Description
In light of the discussion here, there's a need to re-evaluate the testing strategy for macro expansions, particularly concerning the application of fix-its. The current methodology asserts the expandedSource before the application of any fix-its, which may not fully validate the macro's behavior in the presence of fixable code errors.
A more robust testing process would involve the assertMacroExpansion function not only applying fix-its to the originalSource but also asserting the result of the macro expansion on the corrected source code. This approach has been effectively utilized in swift-macro-testing by mbrandonw and stephencelis, showcased here.
To align with this improved testing paradigm, I propose the addition of a new parameter—perhaps expandedSourceAfterApplyingFixIt—which would enable users to assert against the post-fix-it expanded source. This addition is crucial as macros may propose fix-its for diagnostics that do not halt the expansion process, such as those with a severity less than error.
By incorporating this feature, assertMacroExpansion would gain the capability to confirm the fixed source after the macro expansion, ensuring a more comprehensive verification process.