plugins/sources/pip.py: Accomodate characters '-','.','_' for packages
Description
This MR fixes the regex in plugins/sources/pip.py used to parse out the package name and package version from a downloaded source distribution such that it accommodates the characters '-', '.' and '_' in package names.
Changes proposed in this merge request:
- Modify
_SDIST_RE
to accommodate '-', '.' and '_' in package names - Move the code that actually does the regex-matching to a separate function
- Add a regression test to tests/sources/pip.py for parsing the source distributions
- Add a testutil for generating dummy pip packages in a dummy python repository
- Remove tests/integration/files/pypi-repo as these test pip packages can now be generated
- Generate and test exotically named packages in tests/integration/pip_source.py