Added Github Actions workflow to run npm test script

Also replaced phantomjs with chrome headless,
and removed puppeteer as part of modernizing
the test setup.

.github/workflows/ci.yaml

@@ -0,0 +1,42 @@
+name: Lint and Test
+
+on:
+    push:
+        branches: [ master ]
+    pull_request:
+        branches: [ master ]
+
+jobs:
+    test:
+        runs-on: ubuntu-latest
+
+        strategy:
+            matrix:
+                node-version: [10, 12, 14]
+
+        steps:
+            - uses: actions/checkout@v3
+
+            - name: Use Node.js ${{ matrix.node-version }}
+              uses: actions/setup-node@v3
+              with:
+                  node-version: ${{ matrix.node-version }}
+
+            - name: Setup Chrome
+              uses: browser-actions/setup-chrome@latest
+              with:
+                  chrome-version: stable
+
+            - name: Configure Chrome Sandbox
+              run: |
+                  sudo chown root:root /opt/hostedtoolcache/setup-chrome/chromium/stable/x64/chrome-sandbox
+                  sudo chmod 4755 /opt/hostedtoolcache/setup-chrome/chromium/stable/x64/chrome-sandbox
+
+            - name: Install dependencies
+              run: npm install
+
+            - name: Run ESLint and tests
+              run: npm test
+              env:
+                  CHROME_BIN: chrome
+                  CHROME_FLAGS: --no-sandbox --headless --disable-gpu

karma.conf.js

@@ -31,6 +31,18 @@ module.exports = function ( config ) {
 		port: 9876,
 
 		logLevel: config.LOG_INFO,
-		browsers: [ 'PhantomJS' ]
+		browsers: [ 'ChromeHeadless' ],
+		customLaunchers: {
+			ChromeHeadless: {
+				base: 'Chrome',
+				flags: [
+					'--no-sandbox',
+					'--headless',
+					'--disable-gpu',
+					'--disable-dev-shm-usage',
+					'--disable-software-rasterizer'
+				]
+			}
+		}
 	} );
 };

package.json

@@ -37,7 +37,7 @@
 		"eslint-config-wikimedia": "0.4.0",
 		"karma": "^6.1.0",
 		"karma-cli": "^1.0.1",
-		"karma-phantomjs-launcher": "^1.0.4",
+		"karma-chrome-launcher": "^3.1.0",
 		"karma-qunit": "^4.1.2",
 		"qunit": "^2.14.0"
 	},