Can I combine mypy reports with pytest coverage reports?

Question

I can generate a type "coverage" report with mypy via

mypy . --html-report mypy-report

and a pytest coverage report with pytest-cov

pytest --cov=app --cov-report=html

Is there a way to combine both reports? I would be interested in code that is neither covered by unit tests nor by mypy.

Monarchal

Don't know of an existing solution, but are you locked into HTML? Using line coverage from mypy (--lineprecision-report) and pytest would make parsing the common coverage much easier. – Oxime

Answer 1

I spent a little time on this, and made some progress, but don't have a fully working solution.

Both pytest and mypy have flags to emit an XML-based report, and the one common schema they share is for the Java-based Cobertura tool.

Example invocation to produce an XML file for each:

pytest --cov=app --cov-report=xml:pytest-cobertura.xml
mypy app.py --cobertura-xml-report .

After this, you'll have two similar XML files named:

• pytest-cobertura.xml
• coverage.xml - mypy will only allow a directory, not a filename

I've explored trying to merge these two files into a single one, but haven't been able to successfully do so in the time I've spent on this - but it should be something along the lines of parsing the XML tree and merging the two sets of lines XML tags and creating a combined.xml file.

Right now, each file individually can be rendered to either terminal or HTML with the pycobertura tool, like so:

pycobertura show --format html --output coverage.html combined.xml

I haven't been able to figure out the merging just yet, but wanted to give you what I had figured out.

Crouch