diff --git a/src/umockdev.vala b/src/umockdev.vala
index 8d1f5851..d04eabbd 100644
--- a/src/umockdev.vala
+++ b/src/umockdev.vala
@@ -87,6 +87,12 @@ public class Testbed: GLib.Object {
         this.sys_dir = Path.build_filename(this.root_dir, "sys");
         DirUtils.create(this.sys_dir, 0755);
 
+        /* Create "bus" and "class" directories to make libudev happy */
+        string bus_path = Path.build_filename(this.sys_dir, "bus");
+        DirUtils.create(bus_path, 0755);
+        string class_path = Path.build_filename(this.sys_dir, "class");
+        DirUtils.create(class_path, 0755);
+
         this.dev_fd = new HashTable<string, int> (str_hash, str_equal);
         this.dev_script_runner = new HashTable<string, ScriptRunner> (str_hash, str_equal);
         this.custom_handlers = new HashTable<string, IoctlBase> (str_hash, str_equal);
diff --git a/tests/test-umockdev-vala.vala b/tests/test-umockdev-vala.vala
index 2d29abc1..98b371f4 100644
--- a/tests/test-umockdev-vala.vala
+++ b/tests/test-umockdev-vala.vala
@@ -159,14 +159,14 @@ t_testbed_fs_ops ()
   assert_cmpstr (syspath, CompareOperator.EQ, "/sys/devices/dev1");
 
   // absolute paths
-  assert_listdir ("/sys", {"bus", "devices"});
+  assert_listdir ("/sys", {"bus", "class", "devices"});
   assert_listdir ("/sys/devices", {"dev1"});
   assert_listdir ("/sys/bus", {"pci"});
   assert_listdir ("/sys/devices/dev1", {"a", "subsystem", "uevent"});
 
   // change directory into trapped /sys
   assert_cmpint (Posix.chdir ("/sys"), CompareOperator.EQ, 0);
-  assert_listdir (".", {"bus", "devices"});
+  assert_listdir (".", {"bus", "class", "devices"});
   assert_listdir ("bus", {"pci"});
   assert_cmpstr (Environment.get_current_dir (), CompareOperator.EQ, "/sys");
 
@@ -174,9 +174,6 @@ t_testbed_fs_ops ()
   assert_listdir (".", {"a", "subsystem", "uevent"});
   assert_cmpstr (Environment.get_current_dir (), CompareOperator.EQ, "/sys/devices/dev1");
 
-  assert_cmpint (Posix.chdir ("/sys/class"), CompareOperator.EQ, -1);
-  assert_cmpint (Posix.errno, CompareOperator.EQ, Posix.ENOENT);
-
   // relative paths into trapped /sys; this only works if the real /sys exists, as otherwise realpath() fails in trap_path()
   if (!have_real_sys) {
       stdout.printf ("[SKIP relative paths: environment has no real /sys]\n");
@@ -184,12 +181,12 @@ t_testbed_fs_ops ()
   }
 
   assert_cmpint (Posix.chdir ("/"), CompareOperator.EQ, 0);
-  assert_listdir ("sys", {"bus", "devices"});
+  assert_listdir ("sys", {"bus", "class", "devices"});
   assert_listdir ("sys/devices", {"dev1"});
   assert_listdir ("sys/bus", {"pci"});
 
   assert_cmpint (Posix.chdir ("/etc"), CompareOperator.EQ, 0);
-  assert_listdir ("../sys", {"bus", "devices"});
+  assert_listdir ("../sys", {"bus", "class", "devices"});
   assert_listdir ("../sys/devices", {"dev1"});
   assert_listdir ("../sys/bus", {"pci"});
 
diff --git a/tests/test-umockdev.c b/tests/test-umockdev.c
index 8b319495..90f5f47f 100644
--- a/tests/test-umockdev.c
+++ b/tests/test-umockdev.c
@@ -107,20 +107,30 @@ t_testbed_read_buf_delay(ulong delay, int fd, char* buf, ssize_t length)
 static guint
 num_udev_devices(void)
 {
-    GUdevEnumerator *enumerator;
-    GList *result;
-    guint num;
-
-    g_autoptr (GUdevClient) client = g_udev_client_new(NULL);
-    g_assert(client);
+    struct udev *udev;
+    struct udev_enumerate *enumerate;
+    struct udev_list_entry *entry;
+    int err;
+    guint num = 0;
 
-    enumerator = g_udev_enumerator_new(client);
-    g_assert(enumerator);
-    result = g_udev_enumerator_execute(enumerator);
-    num = g_list_length(result);
+    udev = udev_new();
+    g_assert(udev);
+
+    enumerate = udev_enumerate_new(udev);
+    g_assert(enumerate);
+    
+    // NB: using libudev here instead of GUdev so that we can check the return
+    // value of udev_enumerate_scan_devices().
+    // https://github.com/martinpitt/umockdev/issues/144
+    err = udev_enumerate_scan_devices(enumerate);
+    g_assert_cmpint(err, >=, 0);
+
+    udev_list_entry_foreach(entry, udev_enumerate_get_list_entry(enumerate)) {
+        num++;
+    }
 
-    g_list_free_full(result, g_object_unref);
-    g_object_unref(enumerator);
+    udev_enumerate_unref(enumerate);
+    udev_unref(udev);
 
     return num;
 }