setup.py installs the tests package

[dgilman]

This might be partly a bug in poetry but the sdist tarball's setup.py installs the tests package alongside the cachy package.

[kwshi]

Related issues/PRs:

• 1.0.3: tests/ directory missing in idst pypy tar ball python-poetry/poetry#3952, dist: add tests to sdists python-poetry/poetry#4007, Include tests in sdist python-poetry/poetry-core#173
• Including tests dir in sdist breaks install python-poetry/poetry#2353
• setup.py installs the tests package python-poetry/tomlkit#69, Remove "tests" package from sdist installation python-poetry/tomlkit#120

The issue is, I believe, caused by including tests under the package clause (where it should be included under include, and therefore not exposed as a package for installations).