Basic CI test harness about datasette-app

[simonw]

Looks like spectron is the recommended tool for this: https://github.com/electron-userland/spectron

[simonw]

For the moment I'll run the tests in GitHub Actions in a macOS runner.

[simonw]

It's running here: https://github.com/simonw/datasette.app/runs/3413547090?check_suite_focus=true

Saw this warning:

npm WARN [email protected] license should be a valid SPDX license expression

Also:

     Error: Timeout of 10000ms exceeded. For async tests and hooks, ensure "done()" is called; if returning a Promise, ensure it resolves. (/Users/runner/work/datasette.app/datasette.app/test/spec.js)
      at listOnTimeout (internal/timers.js:557:17)
      at processTimers (internal/timers.js:500:7)

[simonw]

The list of licenses is on https://spdx.org/licenses/ - I want Apache-2.0.