diff --git a/.travis.yml b/.travis.yml
index 24de51984a..74212c2c27 100644
--- a/.travis.yml
+++ b/.travis.yml
@@ -5,6 +5,9 @@ language: node_js
 node_js:
   - "6.1"
 
+addons:
+  firefox: "latest"
+
 cache:
   directories:
     - node_modules
diff --git a/package.json b/package.json
index b1c43da1f3..05121e2569 100644
--- a/package.json
+++ b/package.json
@@ -69,7 +69,7 @@
     "resemblejs": "2.2.3",
     "serve-files": "1.0.1",
     "sinon": "2.0.0",
-    "slimerjs": "0.906.2"
+    "slimerjs": "0.10.3"
   },
   "eslintConfig": {
     "extends": "openlayers",
diff --git a/tasks/test-rendering.js b/tasks/test-rendering.js
index df720de2a9..f9384bacfc 100644
--- a/tasks/test-rendering.js
+++ b/tasks/test-rendering.js
@@ -38,23 +38,12 @@ serve.createServer(function(err, server) {
       url + '/test_rendering/index.html'
     ];
 
-    // TODO
-    // Workaround for https://github.com/laurentj/slimerjs/issues/333. When a
-    // version with the fix is released, replace block below with:
-    // var child = spawn(slimerjs.path, args, {stdio: 'pipe'});
-    // child.on('exit', function(code) {
-    //   process.exit(code);
-    // }
-
     var child = spawn(slimerjs.path, args, {stdio: 'pipe'});
     child.stdout.on('data', function(data) {
       process.stdout.write(data);
-      if (data == 'All tests passed.\n') {
-        process.exit(0);
-      }
     });
-    child.on('exit', function() {
-      process.exit(1);
+    child.on('exit', function(code) {
+      process.exit(code);
     });
   });
 
diff --git a/test_rendering/spec/ol/layer/vectortile.test.js b/test_rendering/spec/ol/layer/vectortile.test.js
index f7e050818d..f4224e9cb5 100644
--- a/test_rendering/spec/ol/layer/vectortile.test.js
+++ b/test_rendering/spec/ol/layer/vectortile.test.js
@@ -76,7 +76,7 @@ describe('ol.rendering.layer.VectorTile', function() {
       map = createMap('canvas');
       waitForTiles(source, {}, function() {
         expectResemble(map, 'spec/ol/layer/expected/vectortile-canvas.png',
-            11.6, done);
+            11.7, done);
       });
     });