Run mocha in browser with karma runner

Author: Yukaii

.github/workflows/nodejs.yml

@@ -22,3 +22,4 @@ jobs:
         npm install
         npm run build --if-present
         npm test
+        npm run test:browser

karma.conf.js

@@ -0,0 +1,23 @@
+process.env.CHROME_BIN = require('puppeteer').executablePath()
+
+module.exports = function(config) {
+  config.set({
+    browsers: ['ChromeHeadless'],
+
+    frameworks: ['mocha', 'chai'],
+
+    files: [
+        'tests/spec/*.test.js'
+    ],
+
+    singleRun: true,
+
+    client: {
+        mocha: {
+          require: [
+                require.resolve('./dist/js/emojify-browser.min.js')
+            ]
+        }
+    }
+  })
+}