Unit test for default partition class

Also added javadocs to DefaultPartition constructors

Change-Id: I4ba37800d61b82fabc60fd5a226850d3a3536913

@@ -32,16 +32,30 @@ public class DefaultPartition implements Partition {
     private final PartitionId id;
     private final Collection<NodeId> members;
 
-    private DefaultPartition() {
+    /**
+     * Constructs an empty partition for the serializer.
+     */
+    protected DefaultPartition() {
         id = null;
         members = null;
     }
 
+    /**
+     * Constructs a partition.
+     *
+     * @param id partition identifier
+     * @param members partition member nodes
+     */
     public DefaultPartition(PartitionId id, Collection<NodeId> members) {
         this.id = checkNotNull(id);
         this.members = ImmutableSet.copyOf(members);
     }
 
+    /**
+     * Constructs a partition that is a copy of another.
+     *
+     * @param other partition to copy
+     */
     public DefaultPartition(Partition other) {
         this.id = checkNotNull(other.getId());
         this.members = ImmutableSet.copyOf(other.getMembers());

+/*
+ * Copyright 2016 Open Networking Laboratory
+ *
+ * Licensed 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.onosproject.cluster;
+
+import java.util.Collection;
+
+import org.junit.Test;
+
+import com.google.common.collect.ImmutableSet;
+import com.google.common.testing.EqualsTester;
+
+import static org.hamcrest.MatcherAssert.assertThat;
+import static org.hamcrest.Matchers.contains;
+import static org.hamcrest.Matchers.hasSize;
+import static org.hamcrest.Matchers.is;
+import static org.hamcrest.Matchers.notNullValue;
+import static org.hamcrest.Matchers.nullValue;
+import static org.onlab.junit.ImmutableClassChecker.assertThatClassIsImmutableBaseClass;
+
+/**
+ * Unit tests for the default partition implementation.
+ */
+public class DefaultPartitionTest {
+
+    NodeId id1 = new NodeId("1");
+    NodeId id2 = new NodeId("2");
+    NodeId id3 = new NodeId("3");
+
+    PartitionId pid1 = new PartitionId(1);
+    PartitionId pid2 = new PartitionId(2);
+    PartitionId pid3 = new PartitionId(3);
+
+    DefaultPartition partition1 = new DefaultPartition(pid1, ImmutableSet.of(id1));
+    DefaultPartition sameAsPartition1 = new DefaultPartition(pid1, ImmutableSet.of(id1));
+
+    DefaultPartition partition2 = new DefaultPartition(pid2, ImmutableSet.of(id2));
+    DefaultPartition copyOfPartition2 = new DefaultPartition(partition2);
+
+    DefaultPartition partition3 = new DefaultPartition(pid3, ImmutableSet.of(id1, id2, id3));
+
+    /**
+     * Checks that the default partition implementation is an immutable
+     * base class.
+     */
+    @Test
+    public void checkImmutability() {
+        assertThatClassIsImmutableBaseClass(DefaultPartition.class);
+    }
+
+    /**
+     * Tests operation of the equals(), hashCode(), and toString() methods.
+     */
+    @Test
+    public void testEquals() {
+        new EqualsTester()
+                .addEqualityGroup(partition1, sameAsPartition1)
+                .addEqualityGroup(partition2, copyOfPartition2)
+                .addEqualityGroup(partition3)
+                .testEquals();
+    }
+
+    /**
+     * Tests that default partition objects are properly constructed.
+     */
+    @Test
+    public void testConstruction() {
+        Collection<NodeId> members = partition3.getMembers();
+        assertThat(members, notNullValue());
+        assertThat(members, hasSize(3));
+        assertThat(members, contains(id1, id2, id3));
+        assertThat(partition3.getId(), is(pid3));
+    }
+
+    /**
+     * Tests the empty defaut partition constructor.
+     */
+    @Test
+    public void testEmptyConstructor() {
+        DefaultPartition empty = new DefaultPartition();
+        assertThat(empty.getId(), nullValue());
+        assertThat(empty.getMembers(), nullValue());
+    }
+}