| .. Licensed under the Apache License: http://www.apache.org/licenses/LICENSE-2.0 |
| .. For details: https://bitbucket.org/ned/coveragepy/src/default/NOTICE.txt |
| |
| .. _faq: |
| |
| ================== |
| FAQ and other help |
| ================== |
| |
| .. :history: 20090613T141800, brand new docs. |
| .. :history: 20091005T073900, updated for 3.1. |
| .. :history: 20091127T201500, updated for 3.2. |
| .. :history: 20110605T175500, add the announcement mailing list. |
| .. :history: 20121231T104700, Tweak the py3 text. |
| |
| |
| Frequently asked questions |
| -------------------------- |
| |
| **Q: I use nose to run my tests, and its cover plugin doesn't let me create |
| HTML or XML reports. What should I do?** |
| |
| First run your tests and collect coverage data with `nose`_ and its plugin. |
| This will write coverage data into a .coverage file. Then run coverage.py from |
| the :ref:`command line <cmd>` to create the reports you need from that data. |
| |
| .. _nose: http://nose.readthedocs.io |
| |
| |
| **Q: Why do unexecutable lines show up as executed?** |
| |
| Usually this is because you've updated your code and run coverage.py on it |
| again without erasing the old data. Coverage.py records line numbers executed, |
| so the old data may have recorded a line number which has since moved, causing |
| coverage.py to claim a line has been executed which cannot be. |
| |
| If you are using the ``-x`` command line action, it doesn't erase first by |
| default. Switch to the ``coverage run`` command, or use the ``-e`` switch to |
| erase all data before starting the next run. |
| |
| |
| **Q: Why do the bodies of functions (or classes) show as executed, but the def |
| lines do not?** |
| |
| This happens because coverage.py is started after the functions are defined. |
| The definition lines are executed without coverage measurement, then |
| coverage.py is started, then the function is called. This means the body is |
| measured, but the definition of the function itself is not. |
| |
| To fix this, start coverage.py earlier. If you use the :ref:`command line |
| <cmd>` to run your program with coverage.py, then your entire program will be |
| monitored. If you are using the :ref:`API <api>`, you need to call |
| coverage.start() before importing the modules that define your functions. |
| |
| |
| **Q: Coverage.py is much slower than I remember, what's going on?** |
| |
| Make sure you are using the C trace function. Coverage.py provides two |
| implementations of the trace function. The C implementation runs much faster. |
| To see what you are running, use ``coverage debug sys``. The output contains |
| details of the environment, including a line that says either |
| ``tracer: CTracer`` or ``tracer: PyTracer``. If it says ``PyTracer`` then you |
| are using the slow Python implementation. |
| |
| Try re-installing coverage.py to see what happened and if you get the CTracer |
| as you should. |
| |
| |
| **Q: Isn't coverage testing the best thing ever?** |
| |
| It's good, but `it isn't perfect`__. |
| |
| __ http://nedbatchelder.com/blog/200710/flaws_in_coverage_measurement.html |
| |
| |
| .. Other resources |
| --------------- |
| |
| There are a number of projects that help integrate coverage.py into other |
| systems: |
| |
| - `trialcoverage`_ is a plug-in for Twisted trial. |
| |
| .. _trialcoverage: http://pypi.python.org/pypi/trialcoverage |
| |
| - `pytest-coverage`_ |
| |
| .. _pytest-coverage: http://pypi.python.org/pypi/pytest-coverage |
| |
| - `django-coverage`_ for use with Django. |
| |
| .. _django-coverage: http://pypi.python.org/pypi/django-coverage |
| |
| |
| **Q: Where can I get more help with coverage.py?** |
| |
| You can discuss coverage.py or get help using it on the `Testing In Python`_ |
| mailing list. |
| |
| .. _Testing In Python: http://lists.idyll.org/listinfo/testing-in-python |
| |
| Bug reports are gladly accepted at the `Bitbucket issue tracker`_. |
| |
| .. _Bitbucket issue tracker: http://bitbucket.org/ned/coveragepy/issues |
| |
| Announcements of new coverage.py releases are sent to the |
| `coveragepy-announce`_ mailing list. |
| |
| .. _coveragepy-announce: http://groups.google.com/group/coveragepy-announce |
| |
| `I can be reached`__ in a number of ways, I'm happy to answer questions about |
| using coverage.py. |
| |
| __ http://nedbatchelder.com/site/aboutned.html |
| |
| |
| History |
| ------- |
| |
| Coverage.py was originally written by `Gareth Rees`_. |
| Since 2004, `Ned Batchelder`_ has extended and maintained it with the help of |
| `many others`_. The :ref:`change history <changes>` has all the details. |
| |
| .. _Gareth Rees: http://garethrees.org/ |
| .. _Ned Batchelder: http://nedbatchelder.com |
| .. _many others: http://bitbucket.org/ned/coveragepy/src/tip/CONTRIBUTORS.txt |