tests: Ensure objects are free'ed at the end of tests

The objects may not be garbage collected otherwise.

tests/capture.py

@@ -17,6 +17,7 @@ c.enumerate()
 devices = c.get_devices()
 
 d = devices[0]
+del devices
 
 d.open_sync()
 
@@ -24,6 +25,9 @@ img = d.capture_sync(True)
 
 d.close_sync()
 
+del d
+del c
+
 width = img.get_width()
 height = img.get_height()
 

tests/synaptics/custom.py

@@ -11,6 +11,7 @@ c.enumerate()
 devices = c.get_devices()
 
 d = devices[0]
+del devices
 
 assert d.get_driver() == "synaptics"
 
@@ -40,3 +41,6 @@ print("deleting")
 d.delete_print_sync(p)
 print("delete done")
 d.close_sync()
+
+del d
+del c

tests/virtual-image.py

@@ -83,6 +83,8 @@ class VirtualImage(unittest.TestCase):
     @classmethod
     def tearDownClass(cls):
         shutil.rmtree(cls.tmpdir)
+        del cls.dev
+        del cls.ctx
 
     def setUp(self):
         self.dev.open_sync()