Bluepill is a reliable iOS testing tool that runs UI tests using multiple simulators on a single machine
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Latest commit 6faa025 Oct 10, 2017 @bayareabear bayareabear add 'sample' command to show the call stack when timeout due to app h… (

* add 'sample' command to show the call stack when timeout due to app hangs

* saving 'sample' command log to /tmp/ folder

* change log directory and update log file name


Build Status:

Bluepill is a tool to run iOS tests in parallel using multiple simulators.


LinkedIn created Bluepill to run its large iOS test suite in a reasonable amount of time. If you want the long story, read the blog post.


  • Running tests in parallel by using multiple simulators.
  • Automatically packing tests into groups.
  • Running tests in headless mode to reduce memory consumption.
  • Generating a junit report after each test run.
  • Reporting test running stats, including test running speed and environment robustness.
  • Retrying when the Simulator hangs or crashes.


It is quick and easy to start using Bluepill!

  • Get bluepill binary: build from source or use our releases. You can also get the binary from Homebrew.
$ brew install bluepill
  • Build your app and test bundle. You must build-for-testing if you use xcodebuild in terminal.
  • Run bluepill using the .xctestrun file generated by Xcode.
$ bluepill --xctestrun-path ./SampleAppTest_iphonesimulator10.3-x86_64.xctestrun -o ./output/

Alternatively, you can use a configuration file like the one below:

   "xctestrun-path": "./SampleAppTest_iphonesimulator10.3-x86_64.xctestrun", # Relative path or abs path
   "output-dir": "./build/" # Relative path or abs path

And run

$ bluepill -c config.json


A full list supported options are listed here.

Config Arguments Command Line Arguments Explanation Required Default value
app -a The path to the host application to execute (your .app) N n/a
xctestrun-path The path to the .xctestrun file that xcode leaves when you build-for-testing. Y n/a
output-dir -o Directory where to put output log files (bluepill only) Y n/a
config -c Read options from the specified configuration file instead of the command line N n/a
device -d On which device to run the app. N iPhone 6
exclude -x Exclude a testcase in the set of tests to run (takes priority over include). N empty
headless -H Run in headless mode (no GUI). N off
xcode-path -X Path to xcode. N xcode-select -p
include -i Include a testcase in the set of tests to run (unless specified in exclude). N all tests
json-output -J Print test timing information in JSON format. N off
junit-output -j Print results in JUnit format. N true
list-tests -l Only list tests in bundle N false
num-sims -n Number of simulators to run in parallel. (bluepill only) N 4
plain-output -p Print results in plain text. N true
printf-config -P Print a configuration file suitable for passing back using the -c option. N n/a
error-retries -R Number of times to recover from simulator/app crashing/hanging and continue running N 5
failure-tolerance -f Number of times to retry on test failures N 0
only-retry-failed -F When failure-tolerance > 0, only retry tests that failed N false
runtime -r What runtime to use. N iOS 10.3
stuck-timeout -S Timeout in seconds for a test that seems stuck (no output). N 300s
test-timeout -T Timeout in seconds for a test that is producing output. N 300s
test-bundle-path -t The path to the test bundle to execute (single .xctest). N n/a
additional-unit-xctests n/a Additional XCTest bundles that is not Plugin folder N n/a
additional-ui-xctests n/a Additional XCTUITest bundles that is not Plugin folder N n/a
repeat-count -C Number of times we'll run the entire test suite (used for load testing). N 1
no-split -N Test bundles you don't want to be packed into different groups to run in parallel. N n/a
quiet -q Turn off all output except fatal errors. N YES
reuse-simulator n/a Enable reusing simulators between test bundles N NO
diagnostics n/a Enable collection of diagnostics in outputDir in case of test failures N NO
help -h Help. N n/a
runner-app-path -u The test runner for UI tests. N n/a
screenshots-directory n/a Directory where simulator screenshots for failed ui tests will be stored N n/a




Bluepill only works with Xcode 9.0. If you're looking for Xcode 8 support, please check out the xcode8 branch.


Bluepill was inspired by parallel iOS test and Facebook’s xctool and FBSimulatorControl. The Bluepill icon was created by Maria Iu.

Q & A

  • Are we able to run Xcode UI Testing bundle with Bluepill

    YES, we recently added support for Xcode UI Testing bundles. Thanks to the inspiration from FBSimulatorControl. Bluepill now supports Xcode unit test bundle and UI test bundles.

  • Easiest way to get Bluepill binary?

    Latest release.

  • How to test Bluepill in Xcode

    Select BPSampleApp scheme and build it first. Then you can switch back to bluepill or bluepill-cli scheme to run their tests.

  • How to get Bluepill binary from source?

    Run ./ build to test and build Bluepill. The binary will be output in the ./build folder.

  • How to test my changes to Bluepill?

    Run ./scripts/ test.

  • How to BUMP the max files and max procs to support running multiple simulators on macOS?

    Check -