When I run "coverage html" on windows I get an htmlcov folder with one file for each source file in my project + an index.html file and a handful of .js, .css, and .png files. The report looks great.
When I do the same on linux, htmlcov also fills up with files for all source code in site-packages (i.e. dist-packages and /usr/share/pyshared on debian), and the .js, .css, etc. files are not included -- and index.html is not created.
I've installed by using pip install --upgrade coverage on both systems.
The only change I've made (on both systems) is to add an except:/pass clause in backwards.py to skip writing of html files where the file content is not decodable from utf8.
The command I used to create coverage data was:
coverage -x c:\Python26\Scripts\py.test-2.6-script.py
on windows, and
coverage -x /usr/local/bin/py.test