diff --git a/mysql-test/r/date_formats.result b/mysql-test/r/date_formats.result
index f8189266e50..39e3aa0ca8e 100644
--- a/mysql-test/r/date_formats.result
+++ b/mysql-test/r/date_formats.result
@@ -503,3 +503,12 @@ d1	d2
 02	February
 01	January
 drop table t1;
+select str_to_date( 1, NULL );
+str_to_date( 1, NULL )
+NULL
+select str_to_date( NULL, 1 );
+str_to_date( NULL, 1 )
+NULL
+select str_to_date( 1, IF(1=1,NULL,NULL) );
+str_to_date( 1, IF(1=1,NULL,NULL) )
+NULL
diff --git a/mysql-test/t/date_formats.test b/mysql-test/t/date_formats.test
index c007c2f5205..b4c6cf0d72a 100644
--- a/mysql-test/t/date_formats.test
+++ b/mysql-test/t/date_formats.test
@@ -269,4 +269,11 @@ insert into t1 (f1) values ("2005-01-01");
 insert into t1 (f1) values ("2005-02-01");
 select date_format(f1, "%m") as d1, date_format(f1, "%M") as d2 from t1 order by date_format(f1, "%M");
 drop table t1;
+
+#
+# Bug #15828
+#
+select str_to_date( 1, NULL );
+select str_to_date( NULL, 1 );
+select str_to_date( 1, IF(1=1,NULL,NULL) );
 # End of 4.1 tests