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      1 /*
      2  * Copyright (C) 2009 The Guava Authors
      3  *
      4  * Licensed under the Apache License, Version 2.0 (the "License");
      5  * you may not use this file except in compliance with the License.
      6  * You may obtain a copy of the License at
      7  *
      8  * http://www.apache.org/licenses/LICENSE-2.0
      9  *
     10  * Unless required by applicable law or agreed to in writing, software
     11  * distributed under the License is distributed on an "AS IS" BASIS,
     12  * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
     13  * See the License for the specific language governing permissions and
     14  * limitations under the License.
     15  */
     16 
     17 package com.google.common.collect;
     18 
     19 import com.google.common.annotations.GwtCompatible;
     20 
     21 import junit.framework.AssertionFailedError;
     22 import junit.framework.TestCase;
     23 
     24 /**
     25  * Unit test for {@link ComparisonChain}.
     26  *
     27  * @author Kevin Bourrillion
     28  */
     29 @GwtCompatible
     30 public class ComparisonChainTest extends TestCase {
     31   private static final DontCompareMe DONT_COMPARE_ME = new DontCompareMe();
     32 
     33   private static class DontCompareMe implements Comparable<DontCompareMe> {
     34     @Override
     35     public int compareTo(DontCompareMe o) {
     36       throw new AssertionFailedError();
     37     }
     38   }
     39 
     40   public void testDegenerate() {
     41     // kinda bogus, but who cares?
     42     assertEquals(0, ComparisonChain.start().result());
     43   }
     44 
     45   public void testOneEqual() {
     46     assertEquals(0, ComparisonChain.start()
     47         .compare("a", "a")
     48         .result());
     49   }
     50 
     51   public void testOneEqualUsingComparator() {
     52     assertEquals(0, ComparisonChain.start()
     53         .compare("a", "A", String.CASE_INSENSITIVE_ORDER)
     54         .result());
     55   }
     56 
     57   public void testManyEqual() {
     58     assertEquals(0, ComparisonChain.start()
     59         .compare(1, 1)
     60         .compare(1L, 1L)
     61         .compareFalseFirst(true, true)
     62         .compare(1.0, 1.0)
     63         .compare(1.0f, 1.0f)
     64         .compare("a", "a", Ordering.usingToString())
     65         .result());
     66   }
     67 
     68   public void testShortCircuitLess() {
     69     assertTrue(ComparisonChain.start()
     70         .compare("a", "b")
     71         .compare(DONT_COMPARE_ME, DONT_COMPARE_ME)
     72         .result() < 0);
     73   }
     74 
     75   public void testShortCircuitGreater() {
     76     assertTrue(ComparisonChain.start()
     77         .compare("b", "a")
     78         .compare(DONT_COMPARE_ME, DONT_COMPARE_ME)
     79         .result() > 0);
     80   }
     81 
     82   public void testShortCircuitSecondStep() {
     83     assertTrue(ComparisonChain.start()
     84         .compare("a", "a")
     85         .compare("a", "b")
     86         .compare(DONT_COMPARE_ME, DONT_COMPARE_ME)
     87         .result() < 0);
     88   }
     89 
     90   public void testCompareFalseFirst() {
     91     assertTrue(ComparisonChain.start().compareFalseFirst(true, true).result() == 0);
     92     assertTrue(ComparisonChain.start().compareFalseFirst(true, false).result() > 0);
     93     assertTrue(ComparisonChain.start().compareFalseFirst(false, true).result() < 0);
     94     assertTrue(ComparisonChain.start().compareFalseFirst(false, false).result() == 0);
     95   }
     96 
     97   public void testCompareTrueFirst() {
     98     assertTrue(ComparisonChain.start().compareTrueFirst(true, true).result() == 0);
     99     assertTrue(ComparisonChain.start().compareTrueFirst(true, false).result() < 0);
    100     assertTrue(ComparisonChain.start().compareTrueFirst(false, true).result() > 0);
    101     assertTrue(ComparisonChain.start().compareTrueFirst(false, false).result() == 0);
    102   }
    103 }
    104