[Docs] Add more info about running tests on iOS

[bartekpacia]

I wish this info was there, that'd save me from looking inside the script.

Pre-launch Checklist

• I read the [Contributor Guide] and followed the process outlined there for submitting PRs.
• I read the [Tree Hygiene] wiki page, which explains my responsibilities.
• I read and followed the [Flutter Style Guide] and the [C++, Objective-C, Java style guides].
• I listed at least one issue that this PR fixes in the description above.
• I added new tests to check the change I am making or feature I am adding, or the PR is [test-exempt]. See [testing the engine] for instructions on writing and running engine tests.
• I updated/added relevant documentation (doc comments with ///).
• I signed the [CLA].
• All existing and new tests are passing.

[chinmaygarde]

cc @jmagman

[jmagman]

Shouldn't this be --ios-variant?

Suggested change

	--variant=host_debug_unopt_arm64 \
	--ios=ios_debug_sim_unopt_arm64
	--ios-variant ios_debug_sim_unopt_arm64

[bartekpacia]

That's right! But there's no difference in behavior between:

./flutter/testing/run_tests.py \
  --type=objc \
  --variant=host_debug_unopt_arm64 \
  --ios=ios_debug_sim_unopt_arm64

and

$ ./flutter/testing/run_tests.py \
  --type=objc \
  --variant=host_debug_unopt_arm64 \
  --ios-variant=ios_debug_sim_unopt_arm64

Apparently Python's argparser sees that the only option that starts with ios is ios-variant and it all goes well thanks to this.

Anyway thanks for the suggestion, fixed.

[jmagman]

We set FLUTTER_TEST_OUTPUTS_DIR env in our CI system, however if it's useful to be used on the command line parser.add_argument output option around here

engine/testing/run_tests.py

Line 1219 in 9b716e0

parser.add_argument(

And use that and fallback to FLUTTER_TEST_OUTPUTS_DIR is currently used, first if it's not passed in.

engine/testing/run_tests.py

Line 831 in 9b716e0

luci_test_outputs_path = os.environ.get('FLUTTER_TEST_OUTPUTS_DIR')

engine/testing/run_tests.py

Line 297 in 9b716e0

luci_test_outputs_path = os.environ.get('FLUTTER_TEST_OUTPUTS_DIR')

However if you don't want to touch the python code I understand. 🙂

[bartekpacia]

For now I'd prefer to leave it as it is (I'm low on time), but I might come back to it in the future and add a proper argument for that.

[jmagman]

LGTM

[jmagman]

@vashworth can you give it a second review?

[vashworth]

LGTM! Thanks for adding this!

[bartekpacia]

Thanks!