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diff --git a/tests/coverage/README.md b/tests/coverage/README.md new file mode 100644 index 00000000000..f1e403c65e3 --- /dev/null +++ b/tests/coverage/README.md @@ -0,0 +1,16 @@ +The tests in this directory are shared by two different test modes, and can be +run in multiple different ways: + +- `./x.py test coverage-map` (compiles to LLVM IR and checks coverage mappings) +- `./x.py test run-coverage` (runs a test binary and checks its coverage report) +- `./x.py test coverage` (runs both `coverage-map` and `run-coverage`) + +## Maintenance note + +These tests can be sensitive to small changes in MIR spans or MIR control flow, +especially in HIR-to-MIR lowering or MIR optimizations. + +If you haven't touched the coverage code directly, and the tests still pass in +`run-coverage` mode, then it should usually be OK to just re-bless the mappings +as necessary with `./x.py test coverage-map --bless`, without worrying too much +about the exact changes. |