diff --git a/src/tests/test_txn_close_open_commit.c b/src/tests/test_txn_close_open_commit.c
index 2036e8504c4432309de26f4af9d086c8fed7af4f..e1e257a53851e9d61d1a2d277a959f38444ba9a4 100644
--- a/src/tests/test_txn_close_open_commit.c
+++ b/src/tests/test_txn_close_open_commit.c
@@ -8,6 +8,9 @@
 #include <db.h>
 #include "test.h"
 
+// Recreate a mysqld crash by closing and opening a db within a transaction.
+// The crash occurs when writing a dirty cachetable pair, so we insert one
+// row.
 void test_txn_close_open_commit(void) {
 
 #ifndef USE_TDB