Formally remove children when the parent device is removed

Although the directory structure for children was being removed when
the parent device was removed, `remove_device()` was not actually being
called on for the children. This meant that (for example) uevents were
not being generated for children when the parent was removed which is
different behavior than on actual hardware.

src/umockdev.vala

@@ -637,13 +637,57 @@ public class Testbed: GLib.Object {
     public void remove_device (string syspath)
     {
         string real_path = Path.build_filename(this.root_dir, syspath);
-        string devname = Path.get_basename(syspath);
 
         if (!FileUtils.test(real_path, FileTest.IS_DIR)) {
             critical("umockdev_testbed_remove_device(): device %s does not exist", syspath);
             return;
         }
 
+        string path = Path.build_filename(real_path, "uevent");
+        if (!FileUtils.test(path, FileTest.IS_REGULAR)) {
+            critical("umockdev_testbed_remove_device(): device %s does not appear to be a device", syspath);
+            return;
+        }
+
+        remove_with_children(syspath);
+    }
+
+    private void remove_with_children (string syspath)
+    {
+        string real_path = Path.build_filename(this.root_dir, syspath);
+
+        try {
+            Dir dir = Dir.open(real_path);
+            string? name = null;
+            while (( name = dir.read_name( )) != null) {
+                string path = Path.build_filename(real_path, name);
+                // Skip over symlinks
+                if (FileUtils.test(path, FileTest.IS_SYMLINK)) {
+                    continue;
+                }
+
+                // Recurse into the directory and remove any children therein.
+                if (FileUtils.test(path, FileTest.IS_DIR)) {
+                    string child_syspath = Path.build_filename(syspath, name);
+                    remove_with_children(child_syspath);
+                }
+            }
+        } catch (FileError e) {
+            critical("umockdev_testbed_remove_device(): cannot determine children of %s: %s",
+                     syspath, e.message);
+        }
+
+        // See if this syspath actually corresponds to a device by seeing if
+        // there is a "uevent" file in the directory. If not, then there is
+        // no device to remove so the work is finished.
+        string path = Path.build_filename(real_path, "uevent");
+        if (!FileUtils.test(path, FileTest.IS_REGULAR)) {
+            return;
+        }
+
+        // This syspath corresponds to a device, so remove it.
+
+        string devname = Path.get_basename(syspath);
         string subsystem;
 
         try {

tests/test-umockdev.py

@@ -192,6 +192,59 @@ def on_uevent(client, action, device, counters):
         mainloop.run()
         self.assertEqual(counter, [0, 1, 0, syspath, None, '1'])
 
+    def test_remove_usb_parent_device(self):
+        '''testbed removing a USB parent device removes children'''
+
+        counter = {}
+
+        def on_uevent(client, action, device, counters):
+            key = device.get_sysfs_path()
+            counters.setdefault(key, [0, 0])
+            if action == 'add':
+                counters[key][0] += 1
+            elif action == 'remove':
+                counters[key][1] += 1
+
+        # set up listener for uevent signal
+        client = GUdev.Client.new(['usb'])
+        client.connect('uevent', on_uevent, counter)
+        mainloop = GLib.MainLoop()
+
+        parent_syspath = self.testbed.add_device('usb', 'myparentdev', None, ['idVendor', '0815'], ['ID_INPUT', '1'])
+        self.assertNotEqual(parent_syspath, None)
+
+        child1_syspath = self.testbed.add_device('usb', 'child1', parent_syspath, ['idVendor', '0815'], ['ID_INPUT', '1'])
+        self.assertNotEqual(child1_syspath, None)
+
+        child2_syspath = self.testbed.add_device('usb', 'child2', parent_syspath, ['idVendor', '0815'], ['ID_INPUT', '1'])
+        self.assertNotEqual(child2_syspath, None)
+
+        # Run the main loop for 0.5 seconds to catch the "add" uevent, which
+        # should be automatically generated by the call to `add_device()`.
+        GLib.timeout_add(500, mainloop.quit)
+        mainloop.run()
+        self.assertIn(parent_syspath, counter)
+        self.assertIn(child1_syspath, counter)
+        self.assertIn(child2_syspath, counter)
+        self.assertEqual(counter[parent_syspath], [1, 0])
+        self.assertEqual(counter[child1_syspath], [1, 0])
+        self.assertEqual(counter[child2_syspath], [1, 0])
+
+        # Just remove the parent, the children should also be removed.
+        self.testbed.remove_device(parent_syspath)
+
+        # Run the main loop for 0.5 seconds to catch the "remove" uevent, which
+        # should be automatically generated by the call to `remove_device()`.
+        GLib.timeout_add(500, mainloop.quit)
+        mainloop.run()
+        self.assertEqual(counter[parent_syspath], [1, 1])
+        self.assertEqual(counter[child1_syspath], [1, 1])
+        self.assertEqual(counter[child2_syspath], [1, 1])
+
+        # Verify that the parent syspath has been removed (and therefore the
+        # children syspaths have also been removed.)
+        self.assertFalse(os.path.exists(parent_syspath))
+
     def test_add_from_string(self):
         self.assertTrue(self.testbed.add_from_string('''P: /devices/dev1
 E: SIMPLE_PROP=1