1 /* 2 * Copyright (C) 2011 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 import com.google.common.annotations.GwtIncompatible; 21 import com.google.common.collect.testing.SampleElements; 22 import com.google.common.collect.testing.SetTestSuiteBuilder; 23 import com.google.common.collect.testing.TestSetGenerator; 24 import com.google.common.collect.testing.features.CollectionFeature; 25 import com.google.common.collect.testing.features.CollectionSize; 26 import com.google.common.collect.testing.features.SetFeature; 27 28 import junit.framework.TestCase; 29 import junit.framework.TestSuite; 30 31 import java.util.Arrays; 32 import java.util.List; 33 import java.util.Set; 34 35 /** 36 * Tests for {@link Sets#transform(Set, Sets.InvertibleFunction)}. 37 * 38 * @author Dimitris Andreou 39 */ 40 @GwtCompatible(emulated = true) 41 public class TransformedSetTest extends TestCase { 42 // Negates each integer. This is a true bijection, even considering MIN_VALUE 43 private static final Sets.InvertibleFunction<Integer, Integer> integerBijection = 44 new Sets.InvertibleFunction<Integer, Integer>() { 45 @Override public Integer apply(Integer integer) { 46 return integer != null ? -integer : null; 47 } 48 49 @Override 50 public Integer invert(Integer integer) { 51 return integer != null ? -integer : null; 52 } 53 }; 54 55 @GwtIncompatible("suite") 56 public static TestSuite suite() { 57 TestSuite suite = new TestSuite(); 58 suite.addTest(SetTestSuiteBuilder 59 .using(new TransformedIntegerSetGenerator()) 60 .named("TransformedSet") 61 .withFeatures( 62 SetFeature.GENERAL_PURPOSE, 63 CollectionFeature.ALLOWS_NULL_VALUES, 64 CollectionSize.SEVERAL) 65 .createTestSuite()); 66 return suite; 67 } 68 69 public void testSimpleCases() { 70 Set<Integer> original = Sets.newHashSet(0, 1, 2, 3); 71 Set<Integer> transformed = Sets.transform(original, integerBijection); 72 73 assertEquals(ImmutableSet.of(0, -1, -2, -3), transformed); 74 75 // adding/removing to the original, see if transformed is affected 76 assertTrue(original.remove(2)); 77 assertTrue(original.add(4)); 78 assertEquals(ImmutableSet.of(0, 1, 3, 4), original); 79 assertEquals(ImmutableSet.of(0, -1, -3, -4), transformed); 80 81 // adding/removing to the transformed, see if original is affected 82 assertTrue(transformed.remove(-1)); 83 assertTrue(transformed.add(-5)); 84 assertEquals(ImmutableSet.of(0, -3, -4, -5), transformed); 85 assertEquals(ImmutableSet.of(0, 3, 4, 5), original); 86 87 // redoing the same actions as above; no effect 88 assertFalse(transformed.remove(-1)); 89 assertFalse(transformed.add(-5)); 90 91 // they should always have the same size 92 assertEquals(original.size(), transformed.size()); 93 94 transformed.clear(); 95 assertTrue(original.isEmpty()); 96 assertTrue(transformed.isEmpty()); 97 } 98 99 public static class TransformedIntegerSetGenerator implements TestSetGenerator<Integer> { 100 @Override public Set<Integer> create(Object... elements) { 101 // Would use Collections#checkedCollection, but I get: 102 // [ERROR] The method checkedCollection(Collection, Class<Integer>) 103 // is undefined for the type Collections 104 @SuppressWarnings("unchecked") 105 Iterable<Integer> integers = (Iterable) Arrays.asList(elements); 106 107 // I invert these before adding, so that the transformed set will have 108 // the expected elements themselves, not their image under the bijection 109 Set<Integer> invertedIntegers = Sets.newHashSet(Iterables.transform(integers, 110 integerBijection.inverse())); 111 return Sets.transform(invertedIntegers, integerBijection); 112 } 113 114 @Override public Integer[] createArray(int length) { 115 return new Integer[length]; 116 } 117 118 @Override public SampleElements<Integer> samples() { 119 return new SampleElements<Integer>(-1, 0, 1, 2, 3); 120 } 121 122 @Override public Iterable<Integer> order(List<Integer> insertionOrder) { 123 throw new AssertionError(); 124 } 125 } 126 } 127
