diff --git a/tests/gsm0408/gsm0408_test.c b/tests/gsm0408/gsm0408_test.c
index b5f8061..db1d45a 100644
--- a/tests/gsm0408/gsm0408_test.c
+++ b/tests/gsm0408/gsm0408_test.c
@@ -727,6 +727,17 @@
 		.dec_ascii = "(none)",
 		.dec_rc = -EIO,
 	},
+	{
+		.test_name = "decoding buffer is one byte too small (OS#4049)",
+
+		/* Decoding test */
+		.dec_hex   = "022143", /* "1234" */
+		.dec_ascii = "123",    /* '4' was truncated */
+		.dec_rc    = -ENOSPC,
+
+		/* Buffer length limitations */
+		.dec_buf_lim = 4,
+	},
 };
 
 static void test_bcd_number_encode_decode()
diff --git a/tests/gsm0408/gsm0408_test.ok b/tests/gsm0408/gsm0408_test.ok
index 844c201..d343869 100644
--- a/tests/gsm0408/gsm0408_test.ok
+++ b/tests/gsm0408/gsm0408_test.ok
@@ -186,6 +186,10 @@
   - Decoding HEX (buffer limit=0) ''...
     - Expected: (rc=-5) '(none)'
     -   Actual: (rc=-5) '(none)'
+- Running test: decoding buffer is one byte too small (OS#4049)
+  - Decoding HEX (buffer limit=4) '022143'...
+    - Expected: (rc=-28) '123'
+    -   Actual: (rc=-28) '123'
 
 Constructed RA:
 077-121-666-5