diff --git a/libnativebridge/tests/Android.mk b/libnativebridge/tests/Android.mk
index b3861e0..5b9ba1c 100644
--- a/libnativebridge/tests/Android.mk
+++ b/libnativebridge/tests/Android.mk
@@ -33,10 +33,15 @@
     libnativebridge \
     libnativebridge-dummy
 
+libnativebridge_tests_common_cflags := \
+    -Wall \
+    -Werror \
+
 $(foreach file,$(test_src_files), \
     $(eval include $(CLEAR_VARS)) \
     $(eval LOCAL_SHARED_LIBRARIES := $(shared_libraries)) \
     $(eval LOCAL_SRC_FILES := $(file)) \
+    $(eval LOCAL_CFLAGS := $(libnativebridge_tests_common_cflags)) \
     $(eval LOCAL_MODULE := $(notdir $(file:%.cpp=%))) \
     $(eval include $(BUILD_NATIVE_TEST)) \
 )
@@ -45,6 +50,7 @@
     $(eval include $(CLEAR_VARS)) \
     $(eval LOCAL_SHARED_LIBRARIES := $(shared_libraries)) \
     $(eval LOCAL_SRC_FILES := $(file)) \
+    $(eval LOCAL_CFLAGS := $(libnativebridge_tests_common_cflags)) \
     $(eval LOCAL_MODULE := $(notdir $(file:%.cpp=%))) \
     $(eval include $(BUILD_HOST_NATIVE_TEST)) \
 )
diff --git a/libnativebridge/tests/PreInitializeNativeBridge_test.cpp b/libnativebridge/tests/PreInitializeNativeBridge_test.cpp
index f3e5f38..cd5a8e2 100644
--- a/libnativebridge/tests/PreInitializeNativeBridge_test.cpp
+++ b/libnativebridge/tests/PreInitializeNativeBridge_test.cpp
@@ -30,12 +30,12 @@
 
 namespace android {
 
-static constexpr const char* kTestData = "PreInitializeNativeBridge test.";
-
 TEST_F(NativeBridgeTest, PreInitializeNativeBridge) {
     ASSERT_TRUE(LoadNativeBridge(kNativeBridgeLibrary, nullptr));
 #if !defined(__APPLE__)         // Mac OS does not support bind-mount.
 #if !defined(__ANDROID__)       // Cannot write into the hard-wired location.
+    static constexpr const char* kTestData = "PreInitializeNativeBridge test.";
+
     // Try to create our mount namespace.
     if (unshare(CLONE_NEWNS) != -1) {
         // Create a dummy file.