Move sinon to karma framework

This frees us from manual imports, and makes things less magical
as those aren't ES modules even if the code suggest that the are.

tests/.eslintrc

@@ -4,9 +4,10 @@
         "mocha": true
     },
     "globals": {
-        "chai": true
+        "chai": false,
+        "sinon": false
     },
     "rules": {
         "prefer-arrow-callback": 0
     }
-}
+}

tests/assertions.js

@@ -1,7 +1,3 @@
-// Assertions that make it easier to use sinon
-import sinonChai from '../node_modules/sinon-chai/lib/sinon-chai.js';
-chai.use(sinonChai);
-
 // noVNC specific assertions
 chai.use(function (_chai, utils) {
     _chai.Assertion.addMethod('displayed', function (target_data) {

tests/test.display.js

@@ -3,8 +3,6 @@ const expect = chai.expect;
 import Base64 from '../core/base64.js';
 import Display from '../core/display.js';
 
-import sinon from '../vendor/sinon.js';
-
 describe('Display/Canvas Helper', function () {
     const checked_data = new Uint8Array([
         0x00, 0x00, 0xff, 255, 0x00, 0x00, 0xff, 255, 0x00, 0xff, 0x00, 255, 0x00, 0xff, 0x00, 255,

tests/test.keyboard.js

@@ -1,7 +1,5 @@
 const expect = chai.expect;
 
-import sinon from '../vendor/sinon.js';
-
 import Keyboard from '../core/input/keyboard.js';
 import * as browser from '../core/util/browser.js';
 

tests/test.mouse.js

@@ -1,7 +1,5 @@
 const expect = chai.expect;
 
-import sinon from '../vendor/sinon.js';
-
 import Mouse from '../core/input/mouse.js';
 import * as eventUtils from '../core/util/events.js';
 

tests/test.rfb.js

@@ -5,7 +5,6 @@ import Websock from '../core/websock.js';
 import { encodings } from '../core/encodings.js';
 
 import FakeWebSocket from './fake.websocket.js';
-import sinon from '../vendor/sinon.js';
 
 /* UIEvent constructor polyfill for IE */
 (() => {

tests/test.util.js

@@ -3,8 +3,6 @@ const expect = chai.expect;
 
 import * as Log from '../core/util/logging.js';
 
-import sinon from '../vendor/sinon.js';
-
 describe('Utils', function() {
     "use strict";
 

tests/test.websock.js

@@ -3,8 +3,6 @@ const expect = chai.expect;
 import Websock from '../core/websock.js';
 import FakeWebSocket from './fake.websocket.js';
 
-import sinon from '../vendor/sinon.js';
-
 describe('Websock', function() {
     "use strict";
 

tests/test.webutil.js

@@ -4,8 +4,6 @@ const expect = chai.expect;
 
 import * as WebUtil from '../app/webutil.js';
 
-import sinon from '../vendor/sinon.js';
-
 describe('WebUtil', function() {
     "use strict";