[COLLECTIONS-811] Integrate Guava Testlib tests for Apache Commons Co…

…llections

pom.xml

@@ -524,6 +524,12 @@
       <version>1.15</version>
       <optional>true</optional>
     </dependency>
+    <dependency>
+      <groupId>com.google.guava</groupId>
+      <artifactId>guava-testlib</artifactId>
+      <version>31.1-jre</version>
+      <scope>test</scope>
+    </dependency>
   </dependencies>
 
   <distributionManagement>

src/changes/changes.xml

@@ -134,6 +134,9 @@
     <action dev="ggregory" type="add" due-to="Gary Gregory">
       Add singleton ObjectToStringComparator.INSTANCE.
     </action>
+    <action issue="COLLECTIONS-811" dev="kinow" type="add">
+      Integrate Guava testlib tests.
+    </action>
     <!-- UPDATE -->
     <action type="update" dev="kinow" due-to="Dependabot, Gary Gregory">
       Bump actions/setup-java from 1.4.0 to 3 #174 #177 #186 #224 #298.

src/test/java/org/apache/commons/collections4/GuavaTestlibTest.java

@@ -0,0 +1,76 @@
+/*
+ * Licensed to the Apache Software Foundation (ASF) under one or more
+ * contributor license agreements.  See the NOTICE file distributed with
+ * this work for additional information regarding copyright ownership.
+ * The ASF licenses this file to You 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 org.apache.commons.collections4;
+
+import java.util.Map;
+import java.util.function.Supplier;
+
+import org.apache.commons.collections4.map.HashedMap;
+import org.apache.commons.collections4.map.LRUMap;
+import org.apache.commons.collections4.map.LinkedMap;
+import org.apache.commons.collections4.map.ReferenceMap;
+
+import com.google.common.collect.testing.MapTestSuiteBuilder;
+import com.google.common.collect.testing.TestStringMapGenerator;
+import com.google.common.collect.testing.features.CollectionFeature;
+import com.google.common.collect.testing.features.CollectionSize;
+import com.google.common.collect.testing.features.MapFeature;
+
+import junit.framework.Test;
+import junit.framework.TestCase;
+import junit.framework.TestSuite;
+
+/**
+ * This test uses Google's Guava Testlib testing libraries to validate the
+ * contract of collection classes in Commons Collections. This was introduced
+ * after COLLECTIONS-802, where the issue reported was found with Testlib,
+ * with thanks to Ben Manes.
+ *
+ * @since 4.5.0
+ * @see <a href="https://github.com/google/guava/tree/master/guava-testlib">https://github.com/google/guava/tree/master/guava-testlib</a>
+ * @see <a href="https://issues.apache.org/jira/browse/COLLECTIONS-802">https://issues.apache.org/jira/browse/COLLECTIONS-802</a>
+ */
+public final class GuavaTestlibTest extends TestCase {
+
+    public static Test suite() {
+        TestSuite test = new TestSuite();
+        test.addTest(suite("HashedMap", HashedMap::new));
+        test.addTest(suite("LinkedMap", LinkedMap::new));
+        test.addTest(suite("LRUMap", LRUMap::new));
+        test.addTest(suite("ReferenceMap", ReferenceMap::new));
+        return test;
+    }
+
+    public static Test suite(String name, Supplier<Map<String, String>> factory) {
+        return MapTestSuiteBuilder.using(new TestStringMapGenerator() {
+            @Override
+            protected Map<String, String> create(Map.Entry<String, String>[] entries) {
+                Map<String, String> map = factory.get();
+                for (Map.Entry<String, String> entry : entries) {
+                    map.put(entry.getKey(), entry.getValue());
+                }
+                return map;
+            }
+        })
+                .named(name)
+                .withFeatures(
+                        CollectionSize.ANY, MapFeature.GENERAL_PURPOSE,
+                        MapFeature.ALLOWS_ANY_NULL_QUERIES, CollectionFeature.SUPPORTS_ITERATOR_REMOVE)
+                .createTestSuite();
+    }
+}