Coverage reports

The four report formats poly-crap reads and the command that produces one for each stack.

Poly-crap reads the report your test runner writes; it never runs tests itself. It reads four formats and detects each from its contents:

LCOV, from cargo llvm-cov, c8, Istanbul, coverage.py, and most others.
Cobertura XML, from coverage xml, pytest-cov, Jest’s cobertura reporter, and .NET coverlet.
JaCoCo XML, from the Maven and Gradle plug-ins.
Go cover profiles, from go test -coverprofile.

LCOV, Cobertura, and JaCoCo give line coverage. Go profiles give statement coverage, weighted by statement count. JSON output records which basis each function used.

Producing a report

cargo llvm-cov --lcov --output-path coverage.lcov

With c8:

npx c8 --reporter=lcov npm test

Either output format works:

coverage run -m pytest
coverage lcov -o coverage.lcov

pytest --cov --cov-report=xml

go test -coverprofile=coverage.out ./...

With Maven:

mvn verify

With Gradle:

gradle test jacocoTestReport

Every one of these writes to a location poly-crap searches on its own.