This test verifies PerfTestRunner.runPerSecond() outputs log as expected.

Running 5 times
Ignoring warm-up run (1 runs/s)
2 runs/s
4 runs/s
5 runs/s
8 runs/s
10 runs/s

Time:
values 2, 4, 5, 8, 10 runs/s
avg 5.8 runs/s
median 5 runs/s
stdev 3.19 runs/s
min 2 runs/s
max 10 runs/s