test-umount: add a simple test for swap_list_get()

The implementation seems buggy:
/* test_swap_list("/home/zbyszek/src/systemd/test/test-umount/example.swaps") */
path=0 o= f=0x0 try-ro=no dev=0:0
path=/some/swapfile2 o= f=0x0 try-ro=no dev=0:0
path=/some/swapfile o= f=0x0 try-ro=no dev=0:0
path=/dev/dm-2 o= f=0x0 try-ro=no dev=0:0

1 files changed, 21 insertions, 0 deletions

diff --git a/src/test/test-umount.c b/src/test/test-umount.c
index dfafc71acf..e1d56291ac 100644
--- a/src/test/test-umount.c
+++ b/src/test/test-umount.c
@@ -24,6 +24,24 @@ static void test_mount_points_list(const char *fname) {
                           major(m->devnum), minor(m->devnum));
 }
 
+static void test_swap_list(const char *fname) {
+        _cleanup_(mount_points_list_free) LIST_HEAD(MountPoint, mp_list_head);
+        MountPoint *m;
+
+        log_info("/* %s(\"%s\") */", __func__, fname ?: "/proc/self/mountinfo");
+
+        LIST_HEAD_INIT(mp_list_head);
+        assert_se(swap_list_get(fname, &mp_list_head) >= 0);
+
+        LIST_FOREACH(mount_point, m, mp_list_head)
+                log_debug("path=%s o=%s f=0x%lx try-ro=%s dev=%u:%u",
+                          m->path,
+                          strempty(m->remount_options),
+                          m->remount_flags,
+                          yes_no(m->try_remount_ro),
+                          major(m->devnum), minor(m->devnum));
+}
+
 int main(int argc, char **argv) {
         log_set_max_level(LOG_DEBUG);
         log_parse_environment();
@@ -33,4 +51,7 @@ int main(int argc, char **argv) {
         test_mount_points_list(get_testdata_dir("/test-umount/empty.mountinfo"));
         test_mount_points_list(get_testdata_dir("/test-umount/garbled.mountinfo"));
         test_mount_points_list(get_testdata_dir("/test-umount/rhbug-1554943.mountinfo"));
+
+        test_swap_list(NULL);
+        test_swap_list(get_testdata_dir("/test-umount/example.swaps"));
 }