QA and testing

new page, needs developing, for now just a bunch of notes

• HA dev docs Development Checklist
• Prerequisites for core integration PR
  • have a look at what came up with alex's previous PR
  • we need a documentation PR on the main doc repo too
    • like alex's previous doc PR and original doc PR
• Some QA checklist items for code structure from the 'great migration' that broke the previous warmup4ie
  • https://developers.home-assistant.io/blog/2019/04/12/new-integration-structure.html
  • https://developers.home-assistant.io/blog/2019/02/19/the-great-migration.html

Tutorial on Python Testing including a comparison of test runners.

CI test examples:

• tox -e py37 -- tests/components/your_components
• pylint homeassistant
• pre-commit run flake8 --all-files