Merge pull request #411 from smusuvat/test_parallelism

Test parallelism
Merge pull request #412 from smusuvat/test_parallelism

add back fixture defs removed by mistake
Merge remote-tracking branch 'upstream/test_parallelism' into test_parallelism
Merge pull request #413 from smusuvat/test_parallelism

Test parallelism
Merge remote-tracking branch 'upstream/test_parallelism' into test_parallelism
fix function call reference
add more tests