Add smoke test for jni library

Since the Framework net test require jni library
libnetworkstatsfactorytestjni, but the test fails to load that library
unless *all* the dependencies of that library are explicitly listed in
jni_libs, whenever any of the dependencies changes the framework net
test will start failing and it might not be catched since the change
might not related to frameworks/base. And this smoke test is aimed to
spot those native library changes and it should be stable enough to put
in global presubmit.

Bug: 124764595
Test: FrameworksNetSmokeTests
Change-Id: Id24e7f0558b5643e4ad7393e85f1f0a2bd875615

tests/net/Android.bp

@@ -49,7 +49,6 @@ java_defaults {
         "libselinux",
         "libui",
         "libutils",
-        "libvintf",
         "libvndksupport",
         "libtinyxml2",
         "libunwindstack",

tests/net/smoketest/Android.bp

+// This test exists only because the jni_libs list for these tests is difficult to
+// maintain: the test itself only depends on libnetworkstatsfactorytestjni, but the test
+// fails to load that library unless *all* the dependencies of that library are explicitly
+// listed in jni_libs. This means that whenever any of the dependencies changes the test
+// starts failing and breaking presubmits in frameworks/base. We cannot easily put
+// FrameworksNetTests into global presubmit because they are at times flaky, but this
+// test is effectively empty beyond validating that the libraries load correctly, and
+// thus should be stable enough to put in global presubmit.
+//
+// TODO: remove this hack when there is a better solution for jni_libs that includes
+// dependent libraries.
+android_test {
+    name: "FrameworksNetSmokeTests",
+    defaults: ["FrameworksNetTests-jni-defaults"],
+    srcs: ["java/SmokeTest.java"],
+    test_suites: ["device-tests"],
+}

tests/net/smoketest/AndroidManifest.xml

+<?xml version="1.0" encoding="utf-8"?>
+<!-- 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.
+-->
+
+<manifest xmlns:android="http://schemas.android.com/apk/res/android"
+        package="com.android.frameworks.tests.net.smoketest">
+    <application>
+        <uses-library android:name="android.test.runner" />
+    </application>
+
+    <instrumentation
+        android:name="androidx.test.runner.AndroidJUnitRunner"
+        android:targetPackage="com.android.frameworks.tests.net.smoketest"
+        android:label="Frameworks Networking Smoke Tests" />
+</manifest>

tests/net/smoketest/AndroidTest.xml

+<?xml version="1.0" encoding="utf-8"?>
+<!-- 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.
+-->
+<configuration description="Runs Frameworks Networking Smoke Tests.">
+    <target_preparer class="com.android.tradefed.targetprep.TestAppInstallSetup">
+        <option name="test-file-name" value="FrameworksNetSmokeTests.apk" />
+    </target_preparer>
+
+    <option name="test-suite-tag" value="apct" />
+    <option name="test-tag" value="FrameworksNetSmokeTests" />
+    <test class="com.android.tradefed.testtype.AndroidJUnitTest" >
+        <option name="package" value="com.android.frameworks.tests.net.smoketest" />
+        <option name="runner" value="androidx.test.runner.AndroidJUnitRunner" />
+        <option name="hidden-api-checks" value="false"/>
+    </test>
+</configuration>

tests/net/smoketest/java/SmokeTest.java

+/*
+ * 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;
+
+import static org.junit.Assert.assertEquals;
+
+import org.junit.Test;
+import org.junit.runner.RunWith;
+import org.junit.runners.JUnit4;
+
+@RunWith(JUnit4.class)
+public final class SmokeTest {
+
+    @Test
+    public void testLoadJni() {
+        System.loadLibrary("networkstatsfactorytestjni");
+        assertEquals(0, 0x00);
+    }
+}