Bug#12959 mysqltest crashes if testcase passed with -x option

client/mysqltest.c:
  Fixes for mysqltest -x  <filename>
mysql-test/t/mysqltest.test:
  Test mysqltest -x <filename>
mysql-test/include/mysqltest-x.inc:
  New BitKeeper file ``mysql-test/include/mysqltest-x.inc''

client/mysqltest.c

@@ -2169,8 +2169,10 @@ int read_line(char *buf, int size)
     if (feof(cur_file->file))
     {
   found_eof:
-      if (cur_file->file != stdin)
+      if (cur_file->file != stdin){
 	my_fclose(cur_file->file, MYF(0));
+        cur_file->file= 0;
+      }
       my_free((gptr)cur_file->file_name, MYF(MY_ALLOW_ZERO_PTR));
       cur_file->file_name= 0;
       lineno--;
@@ -2556,10 +2558,11 @@ get_one_option(int optid, const struct my_option *opt __attribute__((unused)),
 	argument= buff;
       }
       fn_format(buff, argument, "", "", 4);
-      DBUG_ASSERT(cur_file->file == 0);
+      DBUG_ASSERT(cur_file == file_stack && cur_file->file == 0);
       if (!(cur_file->file=
             my_fopen(buff, O_RDONLY | FILE_BINARY, MYF(MY_WME))))
-	die("Could not open %s: errno = %d", argument, errno);
+	die("Could not open %s: errno = %d", buff, errno);
+      cur_file->file_name= my_strdup(buff, MYF(MY_FAE));
       break;
     }
   case 'm':
@@ -3746,9 +3749,8 @@ int main(int argc, char **argv)
 			embedded_server_args,
 			(char**) embedded_server_groups))
     die("Can't initialize MySQL server");
-  if (cur_file == file_stack)
+  if (cur_file == file_stack && cur_file->file == 0)
   {
-    DBUG_ASSERT(cur_file->file == 0);
     cur_file->file= stdin;
     cur_file->file_name= my_strdup("<stdin>", MYF(MY_WME));
   }

mysql-test/include/mysqltest-x.inc

+echo Output from mysqltest-x.inc;
+

mysql-test/t/mysqltest.test

@@ -792,6 +792,19 @@ select "a" as col1, "c" as col2;
 --error 1
 --exec echo "save_master_pos; sync_with_master a;" | $MYSQL_TEST 2>&1
 
+
+# ----------------------------------------------------------------------------
+# Test mysqltest arguments
+# ----------------------------------------------------------------------------
+
+# -x <file_name>, use the file specified after -x as the test file
+--exec $MYSQL_TEST < $MYSQL_TEST_DIR/include/mysqltest-x.inc
+--exec $MYSQL_TEST -x $MYSQL_TEST_DIR/include/mysqltest-x.inc
+--exec $MYSQL_TEST --result_file=$MYSQL_TEST_DIR/include/mysqltest-x.inc
+--error 1
+--exec $MYSQL_TEST -x non_existing_file.inc
+
+
 # ----------------------------------------------------------------------------
 # TODO Test queries, especially their errormessages... so it's easy to debug 
 # new scripts and diagnose errors