How to get report for test coverage?

Question

I have a buildspec file like this:

version: 0.2


phases:
  install:
    commands:
      - pip install pytest
      - pip install pytest-cov
      - pip install .

  build:
    commands:
      - python -m pytest --junitxml=unittests.xml 

reports:
  unit_tests:
    files:
      - unittests.xml
    file-format: JUNITXML

which builds successfully and I can view my report under Report groups as expected.

Now I would like to extend it and also see the coverage using the option --cov-report. I tried

version: 0.2


phases:
  install:
    commands:
      - pip install pytest
      - pip install pytest-cov
      - pip install .

  build:
    commands:
      - python -m pytest --junitxml=unittests.xml --cov-report=xml:coverage.xml

reports:
  unit_tests:
    files:
      - unittests.xml
    file-format: JUNITXML
  coverage_tests:
    files:
      - coverage.xml
    file-format: COBERTURAXML

but without success. I get the output:

 generated xml file: /codebuild/output/<removed>/unittests.xml
 ... <skipped a few lines here>
 Report export config is NO_EXPORT, skip exporting reports
 Preparing to copy CODE_COVERAGE report coverage_tests
 Expanding base directory path:  .
 Assembling file list
 Expanding .
 Expanding file paths for base directory .
 Assembling file list
 Expanding coverage.xml
 Skipping invalid file path coverage.xml
 No matching report paths found
 Phase complete: UPLOAD_ARTIFACTS State: SUCCEEDED
 Phase context status code:  Message: 
 Error in UPLOAD_ARTIFACTS phase: [coverage_tests: [report files not
 found in build]]

How can I create the report properly?

Answer 1

As pointed out by @TeejayBruno in the comments, I missed the required flag.

When I use (rest of the file unchanged)

- python -m pytest --junitxml=unittests.xml --cov-report=xml --cov=ronwo --cov-branch

everything works as expected.