diff --git a/karma.conf.js b/karma.conf.js
index abd53f6afb..7a866d902d 100644
--- a/karma.conf.js
+++ b/karma.conf.js
@@ -7,7 +7,6 @@ var path = require('path');
  * the easiest way to load our dependencies from node_modules.
  *
  * TODO:
- * - how do we stub out the js-sdk
  * - can we run one test at a time
  * - can we can we run under phantomjs/jsdom?
  * - write junit out
@@ -20,7 +19,14 @@ module.exports = function (config) {
 
         // list of files / patterns to load in the browser
         files: [
-            'test/tests.js'
+            '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
@@ -70,13 +76,21 @@ module.exports = function (config) {
             module: {
                 loaders: [
                     { test: /\.json$/, loader: "json" },
-                    { test: /\.js$/, loader: "babel",
-                      include: [path.resolve('./src'),
-                                path.resolve('./test'),
-                               ],
-                      query: {
-                          presets: ['react', 'es2015']
-                      },
+                    {
+                        // 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: [
@@ -91,6 +105,7 @@ module.exports = function (config) {
             resolve: {
                 alias: {
                     'matrix-react-sdk': path.resolve('src/index.js'),
+                    'sinon': 'sinon/pkg/sinon.js',
                 },
             },
             devtool: 'inline-source-map',
diff --git a/test/components/structures/MatrixChat-test.js b/test/components/structures/MatrixChat-test.js
index 4d5c368873..46c76bb007 100644
--- a/test/components/structures/MatrixChat-test.js
+++ b/test/components/structures/MatrixChat-test.js
@@ -3,14 +3,21 @@ var TestUtils = require('react-addons-test-utils');
 var expect = require('expect');
 
 var sdk = require('matrix-react-sdk');
-var MatrixChat;
+
+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({}));
+
         var res = TestUtils.renderIntoDocument(
                 <MatrixChat config={{}}/>
         );
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);
+};