Add support for multiple full paths on macos

[natebosch]

We cannot look up multiple basename commands in the system path and the
current macOsExecutable configuration may have existing uses in
dart_test.yaml files so it isn't safe to require full paths. Add a
separate macOsAbsolutePaths configuration to enable internal
definitions that check multiple full paths and execute the first one
that exists.

Add the basename firefox as a fallback. Adding that command to the
path is one workaround for users with firefox installed in an unexpected
location. This is also the only approach that is compatible with mac on
GitHub actions using the setup-firefox action.

There is no support here for dart_test.yaml. Users that are
configuring an executable for macOS will continue to have support for
only a single value, even if they are specifying an absolute path.

Tests remain skipped because our mono repo setup does not have a way to
include the setup-firefox action.

[github-actions]

PR Health

Changelog Entry ✔️

Package	Changed Files

Changes to files need to be accounted for in their respective changelogs.

Package publish validation ✔️

Package	Version	Status
package:checks	0.3.1-wip	WIP (no publish necessary)
package:test	1.25.9-wip	WIP (no publish necessary)
package:test_api	0.7.4-wip	WIP (no publish necessary)
package:test_core	0.6.6-wip	WIP (no publish necessary)

Documentation at https://github.com/dart-lang/ecosystem/wiki/Publishing-automation.

[natebosch]

This is the least invasive way I could see to make this change. I'm not sure if it's worth landing, but opening the PR for discussion.

[natebosch]

I think if we wanted we could support this in dart_test.yaml. We could accept either a single string, or a list of strings, and we could validate when parsing that only full paths are used if it is a list. We already have some inconsistency between the meaning of the arguments across OSes, so I don't think it's a particular problem to add this option/caveat exclusive to macOS.

[natebosch]

This fixes the problem for me on a local mac. It looks like maybe firefox doesn't come by default on github actions macos runs? I don't think mono package supports adding a firefox setup step. Any suggestions on a workaround @kevmoo ?

[natebosch]

It looks like maybe firefox doesn't come by default on github actions macos runs?

No, it still fails even if I manually add the setup-firefox steps.

[natebosch]

I cannot figure out the mac problem. Landing this is still worth it because it does fix things for me locally. @jakemac53 any concerns about landing this without unskipping the tests on CI, or with using the basename as a fallback?

[jakemac53]

I cannot figure out the mac problem. Landing this is still worth it because it does fix things for me locally. @jakemac53 any concerns about landing this without unskipping the tests on CI, or with using the basename as a fallback?

I am fine with it, we don't have a lot of people asking about this, so it isn't worth dumping a ton of time into. If people do get broken again they will file issues (plus, there is a workaround to set your own path).