I have project with very simple configuration matrix, described in tox: py{27,35}-django{18,19}
I'm using TeamCity as the CI-server, run tests with py.test with installed teamcity-messages. I've tried to run every configuration like tox -e py27-django18 in different steps. But Teamcity didn't summarize tests and didn't accumulate coverage for files, it's only count coverage for last run and Tests passed:​ ... show tests from only one build.
How testing with multiple Python configurations can be integrated into Teamcity?
upd. Find out, that coverage counts correctly, just forgot to add --cov-append option to py.test.
TeamCity counts the tests based on their names. My guess is since your tests in the tox matrix have the same name, they are counted as one test. This should be visible on the test page of your build, where you can see invocation counts of each test.
For TeamCity to report number of tests correctly, test names must differ in different configurations. Perhaps, you could include configuration details in the reported test name
Testing python project with Tox and Teamcity