diff --git a/eslint.config.mjs b/eslint.config.mjs
index 13b1a32a..f6050b14 100644
--- a/eslint.config.mjs
+++ b/eslint.config.mjs
@@ -78,8 +78,6 @@ export default [
             globals: {
                 ...globals.node,
                 ...globals.mocha,
-                sinon: false,
-                expect: false,
             }
         },
         rules: {
diff --git a/tests/assertions.js b/tests/assertions.js
index a7012271..ea0003b6 100644
--- a/tests/assertions.js
+++ b/tests/assertions.js
@@ -1,10 +1,6 @@
 import * as chai from '../node_modules/chai/chai.js';
-import sinon from '../node_modules/sinon/pkg/sinon-esm.js';
 import sinonChai from '../node_modules/sinon-chai/lib/sinon-chai.js';
 
-window.expect = chai.expect;
-
-window.sinon = sinon;
 chai.use(sinonChai);
 
 // noVNC specific assertions
diff --git a/tests/test.base64.js b/tests/test.base64.js
index e5644dcd..120608e3 100644
--- a/tests/test.base64.js
+++ b/tests/test.base64.js
@@ -1,3 +1,5 @@
+import { expect } from '../node_modules/chai/chai.js';
+
 import Base64 from '../core/base64.js';
 
 describe('Base64 Tools', function () {
diff --git a/tests/test.browser.js b/tests/test.browser.js
index 692cc23b..fa82e7bc 100644
--- a/tests/test.browser.js
+++ b/tests/test.browser.js
@@ -1,3 +1,5 @@
+import { expect } from '../node_modules/chai/chai.js';
+
 import { isMac, isWindows, isIOS, isAndroid, isChromeOS,
          isSafari, isFirefox, isChrome, isChromium, isOpera, isEdge,
          isGecko, isWebKit, isBlink } from '../core/util/browser.js';
diff --git a/tests/test.copyrect.js b/tests/test.copyrect.js
index 60c39528..82a9bf36 100644
--- a/tests/test.copyrect.js
+++ b/tests/test.copyrect.js
@@ -1,3 +1,5 @@
+import { expect } from '../node_modules/chai/chai.js';
+
 import Websock from '../core/websock.js';
 import Display from '../core/display.js';
 
diff --git a/tests/test.deflator.js b/tests/test.deflator.js
index b565b907..2da03823 100644
--- a/tests/test.deflator.js
+++ b/tests/test.deflator.js
@@ -1,3 +1,5 @@
+import { expect } from '../node_modules/chai/chai.js';
+
 import { inflateInit, inflate } from "../vendor/pako/lib/zlib/inflate.js";
 import ZStream from "../vendor/pako/lib/zlib/zstream.js";
 import Deflator from "../core/deflator.js";
diff --git a/tests/test.display.js b/tests/test.display.js
index d2c51793..48e90a43 100644
--- a/tests/test.display.js
+++ b/tests/test.display.js
@@ -1,3 +1,6 @@
+import { expect } from '../node_modules/chai/chai.js';
+import sinon from '../node_modules/sinon/pkg/sinon-esm.js';
+
 import Base64 from '../core/base64.js';
 import Display from '../core/display.js';
 
diff --git a/tests/test.gesturehandler.js b/tests/test.gesturehandler.js
index d2e27ed2..e3c2e32a 100644
--- a/tests/test.gesturehandler.js
+++ b/tests/test.gesturehandler.js
@@ -1,3 +1,6 @@
+import { expect } from '../node_modules/chai/chai.js';
+import sinon from '../node_modules/sinon/pkg/sinon-esm.js';
+
 import EventTargetMixin from '../core/util/eventtarget.js';
 
 import GestureHandler from '../core/input/gesturehandler.js';
diff --git a/tests/test.helper.js b/tests/test.helper.js
index 2c8720c7..04428dd1 100644
--- a/tests/test.helper.js
+++ b/tests/test.helper.js
@@ -1,3 +1,5 @@
+import { expect } from '../node_modules/chai/chai.js';
+
 import keysyms from '../core/input/keysymdef.js';
 import * as KeyboardUtil from "../core/input/util.js";
 
diff --git a/tests/test.hextile.js b/tests/test.hextile.js
index f788fd4d..3fea3023 100644
--- a/tests/test.hextile.js
+++ b/tests/test.hextile.js
@@ -1,3 +1,5 @@
+import { expect } from '../node_modules/chai/chai.js';
+
 import Websock from '../core/websock.js';
 import Display from '../core/display.js';
 
diff --git a/tests/test.inflator.js b/tests/test.inflator.js
index 11a02f2f..8bf4f6f3 100644
--- a/tests/test.inflator.js
+++ b/tests/test.inflator.js
@@ -1,3 +1,5 @@
+import { expect } from '../node_modules/chai/chai.js';
+
 import { deflateInit, deflate, Z_FULL_FLUSH } from "../vendor/pako/lib/zlib/deflate.js";
 import ZStream from "../vendor/pako/lib/zlib/zstream.js";
 import Inflator from "../core/inflator.js";
diff --git a/tests/test.int.js b/tests/test.int.js
index 378ebd58..641d9db6 100644
--- a/tests/test.int.js
+++ b/tests/test.int.js
@@ -1,3 +1,5 @@
+import { expect } from '../node_modules/chai/chai.js';
+
 import { toUnsigned32bit, toSigned32bit } from '../core/util/int.js';
 
 describe('Integer casting', function () {
diff --git a/tests/test.jpeg.js b/tests/test.jpeg.js
index 5cc153f9..4340242f 100644
--- a/tests/test.jpeg.js
+++ b/tests/test.jpeg.js
@@ -1,3 +1,5 @@
+import { expect } from '../node_modules/chai/chai.js';
+
 import Websock from '../core/websock.js';
 import Display from '../core/display.js';
 
diff --git a/tests/test.keyboard.js b/tests/test.keyboard.js
index 11c8b6eb..4296486f 100644
--- a/tests/test.keyboard.js
+++ b/tests/test.keyboard.js
@@ -1,3 +1,6 @@
+import { expect } from '../node_modules/chai/chai.js';
+import sinon from '../node_modules/sinon/pkg/sinon-esm.js';
+
 import Keyboard from '../core/input/keyboard.js';
 
 describe('Key Event Handling', function () {
diff --git a/tests/test.localization.js b/tests/test.localization.js
index a1cb4547..e49a0735 100644
--- a/tests/test.localization.js
+++ b/tests/test.localization.js
@@ -1,3 +1,6 @@
+import { expect } from '../node_modules/chai/chai.js';
+import sinon from '../node_modules/sinon/pkg/sinon-esm.js';
+
 import _, { Localizer, l10n } from '../app/localization.js';
 
 describe('Localization', function () {
diff --git a/tests/test.raw.js b/tests/test.raw.js
index 19b2377f..e3d8b457 100644
--- a/tests/test.raw.js
+++ b/tests/test.raw.js
@@ -1,3 +1,5 @@
+import { expect } from '../node_modules/chai/chai.js';
+
 import Websock from '../core/websock.js';
 import Display from '../core/display.js';
 
diff --git a/tests/test.rfb.js b/tests/test.rfb.js
index 2be3bfbf..b4d59e02 100644
--- a/tests/test.rfb.js
+++ b/tests/test.rfb.js
@@ -1,3 +1,6 @@
+import { expect } from '../node_modules/chai/chai.js';
+import sinon from '../node_modules/sinon/pkg/sinon-esm.js';
+
 import RFB from '../core/rfb.js';
 import Websock from '../core/websock.js';
 import ZStream from "../vendor/pako/lib/zlib/zstream.js";
diff --git a/tests/test.rre.js b/tests/test.rre.js
index 7b5f73d0..5ca0d732 100644
--- a/tests/test.rre.js
+++ b/tests/test.rre.js
@@ -1,3 +1,5 @@
+import { expect } from '../node_modules/chai/chai.js';
+
 import Websock from '../core/websock.js';
 import Display from '../core/display.js';
 
diff --git a/tests/test.tight.js b/tests/test.tight.js
index 3d6b555d..28080bf4 100644
--- a/tests/test.tight.js
+++ b/tests/test.tight.js
@@ -1,3 +1,5 @@
+import { expect } from '../node_modules/chai/chai.js';
+
 import Websock from '../core/websock.js';
 import Display from '../core/display.js';
 
diff --git a/tests/test.tightpng.js b/tests/test.tightpng.js
index e7edc8fa..01d2493e 100644
--- a/tests/test.tightpng.js
+++ b/tests/test.tightpng.js
@@ -1,3 +1,5 @@
+import { expect } from '../node_modules/chai/chai.js';
+
 import Websock from '../core/websock.js';
 import Display from '../core/display.js';
 
diff --git a/tests/test.util.js b/tests/test.util.js
index eb724095..16dbb7c9 100644
--- a/tests/test.util.js
+++ b/tests/test.util.js
@@ -1,4 +1,7 @@
 /* eslint-disable no-console */
+import { expect } from '../node_modules/chai/chai.js';
+import sinon from '../node_modules/sinon/pkg/sinon-esm.js';
+
 import * as Log from '../core/util/logging.js';
 import { encodeUTF8, decodeUTF8 } from '../core/util/strings.js';
 
diff --git a/tests/test.websock.js b/tests/test.websock.js
index 53145b36..38b654a8 100644
--- a/tests/test.websock.js
+++ b/tests/test.websock.js
@@ -1,3 +1,6 @@
+import { expect } from '../node_modules/chai/chai.js';
+import sinon from '../node_modules/sinon/pkg/sinon-esm.js';
+
 import Websock from '../core/websock.js';
 import FakeWebSocket from './fake.websocket.js';
 
diff --git a/tests/test.webutil.js b/tests/test.webutil.js
index 9151a060..45c71e49 100644
--- a/tests/test.webutil.js
+++ b/tests/test.webutil.js
@@ -1,5 +1,8 @@
 /* jshint expr: true */
 
+import { expect } from '../node_modules/chai/chai.js';
+import sinon from '../node_modules/sinon/pkg/sinon-esm.js';
+
 import * as WebUtil from '../app/webutil.js';
 
 describe('WebUtil', function () {
diff --git a/tests/test.zrle.js b/tests/test.zrle.js
index f7c6089d..679b4ad3 100644
--- a/tests/test.zrle.js
+++ b/tests/test.zrle.js
@@ -1,3 +1,5 @@
+import { expect } from '../node_modules/chai/chai.js';
+
 import Websock from '../core/websock.js';
 import Display from '../core/display.js';