1 files changed, 18 insertions, 0 deletions
diff --git a/java/src/test/java/com/google/protobuf/AbstractMessageTest.java b/java/src/test/java/com/google/protobuf/AbstractMessageTest.java
index 3d05cb7d..fcbf019d 100644
--- a/java/src/test/java/com/google/protobuf/AbstractMessageTest.java
+++ b/java/src/test/java/com/google/protobuf/AbstractMessageTest.java
@@ -506,4 +506,22 @@ public class AbstractMessageTest extends TestCase {
         String.format("%s should have a different hash code from %s", m1, m2),
         m1.hashCode() == m2.hashCode());
   }
+
+  public void testCheckByteStringIsUtf8OnUtf8() {
+    ByteString byteString = ByteString.copyFromUtf8("some text");
+    AbstractMessageLite.checkByteStringIsUtf8(byteString);
+    // No exception thrown.
+  }
+
+  public void testCheckByteStringIsUtf8OnNonUtf8() {
+    ByteString byteString =
+        ByteString.copyFrom(new byte[]{(byte) 0x80}); // A lone continuation byte.
+    try {
+      AbstractMessageLite.checkByteStringIsUtf8(byteString);
+      fail("Expected AbstractMessageLite.checkByteStringIsUtf8 to throw IllegalArgumentException");
+    } catch (IllegalArgumentException exception) {
+      assertEquals("Byte string is not UTF-8.", exception.getMessage());
+    }
+  }
+
 }