[MS09] Implement isSameNetwork.

Test: Old tests pass, new tests pass too.
Bug: 113554482

Change-Id: I420471853f3fab7725cba7ae500cebdce1912e43

tests/net/java/com/android/server/net/ipmemorystore/NetworkAttributesTest.java

@@ -0,0 +1,65 @@
+/*
+ * Copyright (C) 2019 The Android Open Source Project
+ *
+ * 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 com.android.server.net.ipmemorystore;
+
+import static org.junit.Assert.assertEquals;
+
+import android.net.ipmemorystore.NetworkAttributes;
+import android.support.test.filters.SmallTest;
+import android.support.test.runner.AndroidJUnit4;
+
+import org.junit.Test;
+import org.junit.runner.RunWith;
+
+import java.lang.reflect.Field;
+import java.net.Inet4Address;
+import java.net.UnknownHostException;
+import java.util.Arrays;
+
+/** Unit tests for {@link NetworkAttributes}. */
+@SmallTest
+@RunWith(AndroidJUnit4.class)
+public class NetworkAttributesTest {
+    private static final String WEIGHT_FIELD_NAME_PREFIX = "WEIGHT_";
+    private static final float EPSILON = 0.0001f;
+
+    // This is running two tests to make sure the total weight is the sum of all weights. To be
+    // sure this is not fireproof, but you'd kind of need to do it on purpose to pass.
+    @Test
+    public void testTotalWeight() throws IllegalAccessException, UnknownHostException {
+        // Make sure that TOTAL_WEIGHT is equal to the sum of the fields starting with WEIGHT_
+        float sum = 0f;
+        final Field[] fieldList = NetworkAttributes.class.getDeclaredFields();
+        for (final Field field : fieldList) {
+            if (!field.getName().startsWith(WEIGHT_FIELD_NAME_PREFIX)) continue;
+            field.setAccessible(true);
+            sum += (float) field.get(null);
+        }
+        assertEquals(sum, NetworkAttributes.TOTAL_WEIGHT, EPSILON);
+
+        // Use directly the constructor with all attributes, and make sure that when compared
+        // to itself the score is a clean 1.0f.
+        final NetworkAttributes na =
+                new NetworkAttributes(
+                        (Inet4Address) Inet4Address.getByAddress(new byte[] {1, 2, 3, 4}),
+                        "some hint",
+                        Arrays.asList(Inet4Address.getByAddress(new byte[] {5, 6, 7, 8}),
+                                Inet4Address.getByAddress(new byte[] {9, 0, 1, 2})),
+                        98);
+        assertEquals(1.0f, na.getNetworkGroupSamenessConfidence(na), EPSILON);
+    }
+}