Test harness

[blaix]

• Newly initialized projects should have gren-effectful-tests set up, and the following modules via the project template:
  • Tests.Unit with an example 1 + 1 test
  • Tests.Integration with example Task.succeed and Task.fail
  • Tests.Browser that runs the dev site in the background, verifies the example site through a browser (check static content, click + and verify counter increments), then kills the dev site.
  • Tests that runs all of them.
• They should each have their own main so they can be run with gren run.
• The project template's npm test should run gren run Tests.
• The prettynice project itself should have a just target that initializes a new project and verifies its npm test.