diff --git a/Android.bp b/Android.bp
index ac8ca69..95756f5 100644
--- a/Android.bp
+++ b/Android.bp
@@ -27,4 +27,8 @@
         "//apex_available:platform",
         "com.android.bluetooth",
     ],
+
+    libs: [
+        "framework-annotations-lib",
+    ]
 }
diff --git a/java/com/android/vcard/JapaneseUtils.java b/java/com/android/vcard/JapaneseUtils.java
index 5b44944..7079648 100644
--- a/java/com/android/vcard/JapaneseUtils.java
+++ b/java/com/android/vcard/JapaneseUtils.java
@@ -16,6 +16,8 @@
 
 package com.android.vcard;
 
+import com.android.internal.annotations.VisibleForTesting;
+
 import java.util.HashMap;
 import java.util.Map;
 
@@ -23,7 +25,8 @@
  * TextUtils especially for Japanese.
  */
 /* package */ class JapaneseUtils {
-    static private final Map<Character, String> sHalfWidthMap =
+    @VisibleForTesting
+    static final Map<Character, String> sHalfWidthMap =
         new HashMap<Character, String>();
 
     static {
diff --git a/tests/src/com/android/vcard/tests/JapaneseUtilsTest.java b/tests/src/com/android/vcard/tests/JapaneseUtilsTest.java
new file mode 100644
index 0000000..452944e
--- /dev/null
+++ b/tests/src/com/android/vcard/tests/JapaneseUtilsTest.java
@@ -0,0 +1,31 @@
+/*
+ * 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.
+ */
+
+package com.android.vcard;
+
+import com.android.vcard.JapaneseUtils;
+
+import junit.framework.TestCase;
+
+public class JapaneseUtilsTest extends TestCase {
+    static final char TEST_CONTAINED_CHAR = '\uFFE5';
+    static final char TEST_UNCONTAINED_CHAR = '\uFFF5';
+
+    public void testTryGetHalfWidthText() {
+        assertNull(JapaneseUtils.tryGetHalfWidthText(TEST_UNCONTAINED_CHAR));
+        assertEquals(JapaneseUtils.tryGetHalfWidthText(TEST_CONTAINED_CHAR), "\u005C\u005C");
+    }
+}