diff --git a/.eslintignore.errorfiles b/.eslintignore.errorfiles
index 4584d7ed65..ffd492d491 100644
--- a/.eslintignore.errorfiles
+++ b/.eslintignore.errorfiles
@@ -146,7 +146,6 @@ src/Roles.js
 src/RoomListSorter.js
 src/RoomNotifs.js
 src/Rooms.js
-src/RtsClient.js
 src/ScalarAuthClient.js
 src/ScalarMessaging.js
 src/SdkConfig.js
diff --git a/src/Lifecycle.js b/src/Lifecycle.js
index 338341f403..39a159869c 100644
--- a/src/Lifecycle.js
+++ b/src/Lifecycle.js
@@ -265,7 +265,11 @@ function _handleRestoreFailure(e) {
 
 let rtsClient = null;
 export function initRtsClient(url) {
-    rtsClient = new RtsClient(url);
+    if (url) {
+        rtsClient = new RtsClient(url);
+    } else {
+        rtsClient = null;
+    }
 }
 
 /**
diff --git a/src/RtsClient.js b/src/RtsClient.js
index 8c3ce54b37..493b19599c 100644
--- a/src/RtsClient.js
+++ b/src/RtsClient.js
@@ -1,5 +1,7 @@
 import 'whatwg-fetch';
 
+let fetchFunction = fetch;
+
 function checkStatus(response) {
     if (!response.ok) {
         return response.text().then((text) => {
@@ -31,7 +33,7 @@ const request = (url, opts) => {
         opts.body = JSON.stringify(opts.body);
         opts.headers['Content-Type'] = 'application/json';
     }
-    return fetch(url, opts)
+    return fetchFunction(url, opts)
         .then(checkStatus)
         .then(parseJson);
 };
@@ -64,7 +66,7 @@ export default class RtsClient {
                     client_secret: clientSecret,
                 },
                 method: 'POST',
-            }
+            },
         );
     }
 
@@ -74,7 +76,7 @@ export default class RtsClient {
                 qs: {
                     team_token: teamToken,
                 },
-            }
+            },
         );
     }
 
@@ -91,7 +93,12 @@ export default class RtsClient {
                 qs: {
                     user_id: userId,
                 },
-            }
+            },
         );
     }
+
+    // allow fetch to be replaced, for testing.
+    static setFetch(fn) {
+        fetchFunction = fn;
+    }
 }
diff --git a/src/components/structures/MatrixChat.js b/src/components/structures/MatrixChat.js
index ed1cd183a7..efca22cc85 100644
--- a/src/components/structures/MatrixChat.js
+++ b/src/components/structures/MatrixChat.js
@@ -263,11 +263,8 @@ module.exports = React.createClass({
         window.addEventListener('resize', this.handleResize);
         this.handleResize();
 
-        if (this.props.config.teamServerConfig &&
-            this.props.config.teamServerConfig.teamServerURL
-        ) {
-            Lifecycle.initRtsClient(this.props.config.teamServerConfig.teamServerURL);
-        }
+        const teamServerConfig = this.props.config.teamServerConfig || {};
+        Lifecycle.initRtsClient(teamServerConfig.teamServerURL);
 
         // if the user has followed a login or register link, don't reanimate
         // the old creds, but rather go straight to the relevant page
diff --git a/src/index.js b/src/index.js
index 7d0547d9c9..8c290fcb64 100644
--- a/src/index.js
+++ b/src/index.js
@@ -15,6 +15,7 @@ limitations under the License.
 */
 
 import Skinner from './Skinner';
+import RtsClient from './RtsClient';
 
 module.exports.loadSkin = function(skinObject) {
     Skinner.load(skinObject);
@@ -27,3 +28,7 @@ module.exports.resetSkin = function() {
 module.exports.getComponent = function(componentName) {
     return Skinner.getComponent(componentName);
 };
+
+module.exports.setFetch = function(fetchFunction) {
+    RtsClient.setFetch(fetchFunction);
+};