Implement REST API of policy

Change-Id: I46f5a3cd6d66cf7a3a90a5d153b3878fdf5cbd31
diff --git a/impl/src/test/java/org/onosproject/segmentrouting/policy/api/DropPolicyCodecTest.java b/impl/src/test/java/org/onosproject/segmentrouting/policy/api/DropPolicyCodecTest.java
new file mode 100644
index 0000000..5d95625
--- /dev/null
+++ b/impl/src/test/java/org/onosproject/segmentrouting/policy/api/DropPolicyCodecTest.java
@@ -0,0 +1,68 @@
+/*
+ * Copyright 2021-present Open Networking Foundation
+ *
+ * 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.segmentrouting.policy.api;
+
+import com.fasterxml.jackson.databind.JsonNode;
+import com.fasterxml.jackson.databind.ObjectMapper;
+import com.fasterxml.jackson.databind.node.ObjectNode;
+import junit.framework.TestCase;
+import org.junit.Before;
+import org.junit.Test;
+import org.onosproject.codec.CodecContext;
+import org.onosproject.codec.JsonCodec;
+import org.onosproject.codec.impl.MockCodecContext;
+
+import java.io.InputStream;
+
+public class DropPolicyCodecTest extends TestCase {
+    private DropPolicy dropPolicy;
+
+    private CodecContext context;
+    private JsonCodec<DropPolicy> codec;
+
+    @Before
+    public void setUp() throws Exception {
+        context = new MockCodecContext();
+        codec = new DropPolicyCodec();
+
+        dropPolicy = new DropPolicy();
+    }
+
+    @Test
+    public void testEncode() throws Exception {
+        ObjectMapper mapper = new ObjectMapper();
+
+        InputStream jsonStream1 = RedirectPolicyCodecTest.class.getResourceAsStream("/droppolicy.json");
+        JsonNode expected = mapper.readTree(jsonStream1);
+
+        JsonNode actual = codec.encode(dropPolicy, context);
+
+        assertEquals(expected.get(RedirectPolicyCodec.POLICY_ID), actual.get(RedirectPolicyCodec.POLICY_ID));
+        assertEquals(expected.get(RedirectPolicyCodec.POLICY_TYPE), actual.get(RedirectPolicyCodec.POLICY_TYPE));
+    }
+
+    @Test
+    public void testDecode() throws Exception  {
+        ObjectMapper mapper = new ObjectMapper();
+
+        InputStream jsonStream1 = RedirectPolicyCodecTest.class.getResourceAsStream("/droppolicy.json");
+        ObjectNode json = mapper.readTree(jsonStream1).deepCopy();
+
+        DropPolicy actual = codec.decode(json, context);
+
+        assertEquals(dropPolicy, actual);
+    }
+}
\ No newline at end of file