The purpose of this PR is to make running all unit tests on Windows pass (vs failing a large portion of the tests as currently happens). This does not mean that the commands actually work when run on Windows, or that Windows support is tested, only that it's possible to actually run the tests themselves. This is prep for actually supporting parts of the tool on Windows in future PRs.
Major changes:
- Make the tests significantly more hermetic:
- Make almost all tools take a `Platform` constructor argument that can be used to inject a mock platform to control what OS the command acts like it is running on under test.
- Add a path `Context` object to the base command, whose style matches the `Platform`, and use that almost everywhere instead of the top-level `path` functions.
- In cases where Posix behavior is always required (such as parsing `git` output), explicitly use the `posix` context object for `path` functions.
- Start laying the groundwork for actual Windows support:
- Replace all uses of `flutter` as a command with a getter that returns `flutter` or `flutter.bat` as appropriate.
- For user messages that include relative paths, use a helper that always uses Posix-style relative paths for consistent output.
This bumps the version since quite a few changes have built up, and having a cut point before starting to make more changes to the commands to support Windows seems like a good idea.
Part of https://github.com/flutter/flutter/issues/86113
Most of the tool operates on packages in general, and the targetting
done currently by the `--plugins` flag is not actually restricted to
plugins, so this makes the name less confusing.
Part of https://github.com/flutter/flutter/issues/83413
- Updates the remaining tests (other than one that still needs to be
converted to the new base command, which will be fixed then) that
aren't using runCapturingPrint to do so to reduce test log spam.
- Simplifies and standardizes the matcher used for ToolExit in tests.
common.dart is a large-and-growing file containing all shared code,
which makes it hard to navigate. To make maintenance easier, this splits
the file (and its test file) into separate files for each major
component or category.
