Fix #28: Add Firefox/Marionette/Tape-based test suite.

Adds an automated test suite that runs JS tests using Tape. The tests are
run in Firefox using the remote code execution capabilities of Marionette.

Marionette's only well-maintained client is in Python, so we also have to add
Python dependencies, including a Pipfile.

bin/run_tests.py contains most of the plumbing for getting the test JS running,
including bundling it with Webpack, launching Firefox, and formatting the
output.

.circleci/config.yml

@@ -2,13 +2,16 @@ version: 2
 jobs:
   build:
     docker:
-      - image: circleci/node:10-browsers
+      - image: circleci/python:2.7-node-browsers
     steps:
       - checkout
       - run:
           name: Install dependencies
           command: |
+            pipenv install
             npm install
+            pipenv run mozdownload --version latest --destination $HOME/firefox.tar.bz2
+            pipenv run mozinstall --destination $HOME $HOME/firefox.tar.bz2
       - run:
           name: Build extension
           command: |
@@ -17,9 +20,15 @@ jobs:
           name: Run linting checks
           command: |
             npm run lint
+      - run:
+          name: Run automated tests
+          command: |
+            pipenv run test -- --firefox_bin $HOME/firefox/firefox
       - run:
           name: Package extension as XPI
           command: |
             npm run package
       - store_artifacts:
           path: web-ext-artifacts
+      - store_artifacts:
+          path: gecko.log

.gitignore

@@ -1,3 +1,4 @@
 node_modules
 web-ext-artifacts
 build
+gecko.log

Pipfile

@@ -0,0 +1,18 @@
+[[source]]
+url = "https://pypi.org/simple"
+verify_ssl = true
+name = "pypi"
+
+[dev-packages]
+
+[packages]
+click = "*"
+marionette-client = "*"
+mozdownload = "*"
+mozinstall = "*"
+
+[requires]
+python_version = "2.7"
+
+[scripts]
+test = "npm test"

README.md

@@ -30,7 +30,35 @@ Prerequisites:
    npm start
    ```
 
-## NPM Scripts
+## Running Tests
+
+Automated tests are run in a Firefox browser instance using [Marionette][]. We use the Python client for Marionette since there is no up-to-date JavaScript client.
+
+To set up your environment for running the tests, you must have:
+
+- A Firefox binary. On MacOS, this can be found within the `.app` folder at  `Firefox.app/Contents/MacOS/firefox`.
+- Python 2.7
+- [Pipenv][]
+
+With these installed, you can set up the test suite:
+
+1. Install Python dependencies:
+
+   ```sh
+   pipenv install
+   ```
+2. Save the path to your Firefox binary with `npm`:
+
+   ```sh
+   npm config set webext-commerce:firefox_bin <PATH_TO_FIREFOX_BINARY>
+   ```
+
+After this, you can run `pipenv run test` to run the automated test suite.
+
+[Marionette]: https://firefox-source-docs.mozilla.org/testing/marionette/marionette/index.html
+[Pipenv]: https://docs.pipenv.org/
+
+## Scripts
 
 | Command | Description |
 | --- | --- |
@@ -39,6 +67,7 @@ Prerequisites:
 | `npm run build` | Compile source files with Webpack |
 | `npm run watch` | Watch for changes and rebuild |
 | `npm run package` | Package the extension into an XPI file |
+| `pipenv run test` | Run test suite (See "Running Tests" for setup) |
 
 ## License