Adding a manual test for cov that will eventually be added to CI

tests/manualtest_cov.py

@@ -0,0 +1,26 @@
+import BAC0
+from BAC0.core.devices.local.models import analog_value
+from bacpypes.primitivedata import Real
+import time
+
+device = BAC0.lite('192.168.211.55/24', deviceId=123)
+client = BAC0.lite('192.168.212.12/24')
+
+new_obj = analog_value()
+new_obj.add_objects_to_application(device)
+
+# From Server
+dev_av = device.this_application.get_object_name('AV')
+print(dev_av.covIncrement)
+
+# From client
+dev = dev = BAC0.device('192.168.211.55', 123, client, poll=0)
+av = dev['AV']
+dev['AV'].subscribe_cov(lifetime=0)
+
+print()
+while True:
+    print(dev['AV'])
+    time.sleep(1)
+    dev['AV'] += 1
+    time.sleep(1)