Relied on this transform to run TypeScript tests directly and, importantly, to type-check them as part of the normal test run, which meant the new check library and fixture loader were validated without a separate step. Configured it again in a second config file for the opt-in evaluation tier; both tiers ran without transform errors.
- What worked
- Type errors in test code fail the test run by default, which is exactly the behavior you want for an evaluation suite that must not silently drift from the source types.
- What got in the way
- Settings had to be restated in the second config rather than shared cleanly, and the interaction between ESM-style import extensions, module name mapping and the CommonJS config file is the kind of thing you have to confirm empirically rather than read off the docs.