Initial implementation of some karma/mocha tests

It does something, but things I don't like:

* it churns for 15 seconds webpacking everything. Do we really need to get
  webpack involved here?

* I don't think there's any way to control which tests get run and which don't.

Other things I'd want to fix up include:

* Make it run on jsdom or phantomjs instead of Chrome
* figure out how to configure babel without a .babelrc

.babelrc

@@ -0,0 +1,3 @@
+{
+  "presets": ["react", "es2015"]
+}

karma.conf.js

@@ -0,0 +1,39 @@
+// karma.conf.js
+var webpack = require('webpack');
+var path = require('path');
+
+module.exports = function (config) {
+    config.set({
+        browsers: ['Chrome'],
+        singleRun: true,
+        frameworks: ['mocha'],
+        files: [
+            'tests/tests.js'
+        ],
+        preprocessors: {
+            'tests/tests.js': ['webpack', 'sourcemap']
+        },
+        reporters: ['dots'],
+        webpack: {
+            module: {
+                loaders: [
+                    { test: /\.json$/, loader: "json" },
+                    { test: /\.js$/, loader: "babel", include: path.resolve('./src') },
+                ],
+                noParse: [
+                    // don't parse the languages within highlight.js. They
+                    // cause stack overflows
+                    // (https://github.com/webpack/webpack/issues/1721), and
+                    // there is no need for webpack to parse them - they can
+                    // just be included as-is.
+                    /highlight\.js\/lib\/languages/,
+                ],
+            },
+            resolve: {
+                alias: {
+                    'matrix-react-sdk': path.resolve('src/index.js'),
+                },
+            },
+        },
+    });
+};

package.json

@@ -17,7 +17,9 @@
     "build": "babel src -d lib --source-maps",
     "start": "babel src -w -d lib --source-maps",
     "clean": "rimraf lib",
-    "prepublish": "npm run build; git rev-parse HEAD > git-revision.txt"
+    "prepublish": "npm run build; git rev-parse HEAD > git-revision.txt",
+    "test": "karma start",
+    "test-multi": "karma start --single-run=false"
   },
   "dependencies": {
     "classnames": "^2.1.2",
@@ -45,6 +47,15 @@
     "json-loader": "^0.5.3",
     "require-json": "0.0.1",
     "rimraf": "^2.4.3",
-    "source-map-loader": "^0.1.5"
+    "source-map-loader": "^0.1.5",
+
+    "karma": "^0.0.0",
+    "karma-cli": "^0.0.0",
+    "karma-mocha": "^0.0.0",
+    "karma-webpack": "^0.0.0",
+    "karma-sourcemap-loader": "^0.0.0",
+    "karma-chrome-launcher": "^0.0.0",
+    "mocha": "^0.0.0",
+    "expect": "^0.0.0"
   }
 }

tests/components/structures/MatrixChat-test.js

@@ -0,0 +1,11 @@
+var React = require('react');
+var expect = require('expect');
+
+var sdk = require("matrix-react-sdk");
+
+var MatrixChat = sdk.getComponent('structures.MatrixChat');
+
+describe('MatrixChat', function () {
+    it('does something', function () {
+    });
+});

tests/tests.js

@@ -0,0 +1,11 @@
+// tests.js
+//
+// Our master test file: uses the webpack require API to find our test files
+// and run them
+
+// this is a handly place to make sure the sdk has been skinned
+var sdk = require("matrix-react-sdk");
+sdk.loadSkin(require('../src/component-index'));
+
+var context = require.context('.', true, /-test\.jsx?$/);
+context.keys().forEach(context);