WIP

gulpfile.babel.js/karma.conf.js

@@ -0,0 +1,58 @@
+// Karma configuration
+if (!process.env.NODE_ENV) {
+    process.env.NODE_ENV = 'test';
+}
+
+module.exports = function (config) {
+    const tests = './client/**/__tests__/*.spec.js';
+
+    config.set({
+
+        // base path that will be used to resolve all patterns (eg. files, exclude)
+        basePath: '../',
+
+        // frameworks to use
+        // available frameworks: https://npmjs.org/browse/keyword/karma-adapter
+        frameworks: ['ava'],
+
+        // list of files / patterns to load in the browser
+        files: [
+            tests
+        ],
+
+        // test results reporter to use
+        // possible values: 'dots', 'progress'
+        // available reporters: https://npmjs.org/browse/keyword/karma-reporter
+        // reporters: ['spec'],
+
+        // web server port
+        port: 9876,
+
+        // enable / disable colors in the output (reporters and logs)
+        colors: true,
+
+        // level of logging
+        // possible values: config.LOG_DISABLE || config.LOG_ERROR || config.LOG_WARN || config.LOG_INFO || config.LOG_DEBUG
+        logLevel: config.LOG_DEBUG,
+
+        // enable / disable watching file and executing tests whenever any file changes
+        autoWatch: true,
+
+        // start these browsers
+        // available browser launchers: https://npmjs.org/browse/keyword/karma-launcher
+        browsers: ['PhantomJS'],
+
+        // Continuous Integration mode
+        // if true, Karma captures browsers, runs the tests and exits
+        singleRun: false,
+
+        // Concurrency level
+        // how many browser should be started simultaneous
+        concurrency: Infinity,
+
+        // Ensure Karma doesn't use an iFrame.
+        client: {
+            useIframe: false
+        }
+    });
+};

gulpfile.babel.js/test.js

@@ -1,11 +1,20 @@
 const gulp = require('gulp');
-const ava = require('gulp-ava');
+const gutil = require('gulp-util');
+const { Server } = require('karma');
 
 gulp.task('test', ['test:unit']);
 
-gulp.task('test:unit', () => {
+gulp.task('test:unit', done => {
     process.env.BABEL_ENV = 'test';
 
-    return gulp.src('../client/**/__tests__/*.spec.js')
-        .pipe(ava({ verbose: true }));
+    const server = new Server({
+        configFile: __dirname + '/karma.conf.js',
+        singleRun: true
+    }, () => {
+        gutil.log('Tests complete');
+
+        done();
+    });
+
+    server.start();
 });

package.json

@@ -36,7 +36,12 @@
     "gulp-wp-pot": "1.0.1",
     "handlebars": "^4.0.5",
     "handlebars-loader": "^1.1.4",
+    "karma": "^1.4.0",
+    "karma-ava": "git+ssh://git@github.com/avajs/karma-ava.git",
+    "karma-phantomjs-launcher": "^1.0.2",
+    "karma-spec-reporter": "0.0.26",
     "node-notifier": "^4.6.1",
+    "phantomjs-prebuilt": "^2.1.14",
     "sass-loader": "^4.0.2",
     "style-loader": "^0.13.1",
     "webpack": "2.2.0-rc.3",