Test 1
- Create a room, draw something. Join the room from another client and see that image appears
Result: The image should appear in the joinee screen
Test 2
- Repeat 1 in above test
- Close the second client
Result: In the main client's screen, the other client should be left
Test 3
- Repeat 1 in Test 1
- Close the main client
Result: The main client is updated correctly
Test 4
- Create 2 sub clients
- Draw in one sub client and in main client
Result: All the screens are consistent