Add browser tests via karma

.gitignore

@@ -7,3 +7,6 @@ typings/
 typings.json
 node_modules/
 dist/
+*.env
+coverage/
+npm-debug.log

.travis.yml

@@ -1,3 +1,4 @@
+sudo: false
 language: node_js
 node_js:
   - "5"
@@ -6,10 +7,14 @@ node_js:
   - "8"
   - "node"
 
-sudo: false
+addons:
+  chrome: stable
+  firefox: latest
+
 script:
   - npm test
   - npm run lint
+  - npm run browser-test
 
 git:
   depth: 1

ci/spec-bundle.js

@@ -0,0 +1,7 @@
+var testContext = require.context("../src", true, /\.spec\.ts$/);
+
+function requireAll(context) {
+    return context.keys().map(context);
+}
+
+var modules = requireAll(testContext);

karma.conf.js

@@ -0,0 +1,54 @@
+module.exports = function(config) {
+    var configuration = {
+        frameworks: ["jasmine"],
+        files: [
+            {pattern: './ci/spec-bundle.js', watched: false}
+        ],
+        preprocessors: {
+            './ci/spec-bundle.js': ['webpack', 'sourcemap'],
+        },
+        webpackMiddleware: {
+            scripts: 'errors-only'
+        },
+        webpack: {
+            devtool: "inline-source-map",
+            resolve: {
+                extensions: ['.ts', '.js'],
+            },
+            module: {
+                rules: [
+                    {
+                        test: /\.ts$/,
+                        exclude: /node_modules/,
+                        use: [{loader: 'ts-loader', options: {transpileOnly: true}}]
+                    }
+                ]
+            },
+        },
+        mime: {
+            'text/x-typescript': ['ts', 'tsx']
+        },
+        reporters: ["progress"],
+        browsers: ["ChromeHeadless", "FirefoxHeadless"],
+        customLaunchers: {
+            ChromeHeadlessTravis: {
+                base: "ChromeHeadless",
+                flags: ['--no-sandbox']
+            }
+        },
+        concurrency: 8,
+        plugins: [
+            'karma-jasmine',
+            'karma-chrome-launcher',
+            'karma-firefox-launcher',
+            'karma-webpack',
+            'karma-sourcemap-loader'
+        ]
+    };
+
+    if (process.env.TRAVIS) {
+        configuration.browsers = ['ChromeHeadlessTravis', 'FirefoxHeadless'];
+    }
+
+    config.set(configuration);
+}

package.json

@@ -13,11 +13,20 @@
     "gulp-tslint": "^8.1.2",
     "gulp-typescript": "^3.2.3",
     "tslint": "^5.8.0",
-    "typescript": "^2.6.2"
+    "typescript": "^2.6.2",
+    "webpack": "^3.10.0",
+    "karma": "^2.0.0",
+    "karma-jasmine": "^1.1.1",
+    "karma-chrome-launcher": "^2.2.0",
+    "karma-firefox-launcher": "^1.1.0",
+    "karma-webpack": "^2.0.9",
+    "karma-sourcemap-loader": "^0.3.7",
+    "ts-loader": "^3.3.1"
   },
   "scripts": {
     "test": "gulp test",
-    "lint": "gulp lint"
+    "lint": "gulp lint",
+    "browser-test": "karma start --single-run"
   },
   "repository": {
     "type": "git",