faif / python-patterns

pyupgrade --py36-plus **/*.py

Make codespell and isort mandatory tests

Make codespell and isort mandatory tests.

Drop bandit whose test results are not enlightening.

GitHub Action to lint Python code

Travis CI: Test on Python 3.9

Fix typo discovered by codespell

https://www.grammarly.com/blog/cannot-or-can-not/

___codespell --quiet-level=2___
```
./python-patterns/patterns/behavioral/publish_subscribe.py:68: subscirbed ==> subscribed
./python-patterns/patterns/structural/front_controller.py:30: cant ==> can't
./python-patterns/patterns/structural/front_controller.py:72: cant ==> can't
```

Added base case and return the path as soon as end node is visited

Used correct function names in recursive calls and fixed the doctest

Implemented breadth first search for shortest graph path in graph_search.py

Update tox.ini to use py37,py38 instead of ci37,ci38

As defined in the tox documentation
(https://tox.readthedocs.io/en/latest/config.html#tox-environments),
environment with names "pyNM" have special meaning and implicitly define
the Python interpreter.

Environment names ci37 and ci38 don't have any special meaning and run
the default version of the interpreter. This results in that that both
environments use the same interpreter locally.

The PR changes the names of environments to make sure that tox creates a
virtual environment with the correct interpreter version.

Fix tests

Make the flake8's "F541 f-string is missing placeholders" happy

Make the flake8's test "F401 imported but unused" happy.

As defined in https://www.flake8rules.com/rules/W503.html, this rule
goes against the PEP8 recommendation and conflicts with W504.

In the code, the rule results in a false-positive in
patterns/behavioral/specification.py.

Add a tearDown method that sets the shared state to "Init"

Remove outdated tests and replace them with ones that check the new
behavior.

Added type hints to observer pattern