Computing combined code coverage with Tox

.coveragerc

[run]
source =
  greet

[paths]
source =
  .
  .tox/py27/lib/python2.7/site-packages/
  .tox/py34/lib/python3.4/site-packages/
  .tox/pypy/site-packages/
  .tox/pypy3/site-packages/

tox-combined-coverage

This snippet shows how to configure Tox to compute combined code coverage after all other tets have run.

Notes:
- replace `greet` with the name of your Python package;
- the `coverage` environment *must* appear last in `envlist`;
- `coverage combine` will delete all temporary `.coverage.{envname}` files and replace them with a single `.coverage` file;
- you can run `coverage html` after `tox` to get an HTML report that highlights the source lines that were not covered by any environment.

tox.ini

[tox]
envlist =
  coverage-erase,
  py34,
  py27,
  pypy3,
  pypy,
  coverage-report,


[testenv]
deps =
  nose
  coverage
setenv =
  COVERAGE_FILE=.coverage.{envname}
commands =
  coverage run -m nose greet


[testenv:coverage-erase]
deps =
  coverage
commands =
  coverage erase


[testenv:coverage-report]
deps =
  coverage
setenv =
  COVERAGE_FILE=.coverage
commands =
  coverage combine
  coverage report --fail-under=100