All reports of package-contains-python-tests-in-global-namespace for the archive. The extended description of this tag is:
This package appears to contain Python test files such as test_foo.py or test_foo/ in the global module namespace.
Whilst the tests may be useful in the binary package, it is probably a mistake to pollute the "top-level" namespace in this way.
Please install them to a subdirectory of the module being tested instead or simply omit from the binary package entirely.
This tag has not been emitted in any package tested by Lintian.