diff --git a/.travis.yml b/.travis.yml
index 26976b9cd7..e2248505c0 100644
--- a/.travis.yml
+++ b/.travis.yml
@@ -85,10 +85,11 @@ jobs:
 
 notifications:
   email: false
-  urls:
-    # for gitter mochajs/mocha
-    - secure: fUrHenYJs+pTuLtgBRoYyrlyfVekxaIGmLWq7bhUUqBj/7p5eCkQFn13LlPht0/4WWZOiPBcdTN7tKnz3Ho7ATUJhAchvOWDUgL5gtTvOzeCHbPuCvHz/VLK6hMoPdbLA45M864NDLotfHvyh62WgQaVw9iPc80eb+umaDPrYiU=
-    # for gitter mochajs/contributors
-    - secure: rGMGYWBaZgEa9i997jJHKzjI8WxECqLi6BqsMhvstDq9EeTeXkZFVfz4r6G3Xugsk3tFwb/pDpiYo1OK36kA5arUJTCia51u4Wn+c7lHKcpef/vXztoyucvw6/jXdVm/FQz1jztYYbqdyAOWC2BV8gYvg5F8TpK05UGCe5R0bRA=
-  on_success: change
-  on_failure: always
+  webhooks:
+    urls:
+      # for gitter mochajs/mocha
+      - secure: fUrHenYJs+pTuLtgBRoYyrlyfVekxaIGmLWq7bhUUqBj/7p5eCkQFn13LlPht0/4WWZOiPBcdTN7tKnz3Ho7ATUJhAchvOWDUgL5gtTvOzeCHbPuCvHz/VLK6hMoPdbLA45M864NDLotfHvyh62WgQaVw9iPc80eb+umaDPrYiU=
+      # for gitter mochajs/contributors
+      - secure: rGMGYWBaZgEa9i997jJHKzjI8WxECqLi6BqsMhvstDq9EeTeXkZFVfz4r6G3Xugsk3tFwb/pDpiYo1OK36kA5arUJTCia51u4Wn+c7lHKcpef/vXztoyucvw6/jXdVm/FQz1jztYYbqdyAOWC2BV8gYvg5F8TpK05UGCe5R0bRA=
+    on_success: change
+    on_failure: always
diff --git a/karma.conf.js b/karma.conf.js
index ae84d7d830..53ad6d4313 100644
--- a/karma.conf.js
+++ b/karma.conf.js
@@ -38,6 +38,10 @@ module.exports = config => {
           .ignore('./lib/esm-utils.js')
           .ignore('path')
           .ignore('supports-color')
+          .ignore('./lib/buffered-runner.js')
+          .ignore('./lib/reporters/buffered.js')
+          .ignore('./lib/serializer.js')
+          .ignore('./lib/worker.js')
           .on('bundled', (err, content) => {
             if (err) {
               throw err;
diff --git a/package-scripts.js b/package-scripts.js
index 9c68e3a915..fe4395aed4 100644
--- a/package-scripts.js
+++ b/package-scripts.js
@@ -23,7 +23,7 @@ function test(testName, mochaParams) {
 module.exports = {
   scripts: {
     build: {
-      script: `browserify -e browser-entry.js --plugin ./scripts/dedefine --ignore './lib/cli/*.js' --ignore "./lib/esm-utils.js" --ignore 'chokidar' --ignore 'fs' --ignore 'glob' --ignore 'path' --ignore 'supports-color' --ignore './lib/buffered-runner.js' --ignore './lib/serializer.js' --ignore './lib/reporters/buffered.js' -o mocha.js`,
+      script: `browserify -e browser-entry.js --plugin ./scripts/dedefine --ignore './lib/cli/*.js' --ignore "./lib/esm-utils.js" --ignore 'chokidar' --ignore 'fs' --ignore 'glob' --ignore 'path' --ignore 'supports-color' --ignore './lib/buffered-runner.js' --ignore './lib/serializer.js' --ignore './lib/reporters/buffered.js' --ignore './lib/worker.js' -o mocha.js`,
       description: 'Build browser bundle'
     },
     lint: {
diff --git a/package.json b/package.json
index f0ce5226e1..87635115b1 100644
--- a/package.json
+++ b/package.json
@@ -157,7 +157,8 @@
     "supports-color": false,
     "./lib/serializer.js": false,
     "./lib/reporters/buffered.js": false,
-    "./lib/buffered-reporter.js": false
+    "./lib/buffered-reporter.js": false,
+    "./lib/worker.js": false
   },
   "prettier": {
     "singleQuote": true,