Smoke tests for discourse-setup

These are not real tests, but do test that discourse-setup can produce or modify the YML file as expected.

Tests will not run if yml files exist already. If the tests succeed, the container files are deleted.

standalone tests

• run the first time to do an initial creation of app.yml and that the values get set as expected.
• run again to change the values

two-container tests

• run with --two-container switch to create separate data and web containers
• run again (not requiring the --two-container switch) and update values as expected

update-old-templates tests

• updates a very old (Sep 6, 2016) standalone.yml
• updates a pretty old (Apr 13, 2018) web_only.yml

The tests won't run if app.yml or web_only.yml exist.

run-all-tests

Runs all three of the above tests and prints an error if app.yml or web_only.yml exist.