1 
2 --- test_minus_after_plus()
3 [0] same lines L2 R2 @L 0 @R 0
4 [1] minus lines L3 R0 @L 4 @R 10
5 [2] plus lines L0 R3 @L 4 @R 4
6 [3] same lines L2 R2 @L 10 @R 10
7 
8 --- test_plus_after_plus()
9 [0] same lines L2 R2 @L 0 @R 0
10 [1] minus lines L3 R0 @L 4 @R 4
11 [2] plus lines L0 R3 @L 10 @R 4
12 [3] same lines L2 R2 @L 10 @R 10