Add more unit tests for Pi* classes

Change-Id: Idaee25730bd39f10f2f3e66f9e3d2a29061d5b30
diff --git a/core/api/src/test/java/org/onosproject/net/pi/runtime/PiActionGroupMemberIdTest.java b/core/api/src/test/java/org/onosproject/net/pi/runtime/PiActionGroupMemberIdTest.java
new file mode 100644
index 0000000..008a74e
--- /dev/null
+++ b/core/api/src/test/java/org/onosproject/net/pi/runtime/PiActionGroupMemberIdTest.java
@@ -0,0 +1,67 @@
+/*
+ * Copyright 2017-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.net.pi.runtime;
+
+import com.google.common.testing.EqualsTester;
+import org.junit.Test;
+
+import static org.hamcrest.MatcherAssert.assertThat;
+import static org.hamcrest.Matchers.is;
+import static org.hamcrest.Matchers.notNullValue;
+import static org.onlab.junit.ImmutableClassChecker.assertThatClassIsImmutable;
+
+/**
+ * Unit tests for PiActionGroupMemberId class.
+ */
+public class PiActionGroupMemberIdTest {
+
+    final PiActionGroupMemberId piActionGroupMemberId1 = PiActionGroupMemberId.of(10);
+    final PiActionGroupMemberId sameAsPiActionGroupMemberId1 = PiActionGroupMemberId.of(10);
+    final PiActionGroupMemberId piActionGroupMemberId2 = PiActionGroupMemberId.of(20);
+
+    /**
+     * Checks that the PiActionGroupMemberId class is immutable.
+     */
+    @Test
+    public void testImmutability() {
+
+        assertThatClassIsImmutable(PiActionGroupMemberId.class);
+    }
+
+    /**
+     * Checks the operation of equals(), hashCode() and toString() methods.
+     */
+    @Test
+    public void testEquals() {
+
+        new EqualsTester()
+                .addEqualityGroup(piActionGroupMemberId1, sameAsPiActionGroupMemberId1)
+                .addEqualityGroup(piActionGroupMemberId2)
+                .testEquals();
+    }
+
+    /**
+     * Checks the methods of PiActionGroupMemberId.
+     */
+    @Test
+    public void testMethods() {
+
+        assertThat(piActionGroupMemberId1, is(notNullValue()));
+        assertThat(piActionGroupMemberId1.type(), is(PiTableAction.Type.GROUP_MEMBER_ID));
+        assertThat(piActionGroupMemberId1.id(), is(10));
+    }
+}