# Coverage.py

Coverage.py is a tool for measuring code coverage of Python programs. It monitors your program, noting which parts of the code have been executed, then analyzes the source to identify code that could have been executed but was not.

Coverage measurement is typically used to gauge the effectiveness of tests. It can show which parts of your code are being exercised by tests, and which are not.

The latest version is coverage.py 4.5.2, released November 12th 2018. It is supported on:

- Python versions 2.6, 2.7, 3.3, 3.4, 3.5, 3.6, 3.7, and pre-alpha 3.8.
- PyPy2 6.0 and PyPy3 6.0.
- Jython 2.7.1, though only for running code, not reporting.
- IronPython 2.7.7, though only for running code, not reporting.

Professional support for coverage.py is available as part of the Tidelift Subscription. Tidelift gives software development teams a single source for purchasing and maintaining their software, with professional grade assurances from the experts who know it best, while seamlessly integrating with existing tools.

Professional support for coverage.py is available as part of the Tidelift Subscription.

## Quick start

Getting started is easy:

1. Install coverage.py from the coverage.py page on the Python Package Index, or by using “pip install coverage”. For a few more details, see Installation.

2. Use `coverage run` to run your program and gather data:

       # if you usually do:
       #
       #   $ python my_program.py arg1 arg2
       #
       # then instead do:

       $ coverage run my_program.py arg1 arg2
       blah blah ..your program's output.. blah blah

3. Use `coverage report` to report on the results:

       $ coverage report -m
       Name                      Stmts   Miss  Cover   Missing
       -------------------------------------------------------
       my_program.py                20      4    80%   33-35, 39
       my_other_module.py           56      6    89%   17-23
       -------------------------------------------------------
       TOTAL                        76     10    87%

4. For a nicer presentation, use `coverage html` to get annotated HTML listings detailing missed lines:

       $ coverage html

   Then visit htmlcov/index.html in your browser, to see a report like this.

## Using coverage.py

There are a few different ways to use coverage.py. The simplest is the command line, which lets you run your program and see the results. If you need more control over how your project is measured, you can use the API.

Some test runners provide coverage integration to make it easy to use coverage.py while running tests. For example, pytest has the pytest-cov plugin.

You can fine-tune coverage.py’s view of your code by directing it to ignore parts that you know aren’t interesting. See Specifying source files and Excluding code from coverage.py for details.

## Getting help

If the FAQ doesn’t answer your question, you can discuss coverage.py or get help using it on the Testing In Python mailing list.

Bug reports are gladly accepted at the GitHub issue tracker. GitHub also hosts the code repository.

Professional support for coverage.py is available as part of the Tidelift Subscription.

I can be reached in a number of ways. I’m happy to answer questions about using coverage.py.

## More information

- Installation
- Coverage.py command line usage
- Configuration files
- Specifying source files
- Excluding code from coverage.py
- Branch coverage measurement
- Measuring sub-processes
- Coverage.py API
- How Coverage.py works
- Plug-ins
- Contributing to coverage.py
- Things that cause trouble
- FAQ and other help
- Change history for Coverage.py