  @SuppressWarnings("unchecked") // varargs
  public void testAnd_equalityNoArgs() {
    new EqualsTester()
        .addEqualityGroup(Predicates.and(), Predicates.and())
        .addEqualityGroup(Predicates.and(FALSE))
        .addEqualityGroup(Predicates.or())
        .testEquals();
  }

  @GwtIncompatible // SerializableTester
  @SuppressWarnings("unchecked") // varargs
  public void testAnd_serializationNoArgs() {
    checkSerialization(Predicates.and());
  }

  @SuppressWarnings("unchecked") // varargs
  public void testAnd_applyOneArg() {
    assertEvalsLikeOdd(Predicates.and(isOdd()));
  }

  @SuppressWarnings("unchecked") // varargs
  public void testAnd_equalityOneArg() {
    Object[] notEqualObjects = {Predicates.and(NEVER_REACHED, FALSE)};
    new EqualsTester()
        .addEqualityGroup(
            Predicates.and(NEVER_REACHED), Predicates.and(NEVER_REACHED))
        .addEqualityGroup(notEqualObjects)
        .addEqualityGroup(Predicates.and(isOdd()))
        .addEqualityGroup(Predicates.and())
        .addEqualityGroup(Predicates.or(NEVER_REACHED))
        .testEquals();
  }

  @GwtIncompatible // SerializableTester
  @SuppressWarnings("unchecked") // varargs
  public void testAnd_serializationOneArg() {
    checkSerialization(Predicates.and(isOdd()));
  }

  public void testAnd_applyBinary() {
    assertEvalsLikeOdd(Predicates.and(isOdd(), TRUE));
    assertEvalsLikeOdd(Predicates.and(TRUE, isOdd()));
    assertEvalsToFalse(Predicates.and(FALSE, NEVER_REACHED));
  }

  @SuppressWarnings("unchecked") // varargs
  public void testAnd_equalityBinary() {
    new EqualsTester()
        .addEqualityGroup(
            Predicates.and(TRUE, NEVER_REACHED),
            Predicates.and(TRUE, NEVER_REACHED))
        .addEqualityGroup(Predicates.and(NEVER_REACHED, TRUE))
        .addEqualityGroup(Predicates.and(TRUE))
        .addEqualityGroup(Predicates.or(TRUE, NEVER_REACHED))
        .testEquals();
  }

  @GwtIncompatible // SerializableTester
  public void testAnd_serializationBinary() {
    checkSerialization(Predicates.and(TRUE, isOdd()));
  }

  @SuppressWarnings("unchecked") // varargs
  public void testAnd_applyTernary() {
    assertEvalsLikeOdd(Predicates.and(isOdd(), TRUE, TRUE));
    assertEvalsLikeOdd(Predicates.and(TRUE, isOdd(), TRUE));
    assertEvalsLikeOdd(Predicates.and(TRUE, TRUE, isOdd()));
    assertEvalsToFalse(Predicates.and(TRUE, FALSE, NEVER_REACHED));
  }

  @SuppressWarnings("unchecked") // varargs
  public void testAnd_equalityTernary() {
    new EqualsTester()
        .addEqualityGroup(
            Predicates.and(TRUE, isOdd(), NEVER_REACHED),
            Predicates.and(TRUE, isOdd(), NEVER_REACHED))
        .addEqualityGroup(Predicates.and(isOdd(), NEVER_REACHED, TRUE))
        .addEqualityGroup(Predicates.and(TRUE))
        .addEqualityGroup(Predicates.or(TRUE, isOdd(), NEVER_REACHED))
        .testEquals();
  }

  @GwtIncompatible // SerializableTester
  @SuppressWarnings("unchecked") // varargs
  public void testAnd_serializationTernary() {
    checkSerialization(Predicates.and(TRUE, isOdd(), FALSE));
  }

  @SuppressWarnings("unchecked") // varargs
  public void testAnd_applyIterable() {
    Collection<Predicate empty = Arrays.asList();
    assertEvalsToTrue(Predicates.and(empty));
    assertEvalsLikeOdd(Predicates.and(Arrays.asList(isOdd())));
    assertEvalsLikeOdd(Predicates.and(Arrays.asList(TRUE, isOdd())));
    assertEvalsToFalse(Predicates.and(Arrays.asList(FALSE, NEVER_REACHED)));
  }

  @SuppressWarnings("unchecked") // varargs
  public void testAnd_equalityIterable() {
    new EqualsTester()
        .addEqualityGroup(
            Predicates.and(Arrays.asList(TRUE, NEVER_REACHED)),
            Predicates.and(Arrays.asList(TRUE, NEVER_REACHED)),
            Predicates.and(TRUE, NEVER_REACHED))
        .addEqualityGroup(Predicates.and(FALSE, NEVER_REACHED))
        .addEqualityGroup(Predicates.or(TRUE, NEVER_REACHED))
        .testEquals();
  }

  @GwtIncompatible // SerializableTester
  @SuppressWarnings("unchecked") // varargs
  public void testAnd_serializationIterable() {
    checkSerialization(Predicates.and(Arrays.asList(TRUE, FALSE)));
  }

  @SuppressWarnings("unchecked") // varargs
  public void testAnd_arrayDefensivelyCopied() {
    Predicate[] array = {Predicates.alwaysFalse()};
    Predicate<Object> predicate = Predicates.and(array);
    assertFalse(predicate.apply(1));
    array[0] = Predicates.alwaysTrue();
    assertFalse(predicate.apply(1));
  }

  public void testAnd_listDefensivelyCopied() {
    List<Predicate list = newArrayList();
    Predicate<Object> predicate = Predicates.and(list);
    assertTrue(predicate.apply(1));
    list.add(Predicates.alwaysFalse());
    assertTrue(predicate.apply(1));
  }

  public void testAnd_iterableDefensivelyCopied() {
    final List<Predicate list = newArrayList();
    Iterable<Predicate iterable = new Iterable>() {
      @Override
      public Iterator<Predicate iterator() {
        return list.iterator();
      }
    };
    Predicate<Object> predicate = Predicates.and(iterable);
    assertTrue(predicate.apply(1));
    list.add(Predicates.alwaysFalse());
    assertTrue(predicate.apply(1));
  }

  /*
   * Tests for all the different flavors of Predicates.or().
   */

  @SuppressWarnings("unchecked") // varargs
  public void testOr_applyNoArgs() {
    assertEvalsToFalse(Predicates.or());
  }

  @SuppressWarnings("unchecked") // varargs
  public void testOr_equalityNoArgs() {
    new EqualsTester()
        .addEqualityGroup(Predicates.or(), Predicates.or())
        .addEqualityGroup(Predicates.or(TRUE))
        .addEqualityGroup(Predicates.and())
        .testEquals();
  }

  @GwtIncompatible // SerializableTester
  @SuppressWarnings("unchecked") // varargs
  public void testOr_serializationNoArgs() {
    checkSerialization(Predicates.or());
  }

  @SuppressWarnings("unchecked") // varargs
  public void testOr_applyOneArg() {
    assertEvalsToTrue(Predicates.or(TRUE));
    assertEvalsToFalse(Predicates.or(FALSE));
  }

  @SuppressWarnings("unchecked") // varargs
  public void testOr_equalityOneArg() {
    new EqualsTester()
        .addEqualityGroup(
            Predicates.or(NEVER_REACHED), Predicates.or(NEVER_REACHED))
        .addEqualityGroup(Predicates.or(NEVER_REACHED, TRUE))
        .addEqualityGroup(Predicates.or(TRUE))
        .addEqualityGroup(Predicates.or())
        .addEqualityGroup(Predicates.and(NEVER_REACHED))
        .testEquals();
  }

  @GwtIncompatible // SerializableTester
  @SuppressWarnings("unchecked") // varargs
  public void testOr_serializationOneArg() {
    checkSerialization(Predicates.or(isOdd()));
  }

  public void testOr_applyBinary() {
    Predicate<Integer> falseOrFalse = Predicates.or(FALSE, FALSE);
    Predicate<Integer> falseOrTrue = Predicates.or(FALSE, TRUE);
    Predicate<Integer> trueOrAnything = Predicates.or(TRUE, NEVER_REACHED);

    assertEvalsToFalse(falseOrFalse);
    assertEvalsToTrue(falseOrTrue);
    assertEvalsToTrue(trueOrAnything);
  }

  @SuppressWarnings("unchecked") // varargs
  public void testOr_equalityBinary() {
    new EqualsTester()
        .addEqualityGroup(
            Predicates.or(FALSE, NEVER_REACHED),
            Predicates.or(FALSE, NEVER_REACHED))
        .addEqualityGroup(Predicates.or(NEVER_REACHED, FALSE))
        .addEqualityGroup(Predicates.or(TRUE))
        .addEqualityGroup(Predicates.and(FALSE, NEVER_REACHED))
        .testEquals();
  }

  @GwtIncompatible // SerializableTester
  public void testOr_serializationBinary() {
    checkSerialization(Predicates.or(isOdd(), TRUE));
  }

  @SuppressWarnings("unchecked") // varargs
  public void testOr_applyTernary() {
    assertEvalsLikeOdd(Predicates.or(isOdd(), FALSE, FALSE));
    assertEvalsLikeOdd(Predicates.or(FALSE, isOdd(), FALSE));
    assertEvalsLikeOdd(Predicates.or(FALSE, FALSE, isOdd()));
    assertEvalsToTrue(Predicates.or(FALSE, TRUE, NEVER_REACHED));
  }

  @SuppressWarnings("unchecked") // varargs
  public void testOr_equalityTernary() {
    new EqualsTester()
        .addEqualityGroup(
            Predicates.or(FALSE, NEVER_REACHED, TRUE),
            Predicates.or(FALSE, NEVER_REACHED, TRUE))
        .addEqualityGroup(Predicates.or(TRUE, NEVER_REACHED, FALSE))
        .addEqualityGroup(Predicates.or(TRUE))
        .addEqualityGroup(Predicates.and(FALSE, NEVER_REACHED, TRUE))
        .testEquals();
  }

  @GwtIncompatible // SerializableTester
  @SuppressWarnings("unchecked") // varargs
  public void testOr_serializationTernary() {
    checkSerialization(Predicates.or(FALSE, isOdd(), TRUE));
  }

  @SuppressWarnings("unchecked") // varargs
  public void testOr_applyIterable() {
    Predicate<Integer> vacuouslyFalse =
        Predicates.or(Collections.<PredicateemptyList());
    Predicate<Integer> troo = Predicates.or(Collections.singletonList(TRUE));
    /*
     * newLinkedList() takes varargs. TRUE and FALSE are both instances of
     * Predicate<Integer>, so the call is safe.
     */
    Predicate<Integer> trueAndFalse = Predicates.or(Arrays.asList(TRUE, FALSE));

    assertEvalsToFalse(vacuouslyFalse);
    assertEvalsToTrue(troo);
    assertEvalsToTrue(trueAndFalse);
  }

  @SuppressWarnings("unchecked") // varargs
  public void testOr_equalityIterable() {
    new EqualsTester()
        .addEqualityGroup(
            Predicates.or(Arrays.asList(FALSE, NEVER_REACHED)),
            Predicates.or(Arrays.asList(FALSE, NEVER_REACHED)),
            Predicates.or(FALSE, NEVER_REACHED))
        .addEqualityGroup(Predicates.or(TRUE, NEVER_REACHED))
        .addEqualityGroup(Predicates.and(FALSE, NEVER_REACHED))
        .testEquals();
  }

  @GwtIncompatible // SerializableTester
  @SuppressWarnings("unchecked") // varargs
  public void testOr_serializationIterable() {
    Predicate<Integer> pre = Predicates.or(Arrays.asList(TRUE, FALSE));
    Predicate<Integer> post = SerializableTester.reserializeAndAssert(pre);
    assertEquals(pre.apply(0), post.apply(0));
  }

  @SuppressWarnings("unchecked") // varargs
  public void testOr_arrayDefensivelyCopied() {
    Predicate[] array = {Predicates.alwaysFalse()};
    Predicate<Object> predicate = Predicates.or(array);
    assertFalse(predicate.apply(1));
    array[0] = Predicates.alwaysTrue();
    assertFalse(predicate.apply(1));
  }

  public void testOr_listDefensivelyCopied() {
    List<Predicate list = newArrayList();
    Predicate<Object> predicate = Predicates.or(list);
    assertFalse(predicate.apply(1));
    list.add(Predicates.alwaysTrue());
    assertFalse(predicate.apply(1));
  }

  public void testOr_iterableDefensivelyCopied() {
    final List<Predicate list = newArrayList();
    Iterable<Predicate iterable = new Iterable>() {
      @Override
      public Iterator<Predicate iterator() {
        return list.iterator();
      }
    };
    Predicate<Object> predicate = Predicates.or(iterable);
    assertFalse(predicate.apply(1));
    list.add(Predicates.alwaysTrue());
    assertFalse(predicate.apply(1));
  }

  /*
   * Tests for Predicates.equalTo(x).
   */

  public void testIsEqualTo_apply() {
    Predicate<Integer> isOne = Predicates.equalTo(1);

    assertTrue(isOne.apply(1));
    assertFalse(isOne.apply(2));
    assertFalse(isOne.apply(null));
  }

  public void testIsEqualTo_equality() {
    new EqualsTester()
        .addEqualityGroup(Predicates.equalTo(1), Predicates.equalTo(1))
        .addEqualityGroup(Predicates.equalTo(2))
        .addEqualityGroup(Predicates.equalTo(null))
        .testEquals();
  }

  @GwtIncompatible // SerializableTester
  public void testIsEqualTo_serialization() {
    checkSerialization(Predicates.equalTo(1));
  }

  public void testIsEqualToNull_apply() {
    Predicate<Integer> isNull = Predicates.equalTo(null);
    assertTrue(isNull.apply(null));
    assertFalse(isNull.apply(1));
  }

  public void testIsEqualToNull_equality() {
    new EqualsTester()
        .addEqualityGroup(Predicates.equalTo(null), Predicates.equalTo(null))
        .addEqualityGroup(Predicates.equalTo(1))
        .addEqualityGroup(Predicates.equalTo("null"))
        .testEquals();
  }

  @GwtIncompatible // SerializableTester
  public void testIsEqualToNull_serialization() {
    checkSerialization(Predicates.equalTo(null));
  }

  /**
   * Tests for Predicates.instanceOf(x).
   * TODO: Fix the comment style after fixing annotation stripper to remove
   * comments properly.  Currently, all tests before the comments are removed
   * as well.
   */
  @GwtIncompatible // Predicates.instanceOf
  public void testIsInstanceOf_apply() {
    Predicate<Object> isInteger = Predicates.instanceOf(Integer.class);

    assertTrue(isInteger.apply(1));
    assertFalse(isInteger.apply(2.0f));
    assertFalse(isInteger.apply(""));
    assertFalse(isInteger.apply(null));
  }

  @GwtIncompatible // Predicates.instanceOf
  public void testIsInstanceOf_subclass() {
    Predicate<Object> isNumber = Predicates.instanceOf(Number.class);

    assertTrue(isNumber.apply(1));
    assertTrue(isNumber.apply(2.0f));
    assertFalse(isNumber.apply(""));
    assertFalse(isNumber.apply(null));
  }

  @GwtIncompatible // Predicates.instanceOf
  public void testIsInstanceOf_interface() {
    Predicate<Object> isComparable = Predicates.instanceOf(Comparable.class);

    assertTrue(isComparable.apply(1));
    assertTrue(isComparable.apply(2.0f));
    assertTrue(isComparable.apply(""));
    assertFalse(isComparable.apply(null));
  }

  @GwtIncompatible // Predicates.instanceOf
  public void testIsInstanceOf_equality() {
    new EqualsTester()
        .addEqualityGroup(
            Predicates.instanceOf(Integer.class),
            Predicates.instanceOf(Integer.class))
        .addEqualityGroup(Predicates.instanceOf(Number.class))
        .addEqualityGroup(Predicates.instanceOf(Float.class))
        .testEquals();
  }

  @GwtIncompatible // Predicates.instanceOf, SerializableTester
  public void testIsInstanceOf_serialization() {
    checkSerialization(Predicates.instanceOf(Integer.class));
  }

  @GwtIncompatible // Predicates.subtypeOf
  public void testSubtypeOf_apply() {
    Predicate<Class isInteger = Predicates.subtypeOf(Integer.class);

    assertTrue(isInteger.apply(Integer.class));
    assertFalse(isInteger.apply(Float.class));

    try {
      isInteger.apply(null);
      fail();
    } catch (NullPointerException expected) {}
  }

  @GwtIncompatible // Predicates.subtypeOf
  public void testSubtypeOf_subclass() {
    Predicate<Class isNumber = Predicates.subtypeOf(Number.class);

    assertTrue(isNumber.apply(Integer.class));
    assertTrue(isNumber.apply(Float.class));
  }

  @GwtIncompatible // Predicates.subtypeOf
  public void testSubtypeOf_interface() {
    Predicate<Class isComparable =
        Predicates.subtypeOf(Comparable.class);

    assertTrue(isComparable.apply(Integer.class));
    assertTrue(isComparable.apply(Float.class));
  }

  @GwtIncompatible // Predicates.subtypeOf
  @SuppressWarnings("deprecation")
  public void testSubtypeOf_equality() {
    new EqualsTester()
        .addEqualityGroup(
            Predicates.subtypeOf(Integer.class),
            Predicates.subtypeOf(Integer.class),
            Predicates.assignableFrom(Integer.class))
        .addEqualityGroup(Predicates.subtypeOf(Number.class))
        .addEqualityGroup(Predicates.subtypeOf(Float.class))
        .testEquals();
  }

  @GwtIncompatible // Predicates.subtypeOf, SerializableTester
  public void testSubtypeOf_serialization() {
    Predicate<Class predicate =
        Predicates.subtypeOf(Integer.class);
    Predicate<Class reserialized =
        SerializableTester.reserializeAndAssert(predicate);

    assertEvalsLike(predicate, reserialized, Integer.class);
    assertEvalsLike(predicate, reserialized, Float.class);
    assertEvalsLike(predicate, reserialized, null);
  }

  /*
   * Tests for Predicates.isNull()
   */

  public void testIsNull_apply() {
    Predicate<Integer> isNull = Predicates.isNull();
    assertTrue(isNull.apply(null));
    assertFalse(isNull.apply(1));
  }

  public void testIsNull_equality() {
    new EqualsTester()
        .addEqualityGroup(Predicates.isNull(), Predicates.isNull())
        .addEqualityGroup(Predicates.notNull())
        .testEquals();
  }

  @GwtIncompatible // SerializableTester
  public void testIsNull_serialization() {
    Predicate<String> pre = Predicates.isNull();
    Predicate<String> post = SerializableTester.reserializeAndAssert(pre);
    assertEquals(pre.apply("foo"), post.apply("foo"));
    assertEquals(pre.apply(null), post.apply(null));
  }

  public void testNotNull_apply() {
    Predicate<Integer> notNull = Predicates.notNull();
    assertFalse(notNull.apply(null));
    assertTrue(notNull.apply(1));
  }

  public void testNotNull_equality() {
    new EqualsTester()
        .addEqualityGroup(Predicates.notNull(), Predicates.notNull())
        .addEqualityGroup(Predicates.isNull())
        .testEquals();
  }

  @GwtIncompatible // SerializableTester
  public void testNotNull_serialization() {
    checkSerialization(Predicates.notNull());
  }

  public void testIn_apply() {
    Collection<Integer> nums = Arrays.asList(1, 5);
    Predicate<Integer> isOneOrFive = Predicates.in(nums);

    assertTrue(isOneOrFive.apply(1));
    assertTrue(isOneOrFive.apply(5));
    assertFalse(isOneOrFive.apply(3));
    assertFalse(isOneOrFive.apply(null));
  }

  public void testIn_equality() {
    Collection<Integer> nums = ImmutableSet.of(1, 5);
    Collection<Integer> sameOrder = ImmutableSet.of(1, 5);
    Collection<Integer> differentOrder = ImmutableSet.of(5, 1);
    Collection<Integer> differentNums = ImmutableSet.of(1, 3, 5);

    new EqualsTester()
        .addEqualityGroup(Predicates.in(nums), Predicates.in(nums),
            Predicates.in(sameOrder), Predicates.in(differentOrder))
        .addEqualityGroup(Predicates.in(differentNums))
        .testEquals();
  }

  @GwtIncompatible // SerializableTester
  public void testIn_serialization() {
    checkSerialization(Predicates.in(Arrays.asList(1, 2, 3, null)));
  }

  public void testIn_handlesNullPointerException() {
    class CollectionThatThrowsNPE<T> extends ArrayList {
      private static final long serialVersionUID = 1L;

      @Override public boolean contains(Object element) {
        Preconditions.checkNotNull(element);
        return super.contains(element);
      }
    }
    Collection<Integer> nums = new CollectionThatThrowsNPE();
    Predicate<Integer> isFalse = Predicates.in(nums);
    assertFalse(isFalse.apply(null));
  }

  public void testIn_handlesClassCastException() {
    class CollectionThatThrowsCCE<T> extends ArrayList {
      private static final long serialVersionUID = 1L;

      @Override public boolean contains(Object element) {
        throw new ClassCastException("");
      }
    }
    Collection<Integer> nums = new CollectionThatThrowsCCE();
    nums.add(3);
    Predicate<Integer> isThree = Predicates.in(nums);
    assertFalse(isThree.apply(3));
  }

  /*
   * Tests that compilation will work when applying explicit types.
   */
  @SuppressWarnings("unused") // compilation test
  public void testIn_compilesWithExplicitSupertype() {
    Collection<Number> nums = ImmutableSet.of();
    Predicate<Number> p1 = Predicates.in(nums);
    Predicate<Object> p2 = Predicates.