mobile: Add initial unit tests for jni_utility.(h|cc) (envoyproxy#30849)

This PR sets up an initial infrastructure for writing unit tests for
`jni_utility.(h|cc)`.

Signed-off-by: Fredy Wijaya <[email protected]>

mobile/library/common/jni/jni_utility.cc

@@ -1,7 +1,7 @@
 #include "library/common/jni/jni_utility.h"
 
-#include <stdlib.h>
-#include <string.h>
+#include <cstdlib>
+#include <cstring>
 
 #include "source/common/common/assert.h"
 
@@ -355,6 +355,15 @@ void javaByteArrayToProto(JniHelper& jni_helper, jbyteArray source,
   RELEASE_ASSERT(success, "Failed to parse protobuf message.");
 }
 
+LocalRefUniquePtr<jbyteArray> protoToJavaByteArray(JniHelper& jni_helper,
+                                                   const Envoy::Protobuf::MessageLite& source) {
+  size_t size = source.ByteSizeLong();
+  LocalRefUniquePtr<jbyteArray> byte_array = jni_helper.newByteArray(size);
+  auto bytes = jni_helper.getByteArrayElements(byte_array.get(), nullptr);
+  source.SerializeToArray(bytes.get(), size);
+  return byte_array;
+}
+
 std::string javaStringToString(JniHelper& jni_helper, jstring java_string) {
   if (!java_string) {
     return "";

mobile/library/common/jni/jni_utility.h

@@ -124,6 +124,10 @@ void javaByteArrayToString(JniHelper& jni_helper, jbyteArray jbytes, std::string
 void javaByteArrayToProto(JniHelper& jni_helper, jbyteArray source,
                           Envoy::Protobuf::MessageLite* dest);
 
+/** Converts from Proto to Java byte array. */
+LocalRefUniquePtr<jbyteArray> protoToJavaByteArray(JniHelper& jni_helper,
+                                                   const Envoy::Protobuf::MessageLite& source);
+
 /** Converts from Java `String` to C++ string. */
 std::string javaStringToString(JniHelper& jni_helper, jstring java_string);
 

mobile/test/common/jni/BUILD

@@ -103,3 +103,23 @@ cc_binary(
         ":jni_helper_test_lib",
     ],
 )
+
+cc_library(
+    name = "jni_utility_test_lib",
+    srcs = [
+        "jni_utility_test.cc",
+    ],
+    deps = [
+        "//library/common/jni:jni_utility_lib",
+    ],
+    alwayslink = True,
+)
+
+cc_binary(
+    name = "libenvoy_jni_utility_test.so",
+    testonly = True,
+    linkshared = True,
+    deps = [
+        ":jni_utility_test_lib",
+    ],
+)

mobile/test/common/jni/jni_utility_test.cc

@@ -0,0 +1,17 @@
+#include <jni.h>
+
+#include "library/common/jni/jni_utility.h"
+
+// NOLINT(namespace-envoy)
+
+// This file contains JNI implementation used by
+// `test/java/io/envoyproxy/envoymobile/jni/JniUtilityTest.java` unit tests.
+
+extern "C" JNIEXPORT jbyteArray JNICALL
+Java_io_envoyproxy_envoymobile_jni_JniUtilityTest_protoJavaByteArrayConversion(JNIEnv* env, jclass,
+                                                                               jbyteArray source) {
+  Envoy::JNI::JniHelper jni_helper(env);
+  Envoy::ProtobufWkt::Struct s;
+  Envoy::JNI::javaByteArrayToProto(jni_helper, source, &s);
+  return Envoy::JNI::protoToJavaByteArray(jni_helper, s).release();
+}

mobile/test/java/io/envoyproxy/envoymobile/jni/BUILD

@@ -10,3 +10,17 @@ envoy_mobile_android_test(
     ],
     native_lib_name = "envoy_jni_helper_test",
 )
+
+envoy_mobile_android_test(
+    name = "jni_utility_test",
+    srcs = [
+        "JniUtilityTest.java",
+    ],
+    native_deps = [
+        "//test/common/jni:libenvoy_jni_utility_test.so",
+    ],
+    native_lib_name = "envoy_jni_utility_test",
+    deps = [
+        "@maven//:com_google_protobuf_protobuf_javalite",
+    ],
+)

mobile/test/java/io/envoyproxy/envoymobile/jni/JniUtilityTest.java

@@ -0,0 +1,31 @@
+package io.envoyproxy.envoymobile.jni;
+
+import static org.assertj.core.api.Assertions.assertThat;
+
+import com.google.protobuf.Struct;
+import com.google.protobuf.Value;
+import org.junit.Test;
+import org.junit.runner.RunWith;
+import org.robolectric.RobolectricTestRunner;
+
+@RunWith(RobolectricTestRunner.class)
+public class JniUtilityTest {
+  public JniUtilityTest() { System.loadLibrary("envoy_jni_utility_test"); }
+
+  //================================================================================
+  // Native methods for testing.
+  //================================================================================
+  public static native byte[] protoJavaByteArrayConversion(byte[] source);
+
+  @Test
+  public void testProtoJavaByteArrayConversion() throws Exception {
+    Struct source =
+        Struct.newBuilder()
+            .putFields("string_key", Value.newBuilder().setStringValue("string_value").build())
+            .putFields("num_key", Value.newBuilder().setNumberValue(123).build())
+            .putFields("bool_key", Value.newBuilder().setBoolValue(true).build())
+            .build();
+    Struct dest = Struct.parseFrom(protoJavaByteArrayConversion(source.toByteArray()));
+    assertThat(source).isEqualTo(dest);
+  }
+}