Fix test bundling on physical iOS devices

[bartekpacia]

This PR fixes #1297.

Caveats

• Running tests on iOS works only in release mode (patrol test --release).

• Hot Restart doesn't work.
  That's because, in a Flutter app built in release mode, there's no Dart VM that can JIT compile code.
  In other words, for Hot Restart to work, the app must be started in debug mode on iOS.
  Starting the app in debug mode on iOS is mutually exclusive with test bundling.

  A workaround would be to not use test bundling at all when using Hot Restart.
  This would require re-adding the code that was present before test bundling.

  But even if we fixed this and re-added that, Hot Restart on iOS wouldn't work right away. We'd also have to fix Hot restart on physical iOS is not working #1059.

• Enabling or disabling airplane mode crashes the test suite.

cc: @mateuszwojtczak, @jBorkowska

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[bartekpacia]

Tested locally on my private iPhone and iPad and it works. Here's the xcresult:

[bartekpacia]

Note:

Calling XCUIApplication.launch() with the debugger attached causes really nasty crashes.

[bartekpacia]

TODO:

Print error message when trying to patrol test on physical iOS device.

For example:

Running tests on a physical iOS devices requires the --release flag.

[bartekpacia]

A workaround would be to not use test bundling at all when using Hot Restart.
This would require re-adding the code that was present before test bundling.

Actually, we're already doing this.

But still, the Flutter bug breaks Hot Restart on physical iOS devices.

[shilangyu]

Are these limitations documented anywhere (do you have any changelog?)?

* Running tests on iOS works only in release mode (`patrol test --release`).

What is the predicted impact of this limitation? Is there any benefit of debug mode testing?

* Enabling or disabling airplane mode crashes the test suite.

Because of some connection issue?

[mateuszwojtczak]

LGTM! Do we plan using go-ios?

[bartekpacia]

Do we plan using go-ios?

go-ios is a replacement for ios-deploy. And since in this PR I've removed our usage of ios-deploy, using go-ios doesn't make much sense anymore.

[bartekpacia]

@shilangyu

Are these limitations documented anywhere (do you have any changelog?)?

Yes, we do, although it's pretty basic (https://pub.dev/packages/patrol/changelog).

We'll be rewriting the docs for 2.0 + writing a migration guide.

What is the predicted impact of this limitation? Is there any benefit of debug mode testing?

• no debugging on physical iOS devices, including:
  • no asserts in Dart
  • flutter logs doesn't work
• longer builds

We're aware of this.

Enabling or disabling airplane mode crashes the test suite.

Because of some connection issue?

I don't know, but I suspect it's because Patrol (running in the app under test) makes HTTP requests to the Patrol server (running in the instrumentation app). More specifically, all communication between these 2 apps happen over gRPC (which builds on HTTP/2’s long-lived connections).

And toggling (yes, toggling - everything works when airplane mode is enabled, and disabling it results in tests crashing) airplane mode probably somehow interferes with this.