xctool is drop-in replacement for xcodebuild test that adds a few extra features: Faster, parallelized test runs. xctool can optionally run all of your test bundles in parallel, speeding up your test runs significantly. At Facebook, we've seen 2x and 3x speed ups by parallelizing our runs. Use the -parallelize option with run-tests or test to enable. See Parallelizing Test Runs for more info. Stru