Add test for getStartUser(), getEndUser() and createForUser()

- Follow-up commit will modify getStartUser() and getEndUser(),
to make sure the result is consistent, add test before changing
getStartUser() and getEndUser().
- Add a test for createForUser() to ensure the last uid of
the previous user is smaller than the first uid of the next user.
- Move this test file to tests/net/common, so that it can be run
in CTS.

Bug: 170598012
Test: atest FrameworksNetTests:UidRangeTest
      CtsNetTestCasesLatestSdk:UidRangeTest
      Also run above tests on Q and R devices.
Change-Id: I8b146aa14b50911e50a39f266e8d8dc17df853b2

tests/net/common/java/android/net/UidRangeTest.java

@@ -0,0 +1,113 @@
+/*
+ * Copyright (C) 2016 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 android.net;
+
+import static android.os.UserHandle.MIN_SECONDARY_USER_ID;
+import static android.os.UserHandle.SYSTEM;
+import static android.os.UserHandle.USER_SYSTEM;
+import static android.os.UserHandle.getUid;
+
+import static org.junit.Assert.assertEquals;
+import static org.junit.Assert.assertTrue;
+import static org.junit.Assert.fail;
+
+import android.os.Build;
+import android.os.UserHandle;
+
+import androidx.test.filters.SmallTest;
+import androidx.test.runner.AndroidJUnit4;
+
+import com.android.testutils.DevSdkIgnoreRule;
+import com.android.testutils.DevSdkIgnoreRule.IgnoreUpTo;
+
+import org.junit.Rule;
+import org.junit.Test;
+import org.junit.runner.RunWith;
+
+@RunWith(AndroidJUnit4.class)
+@SmallTest
+public class UidRangeTest {
+
+    /*
+     * UidRange is no longer passed to netd. UID ranges between the framework and netd are passed as
+     * UidRangeParcel objects.
+     */
+
+    @Rule
+    public final DevSdkIgnoreRule mIgnoreRule = new DevSdkIgnoreRule();
+
+    @Test
+    public void testSingleItemUidRangeAllowed() {
+        new UidRange(123, 123);
+        new UidRange(0, 0);
+        new UidRange(Integer.MAX_VALUE, Integer.MAX_VALUE);
+    }
+
+    @Test
+    public void testNegativeUidsDisallowed() {
+        try {
+            new UidRange(-2, 100);
+            fail("Exception not thrown for negative start UID");
+        } catch (IllegalArgumentException expected) {
+        }
+
+        try {
+            new UidRange(-200, -100);
+            fail("Exception not thrown for negative stop UID");
+        } catch (IllegalArgumentException expected) {
+        }
+    }
+
+    @Test
+    public void testStopLessThanStartDisallowed() {
+        final int x = 4195000;
+        try {
+            new UidRange(x, x - 1);
+            fail("Exception not thrown for negative-length UID range");
+        } catch (IllegalArgumentException expected) {
+        }
+    }
+
+    @Test
+    public void testGetStartAndEndUser() throws Exception {
+        final UidRange uidRangeOfPrimaryUser = new UidRange(
+                getUid(USER_SYSTEM, 10000), getUid(USER_SYSTEM, 10100));
+        final UidRange uidRangeOfSecondaryUser = new UidRange(
+                getUid(MIN_SECONDARY_USER_ID, 10000), getUid(MIN_SECONDARY_USER_ID, 10100));
+        assertEquals(USER_SYSTEM, uidRangeOfPrimaryUser.getStartUser());
+        assertEquals(USER_SYSTEM, uidRangeOfPrimaryUser.getEndUser());
+        assertEquals(MIN_SECONDARY_USER_ID, uidRangeOfSecondaryUser.getStartUser());
+        assertEquals(MIN_SECONDARY_USER_ID, uidRangeOfSecondaryUser.getEndUser());
+
+        final UidRange uidRangeForDifferentUsers = new UidRange(
+                getUid(USER_SYSTEM, 10000), getUid(MIN_SECONDARY_USER_ID, 10100));
+        assertEquals(USER_SYSTEM, uidRangeOfPrimaryUser.getStartUser());
+        assertEquals(MIN_SECONDARY_USER_ID, uidRangeOfSecondaryUser.getEndUser());
+    }
+
+    @Test @IgnoreUpTo(Build.VERSION_CODES.R)
+    public void testCreateForUser() throws Exception {
+        final UidRange uidRangeOfPrimaryUser = UidRange.createForUser(SYSTEM);
+        final UidRange uidRangeOfSecondaryUser = UidRange.createForUser(
+                UserHandle.of(USER_SYSTEM + 1));
+        assertTrue(uidRangeOfPrimaryUser.stop < uidRangeOfSecondaryUser.start);
+        assertEquals(USER_SYSTEM, uidRangeOfPrimaryUser.getStartUser());
+        assertEquals(USER_SYSTEM, uidRangeOfPrimaryUser.getEndUser());
+        assertEquals(USER_SYSTEM + 1, uidRangeOfSecondaryUser.getStartUser());
+        assertEquals(USER_SYSTEM + 1, uidRangeOfSecondaryUser.getEndUser());
+    }
+}