Fix MapEntry implementation that was not compatible with java Map.Entry

src/main/java/org/assertj/core/data/MapEntry.java

@@ -12,19 +12,19 @@
  */
 package org.assertj.core.data;
 
-import static org.assertj.core.util.Objects.*;
 import static org.assertj.core.presentation.DefaultToString.toStringOf;
 import static org.assertj.core.presentation.StandardRepresentation.STANDARD_REPRESENTATION;
 
 import java.util.Map;
+import java.util.Objects;
 
 /**
  * Understands an entry in a <code>{@link Map}</code>.
  *
  * @author Yvonne Wang
  */
-public class MapEntry<K, V> implements Map.Entry<K, V>{
-  
+public class MapEntry<K, V> implements Map.Entry<K, V> {
+
   public final K key;
   public final V value;
 
@@ -35,7 +35,7 @@ public class MapEntry<K, V> implements Map.Entry<K, V>{
    * @param value the value of the entry to create.
    * @return the created {@code MapEntry}.
    */
-  public static <K,V> MapEntry<K, V> entry(K key, V value) {
+  public static <K, V> MapEntry<K, V> entry(K key, V value) {
     return new MapEntry<>(key, value);
   }
 
@@ -45,20 +45,16 @@ private MapEntry(K key, V value) {
   }
 
   @Override
-  public boolean equals(Object obj) {
-    if (this == obj) return true; 
-    if (!(obj instanceof MapEntry)) return false;
-    @SuppressWarnings("rawtypes")
-    MapEntry other = (MapEntry) obj;
-    return areEqual(key, other.key) && areEqual(value, other.value);
+  public boolean equals(Object object) {
+    if (!(object instanceof Map.Entry)) return false;
+    Map.Entry<?, ?> that = (Map.Entry<?, ?>) object;
+    return Objects.equals(this.getKey(), that.getKey())
+           && Objects.equals(this.getValue(), that.getValue());
   }
 
   @Override
   public int hashCode() {
-    int result = 1;
-    result = HASH_CODE_PRIME * result + hashCodeFor(key);
-    result = HASH_CODE_PRIME * result + hashCodeFor(value);
-    return result;
+    return Objects.hashCode(getKey()) ^ Objects.hashCode(getValue());
   }
 
   @Override
@@ -75,7 +71,7 @@ public K getKey() {
   public V getValue() {
     return value;
   }
-  
+
   /**
    * Always throws <tt>UnsupportedOperationException</tt>,
    * as this class represents an <i>immutable</i> map entry.
@@ -86,6 +82,6 @@ public V getValue() {
    */
   @Override
   public V setValue(V value) {
-      throw new UnsupportedOperationException();
+    throw new UnsupportedOperationException();
   }
 }

src/test/java/org/assertj/core/data/MapEntry_equals_hashCode_Test.java

@@ -12,13 +12,18 @@
  */
 package org.assertj.core.data;
 
+import static java.util.Collections.singletonMap;
 import static org.assertj.core.api.Assertions.assertThat;
 import static org.assertj.core.data.MapEntry.entry;
-import static org.assertj.core.test.EqualsHashCodeContractAssert.*;
+import static org.assertj.core.test.EqualsHashCodeContractAssert.assertEqualsIsReflexive;
+import static org.assertj.core.test.EqualsHashCodeContractAssert.assertEqualsIsSymmetric;
+import static org.assertj.core.test.EqualsHashCodeContractAssert.assertEqualsIsTransitive;
+import static org.assertj.core.test.EqualsHashCodeContractAssert.assertMaintainsEqualsAndHashCodeContract;
 
+import java.util.Map.Entry;
 
-import org.assertj.core.data.MapEntry;
-import org.junit.*;
+import org.junit.BeforeClass;
+import org.junit.Test;
 
 /**
  * Tests for {@link MapEntry#equals(Object)} and {@link MapEntry#hashCode()}.
@@ -27,10 +32,12 @@
  */
 public class MapEntry_equals_hashCode_Test {
   private static MapEntry<String, String> entry;
+  private static Entry<String, String> javaEntry;
 
   @BeforeClass
   public static void setUpOnce() {
     entry = entry("key", "value");
+    javaEntry = singletonMap("key", "value").entrySet().iterator().next();
   }
 
   @Test
@@ -67,4 +74,20 @@ public void should_not_be_equal_to_null() {
   public void should_not_be_equal_to_MapEntry_with_different_value() {
     assertThat(entry.equals(entry("key0", "value0"))).isFalse();
   }
+
+  @Test
+  public void should_have_symmetric_equals_with_java_MapEntry() {
+    assertEqualsIsSymmetric(javaEntry, entry);
+  }
+
+  @Test
+  public void should_maintain_equals_and_hashCode_contract_with_java_MapEntry() {
+    assertMaintainsEqualsAndHashCodeContract(javaEntry, entry);
+  }
+
+  @Test
+  public void should_have_transitive_equals_with_java_MapEntry() {
+    Entry<String, String> javaEntry2 = singletonMap("key", "value").entrySet().iterator().next();
+    assertEqualsIsTransitive(entry, javaEntry, javaEntry2);
+  }
 }