001/*
002 * Copyright (C) 2015 The Guava Authors
003 *
004 * Licensed under the Apache License, Version 2.0 (the "License");
005 * you may not use this file except in compliance with the License.
006 * You may obtain a copy of the License at
007 *
008 * http://www.apache.org/licenses/LICENSE-2.0
009 *
010 * Unless required by applicable law or agreed to in writing, software
011 * distributed under the License is distributed on an "AS IS" BASIS,
012 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
013 * See the License for the specific language governing permissions and
014 * limitations under the License.
015 */
016
017package com.google.common.collect.testing.testers;
018
019import static com.google.common.collect.testing.features.CollectionSize.ZERO;
020import static com.google.common.collect.testing.features.MapFeature.ALLOWS_NULL_KEYS;
021import static com.google.common.collect.testing.features.MapFeature.ALLOWS_NULL_VALUES;
022import static com.google.common.collect.testing.features.MapFeature.SUPPORTS_PUT;
023import static org.junit.Assert.assertThrows;
024
025import com.google.common.annotations.GwtCompatible;
026import com.google.common.collect.testing.AbstractMapTester;
027import com.google.common.collect.testing.features.CollectionSize;
028import com.google.common.collect.testing.features.MapFeature;
029import com.google.common.collect.testing.testers.TestExceptions.SomeUncheckedException;
030import java.util.Map;
031import junit.framework.AssertionFailedError;
032
033/**
034 * A generic JUnit test which tests {@link Map#computeIfAbsent}. Can't be invoked directly; please
035 * see {@link com.google.common.collect.testing.MapTestSuiteBuilder}.
036 *
037 * @author Louis Wasserman
038 */
039@GwtCompatible
040public class MapComputeIfAbsentTester<K, V> extends AbstractMapTester<K, V> {
041
042  @MapFeature.Require(SUPPORTS_PUT)
043  public void testComputeIfAbsent_supportedAbsent() {
044    assertEquals(
045        "computeIfAbsent(notPresent, function) should return new value",
046        v3(),
047        getMap()
048            .computeIfAbsent(
049                k3(),
050                k -> {
051                  assertEquals(k3(), k);
052                  return v3();
053                }));
054    expectAdded(e3());
055  }
056
057  @MapFeature.Require(SUPPORTS_PUT)
058  @CollectionSize.Require(absent = ZERO)
059  public void testComputeIfAbsent_supportedPresent() {
060    assertEquals(
061        "computeIfAbsent(present, function) should return existing value",
062        v0(),
063        getMap()
064            .computeIfAbsent(
065                k0(),
066                k -> {
067                  throw new AssertionFailedError();
068                }));
069    expectUnchanged();
070  }
071
072  @MapFeature.Require(SUPPORTS_PUT)
073  public void testComputeIfAbsent_functionReturnsNullNotInserted() {
074    assertNull(
075        "computeIfAbsent(absent, returnsNull) should return null",
076        getMap()
077            .computeIfAbsent(
078                k3(),
079                k -> {
080                  assertEquals(k3(), k);
081                  return null;
082                }));
083    expectUnchanged();
084  }
085
086  @MapFeature.Require({SUPPORTS_PUT, ALLOWS_NULL_VALUES})
087  @CollectionSize.Require(absent = ZERO)
088  public void testComputeIfAbsent_nullTreatedAsAbsent() {
089    initMapWithNullValue();
090    assertEquals(
091        "computeIfAbsent(presentAssignedToNull, function) should return newValue",
092        getValueForNullKey(),
093        getMap()
094            .computeIfAbsent(
095                getKeyForNullValue(),
096                k -> {
097                  assertEquals(getKeyForNullValue(), k);
098                  return getValueForNullKey();
099                }));
100    expectReplacement(entry(getKeyForNullValue(), getValueForNullKey()));
101  }
102
103  @MapFeature.Require({SUPPORTS_PUT, ALLOWS_NULL_KEYS})
104  public void testComputeIfAbsent_nullKeySupported() {
105    getMap()
106        .computeIfAbsent(
107            null,
108            k -> {
109              assertNull(k);
110              return v3();
111            });
112    expectAdded(entry(null, v3()));
113  }
114
115  @MapFeature.Require(SUPPORTS_PUT)
116  public void testComputeIfAbsent_functionThrows() {
117    assertThrows(
118        SomeUncheckedException.class,
119        () ->
120            getMap()
121                .computeIfAbsent(
122                    k3(),
123                    k -> {
124                      assertEquals(k3(), k);
125                      throw new SomeUncheckedException();
126                    }));
127    expectUnchanged();
128  }
129
130  @MapFeature.Require(absent = SUPPORTS_PUT)
131  public void testComputeIfAbsent_unsupportedAbsent() {
132    assertThrows(
133        UnsupportedOperationException.class,
134        () ->
135            getMap()
136                .computeIfAbsent(
137                    k3(),
138                    k -> {
139                      // allowed to be called
140                      assertEquals(k3(), k);
141                      return v3();
142                    }));
143    expectUnchanged();
144  }
145
146  @MapFeature.Require(absent = SUPPORTS_PUT)
147  @CollectionSize.Require(absent = ZERO)
148  public void testComputeIfAbsent_unsupportedPresentExistingValue() {
149    try {
150      assertEquals(
151          "computeIfAbsent(present, returnsCurrentValue) should return present or throw",
152          v0(),
153          getMap()
154              .computeIfAbsent(
155                  k0(),
156                  k -> {
157                    assertEquals(k0(), k);
158                    return v0();
159                  }));
160    } catch (UnsupportedOperationException tolerated) {
161    }
162    expectUnchanged();
163  }
164
165  @MapFeature.Require(absent = SUPPORTS_PUT)
166  @CollectionSize.Require(absent = ZERO)
167  public void testComputeIfAbsent_unsupportedPresentDifferentValue() {
168    try {
169      assertEquals(
170          "computeIfAbsent(present, returnsDifferentValue) should return present or throw",
171          v0(),
172          getMap()
173              .computeIfAbsent(
174                  k0(),
175                  k -> {
176                    assertEquals(k0(), k);
177                    return v3();
178                  }));
179    } catch (UnsupportedOperationException tolerated) {
180    }
181    expectUnchanged();
182  }
183
184  @MapFeature.Require(value = SUPPORTS_PUT, absent = ALLOWS_NULL_KEYS)
185  public void testComputeIfAbsent_nullKeyUnsupported() {
186    assertThrows(
187        NullPointerException.class,
188        () ->
189            getMap()
190                .computeIfAbsent(
191                    null,
192                    k -> {
193                      assertNull(k);
194                      return v3();
195                    }));
196    expectUnchanged();
197    expectNullKeyMissingWhenNullKeysUnsupported(
198        "Should not contain null key after unsupported computeIfAbsent(null, function)");
199  }
200}