pytest-cov 1.6 (beta)

py.test plugin for coverage reporting with support for both centralised and distributed testing, including subprocesses and multiprocessing

Installation

Install with pip:

pip install pytest-cov

For distributed testing support install pytest-xdist:

pip install pytest-xdist

Uninstallation

Uninstall with pip:

pip uninstall pytest-cov
pip uninstall cov-core

Usage

py.test --cov myproj tests/

-------------------- coverage: platform linux2, python 2.6.4-final-0 ---------------------
Name                 Stmts   Miss  Cover
----------------------------------------
myproj/__init__          2      0   100%
myproj/myproj          257     13    94%
myproj/feature4286      94      7    92%
----------------------------------------
TOTAL                  353     20    94%

py.test --cov myproj -n 2 tests/

-------------------- coverage: platform linux2, python 2.6.4-final-0 ---------------------
Name                 Stmts   Miss  Cover
----------------------------------------
myproj/__init__          2      0   100%
myproj/myproj          257     13    94%
myproj/feature4286      94      7    92%
----------------------------------------
TOTAL                  353     20    94%

py.test --cov myproj --dist load
        --tx ssh=memedough@host1//chdir=testenv1
        --tx ssh=memedough@host2//chdir=/tmp/testenv2//python=/tmp/env1/bin/python
        --rsyncdir myproj --rsyncdir tests --rsync examples
        tests/

-------------------- coverage: platform linux2, python 2.6.4-final-0 ---------------------
Name                 Stmts   Miss  Cover
----------------------------------------
myproj/__init__          2      0   100%
myproj/myproj          257     13    94%
myproj/feature4286      94      7    92%
----------------------------------------
TOTAL                  353     20    94%

py.test --cov myproj --dist each
        --tx popen//chdir=/tmp/testenv3//python=/usr/local/python27/bin/python
        --tx ssh=memedough@host2//chdir=/tmp/testenv4//python=/tmp/env2/bin/python
        --rsyncdir myproj --rsyncdir tests --rsync examples
        tests/

---------------------------------------- coverage ----------------------------------------
                          platform linux2, python 2.6.5-final-0
                          platform linux2, python 2.7.0-final-0
Name                 Stmts   Miss  Cover
----------------------------------------
myproj/__init__          2      0   100%
myproj/myproj          257     13    94%
myproj/feature4286      94      7    92%
----------------------------------------
TOTAL                  353     20    94%

Reporting

It is possible to generate any combination of the reports for a single test run.

The available reports are terminal (with or without missing line numbers shown), HTML, XML and annotated source code.

The terminal report without line numbers (default):

py.test --cov-report term --cov myproj tests/

-------------------- coverage: platform linux2, python 2.6.4-final-0 ---------------------
Name                 Stmts   Miss  Cover
----------------------------------------
myproj/__init__          2      0   100%
myproj/myproj          257     13    94%
myproj/feature4286      94      7    92%
----------------------------------------
TOTAL                  353     20    94%

The terminal report with line numbers:

py.test --cov-report term-missing --cov myproj tests/

-------------------- coverage: platform linux2, python 2.6.4-final-0 ---------------------
Name                 Stmts   Miss  Cover   Missing
--------------------------------------------------
myproj/__init__          2      0   100%
myproj/myproj          257     13    94%   24-26, 99, 149, 233-236, 297-298, 369-370
myproj/feature4286      94      7    92%   183-188, 197
--------------------------------------------------
TOTAL                  353     20    94%

The remaining three reports output to files without showing anything on the terminal (useful for when the output is going to a continuous integration server):

py.test --cov-report html
        --cov-report xml
        --cov-report annotate
        --cov myproj tests/

Coverage Data File

The data file is erased at the beginning of testing to ensure clean data for each test run.

The data file is left at the end of testing so that it is possible to use normal coverage tools to examine it.

Coverage Config File

This plugin provides a clean minimal set of command line options that are added to pytest. For further control of coverage use a coverage config file.

For example if tests are contained within the directory tree being measured the tests may be excluded if desired by using a .coveragerc file with the omit option set:

py.test --cov-config .coveragerc
        --cov myproj
        myproj/tests/

Where the .coveragerc file contains file globs:

[run]
omit = tests/*

For full details refer to the coverage config file documentation.

Note that this plugin controls some options and setting the option in the config file will have no effect. These include specifying source to be measured (source option) and all data file handling (data_file and parallel options).

Limitations

For distributed testing the slaves must have the pytest-cov package installed. This is needed since the plugin must be registered through setuptools / distribute for pytest to start the plugin on the slave.

For subprocess measurement environment variables must make it from the main process to the subprocess. The python used by the subprocess must have pytest-cov installed. The subprocess must do normal site initialisation so that the environment variables can be detected and coverage started.

Acknowledgements

Whilst this plugin has been built fresh from the ground up it has been influenced by the work done on pytest-coverage (Ross Lawley, James Mills, Holger Krekel) and nose-cover (Jason Pellerin) which are other coverage plugins.

Ned Batchelder for coverage and its ability to combine the coverage results of parallel runs.

Holger Krekel for pytest with its distributed testing support.

Jason Pellerin for nose.

Michael Foord for unittest2.

No doubt others have contributed to these tools as well.