test: metro-compat resolution tests

[jbroma]

Summary

This PR introduces metro-compat package which houses tests suites designed for checking compatibility with parts of metro.

Right now, tests include resolver tests directly imported from metro-resolver from here

Test environment is modified to accommodate for how enhanced-resolve works. Basic principle is this: use unchanged tests and provide compatible resolve function for tests. While in metro-resolver everything happens via mocked methods for checking whether file exists, our tests create a fresh in-memory filesystem for each test to test resolution against, which yields more ensuring results.

Some tests suite are skipped:

• assets-test.js - because enhanced-resolve, like node resolution, returns only a single entry, it's impossible to support these test cases. We handle this differently using AssetResolver which provides you with first matching entry for development, but all scales are exposed to the runtime
• index-test.js - this suite contains some basic tests & failure tests which we could include but most of it contains tests for unsupported features like:
  • resolveRequest - this is essentially a custom resolver or a plugin, it should be documented how to achieve similar functionality in Re.Pack
  • redirectModulePath - this is equal to alias field in enhanced-resolve, if end user wants to do this dynamically, then custom resolver/plugin should be used for that - also needs to documented
  • disableHierarchicalLookup - can be achieved in enhanced-resolve by using modules - also needs to be documented

Some test cases are skipped (all come from package-exports-test.js):

• [nonstrict] tests are skipped because we don't support fallback in form of legacy file resolution
• asset tests with package exports enabled are skipped for the same reason as above (regarding the assets)
• rest of the test skipped are due to inline snapshot not matching up with what enhanced-resolve returns - this could be potentially fixed by trapping toThrowErrorMatchingInlineSnapshot calls and checking for existence of errors only

Tests will be excluded from CI for now until everything is aligned properly and some issues are brought up with metro team. Alignment of getResolveOptions will be done in a separate PR. Documentation will follow in a separate PR as well.

Side-note: this PR also unveiled few issues with package exports implementation in metro-resolver which will be investigated more throughly and perhaps become more aligned in the future.

Side-note 2: the way we skip tests without modyfing the test files is rather hacky, we trap jest.describe, jest.it & jest.test and we check if the test name matches, TBD whether there is a better way to do this.

Checklist

• metro-resolver test suite
• setup mocks
• setup skip list
• exclude tests from turborepo so they are not run with the rest of the tests
• cleanup
• README.md in metro-compat

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[jbroma]

Issue raised with metro: facebook/metro#1236

[jbroma]

@RafikiTiki don't mind the enabled tests failing for now, it's expected without reworking implementation