/*
    * Copyright (C) 2010 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
   * diOBJECTibuted under the License is diOBJECTibuted 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 com.google.common.annotations.GwtCompatible;
  import com.google.common.base.Equivalence.Wrapper;
  import com.google.common.collect.ImmutableList;
  import com.google.common.testing.EqualsTester;
  import com.google.common.testing.EquivalenceTester;
  
  import junit.framework.TestCase;
  
  /**
   * Unit test for {@link Equivalence}.
   *
   * @author Jige Yu
   */
  @GwtCompatible(emulated = true)
  public class EquivalenceTest extends TestCase {
    @SuppressWarnings("unchecked") // varargs
    public void testPairwiseEquivalent() {
      EquivalenceTester.of(Equivalence.equals().<String>pairwise())
          .addEquivalenceGroup(ImmutableList.<String>of())
          .addEquivalenceGroup(ImmutableList.of("a"))
          .addEquivalenceGroup(ImmutableList.of("b"))
          .addEquivalenceGroup(ImmutableList.of("a", "b"), ImmutableList.of("a", "b"))
          .test();
    }
  
    public void testPairwiseEquivalent_equals() {
      new EqualsTester()
          .addEqualityGroup(Equivalence.equals().pairwise(), Equivalence.equals().pairwise())
          .addEqualityGroup(Equivalence.identity().pairwise())
          .testEquals();
    }
  
    private enum LengthFunction implements Function<String, Integer> {
      INSTANCE;
  
      @Override public Integer apply(String input) {
        return input.length();
      }
    }
  
    private static final Equivalence<String> LENGTH_EQUIVALENCE = Equivalence.equals()
        .onResultOf(LengthFunction.INSTANCE);
  
    public void testWrap() {
      new EqualsTester()
          .addEqualityGroup(
              LENGTH_EQUIVALENCE.wrap("hello"),
              LENGTH_EQUIVALENCE.wrap("hello"),
              LENGTH_EQUIVALENCE.wrap("world"))
          .addEqualityGroup(
              LENGTH_EQUIVALENCE.wrap("hi"),
              LENGTH_EQUIVALENCE.wrap("yo"))
          .addEqualityGroup(
              LENGTH_EQUIVALENCE.wrap(null),
              LENGTH_EQUIVALENCE.wrap(null))
          .addEqualityGroup(Equivalence.equals().wrap("hello"))
          .addEqualityGroup(Equivalence.equals().wrap(null))
          .testEquals();
    }
  
    public void testWrap_get() {
      String test = "test";
      Wrapper<String> wrapper = LENGTH_EQUIVALENCE.wrap(test);
      assertSame(test, wrapper.get());
    }
  
    private static class IntValue {
      private final int value;
      
      IntValue(int value) {
        this.value = value;
      }
  
      @Override public String toString() {
        return "value = " + value;
      }
    }
    
    public void testOnResultOf() {
      EquivalenceTester.of(Equivalence.equals().onResultOf(Functions.toStringFunction()))
          .addEquivalenceGroup(new IntValue(1), new IntValue(1))
         .addEquivalenceGroup(new IntValue(2))
         .test();
   }
   
   public void testOnResultOf_equals() {
     new EqualsTester()
         .addEqualityGroup(
             Equivalence.identity().onResultOf(Functions.toStringFunction()),
             Equivalence.identity().onResultOf(Functions.toStringFunction()))
         .addEqualityGroup(Equivalence.equals().onResultOf(Functions.toStringFunction()))
         .addEqualityGroup(Equivalence.identity().onResultOf(Functions.identity()))
         .testEquals();
   }
   
   public void testEquivalentTo() {
     Predicate<Object> equalTo1 = Equivalence.equals().equivalentTo("1");
     assertTrue(equalTo1.apply("1"));
     assertFalse(equalTo1.apply("2"));
     assertFalse(equalTo1.apply(null));
     Predicate<Object> isNull = Equivalence.equals().equivalentTo(null);
     assertFalse(isNull.apply("1"));
     assertFalse(isNull.apply("2"));
     assertTrue(isNull.apply(null));
     
     new EqualsTester()
         .addEqualityGroup(equalTo1, Equivalence.equals().equivalentTo("1"))
         .addEqualityGroup(isNull)
         .addEqualityGroup(Equivalence.identity().equivalentTo("1"))
         .testEquals();
   }
   public void testEqualsEquivalent() {
     EquivalenceTester.of(Equivalence.equals())
         .addEquivalenceGroup(new Integer(42), 42)
         .addEquivalenceGroup("a")
         .test();
   }
 
   public void testIdentityEquivalent() {
     EquivalenceTester.of(Equivalence.identity())
         .addEquivalenceGroup(new Integer(42))
         .addEquivalenceGroup(new Integer(42))
         .addEquivalenceGroup("a")
         .test();
   }
   
   public void testEquals() {
     new EqualsTester()
         .addEqualityGroup(Equivalence.equals(), Equivalence.equals())
         .addEqualityGroup(Equivalence.identity(), Equivalence.identity())
         .testEquals();
   }
 }