Test the JNI support in Apk-in-Apexes.

This CL is introducing the use of JNI in Apk-in-Apexes.
A host driven test is added in host/ApkInApexTests which runs a newly
added native test in app/ApkInApexTests which runs on device.

Bug: 144547772
Test: atest apex_apkinapex_tests:ApkInApexTests

Change-Id: I05da4fff0f5aad2d178f07806e634189a87afa56
diff --git a/tests/Android.bp b/tests/Android.bp
index f098b4a..438a799 100644
--- a/tests/Android.bp
+++ b/tests/Android.bp
@@ -252,10 +252,28 @@
     ],
 }
 
+cc_test_library {
+    name: "libApkInApex_jni",
+    gtest: false,
+    srcs: [
+        "app/jni/com_android_tests_apex_app_ApkInApexTests.cpp",
+    ],
+    cflags: [
+        "-Wall",
+        "-Werror",
+    ],
+    header_libs: ["jni_headers"],
+    stl: "c++_shared",
+    sdk_version: "current",
+}
+
 android_test_helper_app {
     name: "apex_apkinapex_tests_app",
     manifest: "app/ApkInApexTests_AndroidManifest.xml",
     srcs: ["app/src/**/ApkInApexTests.java"],
+    jni_libs: [
+        "libApkInApex_jni",
+    ],
     static_libs: ["androidx.test.rules", "cts-install-lib", "cts-rollback-lib", "testng"],
     test_suites: ["general-tests"],
 }
diff --git a/tests/app/jni/com_android_tests_apex_app_ApkInApexTests.cpp b/tests/app/jni/com_android_tests_apex_app_ApkInApexTests.cpp
new file mode 100644
index 0000000..a948c7a
--- /dev/null
+++ b/tests/app/jni/com_android_tests_apex_app_ApkInApexTests.cpp
@@ -0,0 +1,48 @@
+/*
+ * Copyright 2022 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.
+ *
+ */
+
+#include <jni.h>
+
+namespace {
+
+bool fakeMethod() { return true; }
+
+jint com_android_tests_apex_app_nativeFakeMethod(JNIEnv * /*env*/,
+                                                 jclass /*clazz*/) {
+  return (jboolean)fakeMethod();
+}
+
+static JNINativeMethod gMethods[] = {
+    {"nativeFakeMethod", "()Z",
+     (void *)com_android_tests_apex_app_nativeFakeMethod}};
+
+} // anonymous namespace
+
+int register_android_native_code_test_data(JNIEnv *env) {
+  jclass clazz = env->FindClass("com/android/tests/apex/app/ApkInApexTests");
+  return env->RegisterNatives(clazz, gMethods,
+                              sizeof(gMethods) / sizeof(JNINativeMethod));
+}
+
+jint JNI_OnLoad(JavaVM *vm, void * /*reserved*/) {
+  JNIEnv *env = nullptr;
+  if (vm->GetEnv((void **)&env, JNI_VERSION_1_6) != JNI_OK)
+    return JNI_ERR;
+  if (register_android_native_code_test_data(env))
+    return JNI_ERR;
+  return JNI_VERSION_1_6;
+}
diff --git a/tests/app/src/com/android/tests/apex/app/ApkInApexTests.java b/tests/app/src/com/android/tests/apex/app/ApkInApexTests.java
index e9d1920..f069378 100644
--- a/tests/app/src/com/android/tests/apex/app/ApkInApexTests.java
+++ b/tests/app/src/com/android/tests/apex/app/ApkInApexTests.java
@@ -79,4 +79,12 @@
         assertThat(pi.requestedPermissions).asList()
                 .contains("android.permission.START_ACTIVITIES_FROM_BACKGROUND");
     }
+
+    @Test
+    public void testJniCalls() throws Exception {
+        System.loadLibrary("ApkInApex_jni");
+        assertThat(nativeFakeMethod()).isTrue();
+    }
+
+    private native boolean nativeFakeMethod();
 }
diff --git a/tests/src/com/android/tests/apex/host/ApkInApexTests.java b/tests/src/com/android/tests/apex/host/ApkInApexTests.java
index 386a9da..8452e41 100644
--- a/tests/src/com/android/tests/apex/host/ApkInApexTests.java
+++ b/tests/src/com/android/tests/apex/host/ApkInApexTests.java
@@ -96,4 +96,9 @@
     public void testPrivPermissionIsGranted() throws Exception {
         runPhase("testPrivPermissionIsGranted");
     }
+
+    @Test
+    public void testJniCalls() throws Exception {
+        runPhase("testJniCalls");
+    }
 }