diff --git a/src/lib/io/bytebuffer.go b/src/lib/io/bytebuffer.go
index bc6a737..5d4cd8a 100644
--- a/src/lib/io/bytebuffer.go
+++ b/src/lib/io/bytebuffer.go
@@ -74,6 +74,13 @@
 	return n, nil
 }
 
+// WriteByte appends the byte c to the buffer.
+// Because Write never fails and WriteByte is not part of the
+// io.Writer interface, it does not need to return a value.
+func (b *ByteBuffer) WriteByte(c byte) {
+	b.Write([]byte{c});
+}
+
 // Read reads the next len(p) bytes from the buffer or until the buffer
 // is drained.  The return value n is the number of bytes read; err is always nil.
 func (b *ByteBuffer) Read(p []byte) (n int, err os.Error) {
diff --git a/src/lib/io/bytebuffer_test.go b/src/lib/io/bytebuffer_test.go
index e91a641..5a54322 100644
--- a/src/lib/io/bytebuffer_test.go
+++ b/src/lib/io/bytebuffer_test.go
@@ -101,20 +101,23 @@
 		}
 		check(t, "TestBasicOperations (4)", &buf, "a");
 
-		n, err = buf.Write(data[1 : 26]);
-		if n != 25 {
+		buf.WriteByte(data[1]);
+		check(t, "TestBasicOperations (5)", &buf, "ab");
+
+		n, err = buf.Write(data[2 : 26]);
+		if n != 24 {
 			t.Errorf("wrote 25 bytes, but n == %d\n", n);
 		}
-		check(t, "TestBasicOperations (5)", &buf, string(data[0 : 26]));
-
-		buf.Truncate(26);
 		check(t, "TestBasicOperations (6)", &buf, string(data[0 : 26]));
 
-		buf.Truncate(20);
-		check(t, "TestBasicOperations (7)", &buf, string(data[0 : 20]));
+		buf.Truncate(26);
+		check(t, "TestBasicOperations (7)", &buf, string(data[0 : 26]));
 
-		empty(t, "TestBasicOperations (8)", &buf, string(data[0 : 20]), make([]byte, 5));
-		empty(t, "TestBasicOperations (9)", &buf, "", make([]byte, 100));
+		buf.Truncate(20);
+		check(t, "TestBasicOperations (8)", &buf, string(data[0 : 20]));
+
+		empty(t, "TestBasicOperations (9)", &buf, string(data[0 : 20]), make([]byte, 5));
+		empty(t, "TestBasicOperations (10)", &buf, "", make([]byte, 100));
 	}
 }