diff --git a/.gitignore b/.gitignore
index 949e21b82b..8fdaf5903f 100644
--- a/.gitignore
+++ b/.gitignore
@@ -4,3 +4,6 @@
 # version file and tarball created by 'npm pack'
 /git-revision.txt
 /matrix-react-sdk-*.tgz
+
+# test reports created by karma
+/karma-reports
diff --git a/jenkins.sh b/jenkins.sh
index a2f28ffb8f..51fab5d020 100755
--- a/jenkins.sh
+++ b/jenkins.sh
@@ -14,6 +14,9 @@ npm install ./node_modules/matrix-js-sdk-*.tgz
 # install the other dependencies
 npm install
 
+# run the mocha tests
+npm run test
+
 # delete the old tarball, if it exists
 rm -f matrix-react-sdk-*.tgz
 
diff --git a/karma.conf.js b/karma.conf.js
new file mode 100644
index 0000000000..7a8831635b
--- /dev/null
+++ b/karma.conf.js
@@ -0,0 +1,121 @@
+// karma.conf.js - the config file for karma, which runs our tests.
+
+var webpack = require('webpack');
+var path = require('path');
+
+/*
+ * We use webpack to build our tests. It's a pain to have to wait for webpack
+ * to build everything; however it's the easiest way to load our dependencies
+ * from node_modules.
+ *
+ * TODO:
+ * - can we run one test at a time?
+ */
+
+process.env.PHANTOMJS_BIN = 'node_modules/.bin/phantomjs';
+
+module.exports = function (config) {
+    config.set({
+        // frameworks to use
+        // available frameworks: https://npmjs.org/browse/keyword/karma-adapter
+        frameworks: ['mocha'],
+
+        // list of files / patterns to load in the browser
+        files: [
+            'test/tests.js',
+        ],
+
+        // list of files to exclude
+        // (this doesn't work, and I don't know why - we still rerun the tests
+        // when lockfiles are created)
+        exclude: [
+            '**/.#*'
+        ],
+
+        // preprocess matching files before serving them to the browser
+        // available preprocessors:
+        // https://npmjs.org/browse/keyword/karma-preprocessor
+        preprocessors: {
+            'test/tests.js': ['webpack', 'sourcemap']
+        },
+
+        // test results reporter to use
+        // possible values: 'dots', 'progress'
+        // available reporters: https://npmjs.org/browse/keyword/karma-reporter
+        reporters: ['progress', 'junit'],
+
+        // 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_INFO,
+
+        // 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: [
+            'Chrome',
+            //'PhantomJS',
+        ],
+
+        // Continuous Integration mode
+        // if true, Karma captures browsers, runs the tests and exits
+        singleRun: true,
+
+        // Concurrency level
+        // how many browser should be started simultaneous
+        concurrency: Infinity,
+
+        junitReporter: {
+            outputDir: 'karma-reports',
+        },
+
+        webpack: {
+            module: {
+                loaders: [
+                    { test: /\.json$/, loader: "json" },
+                    {
+                        // disable 'require' and 'define' for sinon, per
+                        // https://github.com/webpack/webpack/issues/304#issuecomment-170883329
+                        test: /sinon\/pkg\/sinon\.js/,
+                        // TODO: use 'query'?
+                        loader: 'imports?define=>false,require=>false',
+                    },
+                    {
+                        test: /\.js$/, loader: "babel",
+                        include: [path.resolve('./src'),
+                                  path.resolve('./test'),
+                                 ],
+                        query: {
+                            presets: ['react', 'es2015']
+                        },
+                    },
+                ],
+                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'),
+                    'sinon': 'sinon/pkg/sinon.js',
+                },
+            },
+            devtool: 'inline-source-map',
+        },
+    });
+};
diff --git a/package.json b/package.json
index d2e9c32d74..c26289712c 100644
--- a/package.json
+++ b/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 --browsers PhantomJS",
+    "test-multi": "karma start --single-run=false"
   },
   "dependencies": {
     "classnames": "^2.1.2",
@@ -38,13 +40,31 @@
     "velocity-animate": "^1.2.3",
     "velocity-ui-pack": "^1.2.2"
   },
-  "//deps": "The loader packages are here because webpack in a project that depends on us needs them in this package's node_modules folder",
-  "//depsbuglink": "https://github.com/webpack/webpack/issues/1472",
   "devDependencies": {
     "babel": "^5.8.23",
+    "babel-core": "^6.7.4",
+    "babel-loader": "^6.2.4",
+    "babel-preset-es2015": "^6.6.0",
+    "babel-preset-react": "^6.5.0",
+    "babel-runtime": "^6.6.1",
+    "expect": "^1.16.0",
+    "imports-loader": "^0.6.5",
     "json-loader": "^0.5.3",
+    "karma": "^0.13.22",
+    "karma-chrome-launcher": "^0.2.3",
+    "karma-cli": "^0.1.2",
+    "karma-junit-reporter": "^0.4.1",
+    "karma-mocha": "^0.2.2",
+    "karma-phantomjs-launcher": "^1.0.0",
+    "karma-sourcemap-loader": "^0.3.7",
+    "karma-webpack": "^1.7.0",
+    "mocha": "^2.4.5",
+    "phantomjs-prebuilt": "^2.1.7",
+    "react-addons-test-utils": "^0.14.7",
     "require-json": "0.0.1",
     "rimraf": "^2.4.3",
-    "source-map-loader": "^0.1.5"
+    "sinon": "^1.17.3",
+    "source-map-loader": "^0.1.5",
+    "webpack": "^1.12.14"
   }
 }
diff --git a/test/components/structures/MatrixChat-test.js b/test/components/structures/MatrixChat-test.js
new file mode 100644
index 0000000000..7d96b3a77a
--- /dev/null
+++ b/test/components/structures/MatrixChat-test.js
@@ -0,0 +1,29 @@
+var React = require('react');
+var TestUtils = require('react-addons-test-utils');
+var expect = require('expect');
+
+var sdk = require('matrix-react-sdk');
+
+var test_utils = require('../../test-utils');
+var peg = require('../../../src/MatrixClientPeg.js');
+var q = require('q');
+
+describe('MatrixChat', function () {
+    var MatrixChat;
+    before(function() {
+        test_utils.stubClient();
+        MatrixChat = sdk.getComponent('structures.MatrixChat');
+    });
+    
+    it('gives a login panel by default', function () {
+        peg.get().loginFlows.returns(q({flows:[]}));
+
+        var res = TestUtils.renderIntoDocument(
+                <MatrixChat config={{}}/>
+        );
+
+        // we expect a single <Login> component
+        TestUtils.findRenderedComponentWithType(
+            res, sdk.getComponent('structures.login.Login'));
+    });
+});
diff --git a/test/components/stub-component.js b/test/components/stub-component.js
new file mode 100644
index 0000000000..8882a0b35d
--- /dev/null
+++ b/test/components/stub-component.js
@@ -0,0 +1,11 @@
+/* A dummy React component which we use for stubbing out app-level components
+ */
+'use strict';
+
+var React = require('react');
+
+module.exports = React.createClass({
+    render: function() {
+        return <div />;
+    },
+});
diff --git a/test/test-component-index.js b/test/test-component-index.js
new file mode 100644
index 0000000000..9b5c07af54
--- /dev/null
+++ b/test/test-component-index.js
@@ -0,0 +1,18 @@
+/*
+ * test-component-index.js
+ *
+ * Stub out a bunch of the components which we expect the application to
+ * provide
+ */
+var components = require('../src/component-index.js').components;
+var stub = require('./components/stub-component.js');
+
+components['structures.LeftPanel'] = stub;
+components['structures.RightPanel'] = stub;
+components['structures.RoomDirectory'] = stub;
+components['views.globals.MatrixToolbar'] = stub;
+components['views.globals.GuestWarningBar'] = stub;
+components['views.globals.NewVersionBar'] = stub;
+components['views.elements.Spinner'] = stub;
+
+module.exports.components = components;
diff --git a/test/test-utils.js b/test/test-utils.js
new file mode 100644
index 0000000000..7c0f38693a
--- /dev/null
+++ b/test/test-utils.js
@@ -0,0 +1,36 @@
+"use strict";
+
+var peg = require('../src/MatrixClientPeg.js');
+var jssdk = require('matrix-js-sdk');
+var sinon = require('sinon');
+
+/**
+ * Stub out the MatrixClient, and configure the MatrixClientPeg object to
+ * return it when get() is called.
+ */
+module.exports.stubClient = function() {
+    var pegstub = sinon.stub(peg);
+
+    var matrixClientStub = sinon.createStubInstance(jssdk.MatrixClient);
+    pegstub.get.returns(matrixClientStub);
+}
+
+
+/**
+ * make the test fail, with the given exception
+ *
+ * <p>This is useful for use with integration tests which use asyncronous
+ * methods: it can be added as a 'catch' handler in a promise chain.
+ *
+ * @param {Error} error   exception to be reported
+ *
+ * @example
+ * it("should not throw", function(done) {
+ *    asynchronousMethod().then(function() {
+ *       // some tests
+ *    }).catch(utils.failTest).done(done);
+ * });
+ */
+module.exports.failTest = function(error) {
+    expect(error.stack).toBe(null);
+};
diff --git a/test/tests.js b/test/tests.js
new file mode 100644
index 0000000000..3eec9ae8ee
--- /dev/null
+++ b/test/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('./test-component-index'));
+
+var context = require.context('.', true, /-test\.jsx?$/);
+context.keys().forEach(context);