[ONOS-4438] Add codecs for mastership REST API

Add codecs for RoleInfo, MastershipTerm and MastershipRole.

Change-Id: I1135c7fc0ed591446d6268229b54fda70391fdb9
diff --git a/core/common/src/test/java/org/onosproject/codec/impl/RoleInfoCodecTest.java b/core/common/src/test/java/org/onosproject/codec/impl/RoleInfoCodecTest.java
new file mode 100644
index 0000000..85c13d0
--- /dev/null
+++ b/core/common/src/test/java/org/onosproject/codec/impl/RoleInfoCodecTest.java
@@ -0,0 +1,166 @@
+/*
+ * Copyright 2016-present 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.codec.impl;
+
+import com.fasterxml.jackson.databind.JsonNode;
+import com.fasterxml.jackson.databind.node.ObjectNode;
+import com.google.common.collect.ImmutableList;
+import org.apache.commons.lang3.StringUtils;
+import org.hamcrest.Description;
+import org.hamcrest.TypeSafeDiagnosingMatcher;
+import org.junit.Before;
+import org.junit.Test;
+import org.onosproject.cluster.NodeId;
+import org.onosproject.cluster.RoleInfo;
+import org.onosproject.codec.JsonCodec;
+
+import java.io.IOException;
+import java.io.InputStream;
+import java.util.List;
+
+import static org.hamcrest.MatcherAssert.assertThat;
+import static org.hamcrest.Matchers.is;
+import static org.hamcrest.Matchers.notNullValue;
+
+/**
+ * Unit tests for role info codec.
+ */
+public final class RoleInfoCodecTest {
+
+    MockCodecContext context;
+    JsonCodec<RoleInfo> roleInfoCodec;
+
+    @Before
+    public void setUp() {
+        context = new MockCodecContext();
+        roleInfoCodec = context.codec(RoleInfo.class);
+        assertThat(roleInfoCodec, notNullValue());
+    }
+
+    /**
+     * Tests encoding of a role info object.
+     */
+    @Test
+    public void testRoleInfoEncode() {
+        NodeId masterNodeId = NodeId.nodeId("1");
+        NodeId backupNodeId1 = NodeId.nodeId("1");
+        NodeId backupNodeId2 = NodeId.nodeId("2");
+        NodeId backupNodeId3 = NodeId.nodeId("3");
+        List<NodeId> backupNodeIds =
+                ImmutableList.of(backupNodeId1, backupNodeId2, backupNodeId3);
+
+        RoleInfo roleInfo = new RoleInfo(masterNodeId, backupNodeIds);
+        ObjectNode roleInfoJson = roleInfoCodec.encode(roleInfo, context);
+        assertThat(roleInfoJson, RoleInfoJsonMatcher.matchesRoleInfo(roleInfo));
+    }
+
+    /**
+     * Tests decoding of a role info JSON object.
+     */
+    @Test
+    public void testRoleInfoDecode() throws IOException {
+        RoleInfo roleInfo = getRoleInfo("RoleInfo.json");
+
+        assertThat(roleInfo.backups().size(), is(3));
+
+        assertThat(roleInfo.master().id(), is("1"));
+
+        List<NodeId> backups = roleInfo.backups();
+        assertThat(backups.contains(NodeId.nodeId("2")), is(true));
+        assertThat(backups.contains(NodeId.nodeId("3")), is(true));
+        assertThat(backups.contains(NodeId.nodeId("4")), is(true));
+    }
+
+    /**
+     * Hamcrest matcher for role info.
+     */
+    private static final class RoleInfoJsonMatcher extends TypeSafeDiagnosingMatcher<JsonNode> {
+
+        private final RoleInfo roleInfo;
+
+        private RoleInfoJsonMatcher(RoleInfo roleInfo) {
+            this.roleInfo = roleInfo;
+        }
+
+        @Override
+        protected boolean matchesSafely(JsonNode jsonNode, Description description) {
+
+            // check master node identifier
+            String jsonNodeId = jsonNode.get("master") != null ? jsonNode.get("master").asText() : null;
+            String nodeId = roleInfo.master().id();
+            if (!StringUtils.equals(jsonNodeId, nodeId)) {
+                description.appendText("master's node id was " + jsonNodeId);
+                return false;
+            }
+
+            // check backup nodes size
+            JsonNode jsonBackupNodeIds = jsonNode.get("backups");
+            if (jsonBackupNodeIds.size() != roleInfo.backups().size()) {
+                description.appendText("backup nodes size was " + jsonBackupNodeIds.size());
+                return false;
+            }
+
+
+            // check backup nodes' identifier
+            for (NodeId backupNodeId : roleInfo.backups()) {
+                boolean backupFound = false;
+                for (int idx = 0; idx < jsonBackupNodeIds.size(); idx++) {
+                    if (backupNodeId.id().equals(jsonBackupNodeIds.get(idx).asText())) {
+                        backupFound = true;
+                        break;
+                    }
+                }
+                if (!backupFound) {
+                    description.appendText("backup not found " + backupNodeId.id());
+                    return false;
+                }
+            }
+
+            return true;
+        }
+
+        @Override
+        public void describeTo(Description description) {
+            description.appendText(roleInfo.toString());
+        }
+
+        /**
+         * Factory to allocate a role info.
+         *
+         * @param roleInfo role info object we are looking for
+         * @return matcher
+         */
+        static RoleInfoJsonMatcher matchesRoleInfo(RoleInfo roleInfo) {
+            return new RoleInfoJsonMatcher(roleInfo);
+        }
+    }
+
+    /**
+     * Reads in a role info from the given resource and decodes it.
+     *
+     * @param resourceName resource to use to read the JSON for the rule
+     * @return decoded roleInfo
+     * @throws IOException if processing the resource fails
+     */
+    private RoleInfo getRoleInfo(String resourceName) throws IOException {
+        InputStream jsonStream = RoleInfoCodecTest.class.getResourceAsStream(resourceName);
+        JsonNode json = context.mapper().readTree(jsonStream);
+        assertThat(json, notNullValue());
+        RoleInfo roleInfo = roleInfoCodec.decode((ObjectNode) json, context);
+        assertThat(roleInfo, notNullValue());
+        return roleInfo;
+    }
+}