Unit tests: mock matchMedia to enforce prefers-reduce-motion (#65438)

* Add global matchMedia mock for prefers-reduced-motion

* Update DotTip snapshots

---

Co-authored-by: ciampo <mciampini@git.wordpress.org>
Co-authored-by: tyxla <tyxla@git.wordpress.org>

packages/nux/src/components/dot-tip/test/__snapshots__/index.js.snap

@@ -7,7 +7,7 @@ exports[`DotTip should render correctly 1`] = `
   data-wp-c16t="true"
   data-wp-component="Popover"
   role="dialog"
-  style="position: absolute; top: 0px; left: 0px; opacity: 1; transform: translateX(0px) translateY(0px) translateX(0em) scale(1) translateZ(0); transform-origin: 0% 50% 0;"
+  style="position: absolute; top: 0px; left: 0px; transform: none;"
   tabindex="-1"
 >
   <div

test/unit/jest.config.js

@@ -19,7 +19,10 @@ module.exports = {
 		'<rootDir>/test/unit/config/global-mocks.js',
 		'<rootDir>/test/unit/config/gutenberg-env.js',
 	],
-	setupFilesAfterEnv: [ '<rootDir>/test/unit/config/testing-library.js' ],
+	setupFilesAfterEnv: [
+		'<rootDir>/test/unit/config/testing-library.js',
+		'<rootDir>/test/unit/mocks/match-media.js',
+	],
 	testEnvironmentOptions: {
 		url: 'http://localhost/',
 	},

test/unit/mocks/match-media.js

@@ -0,0 +1,22 @@
+// Mock `matchMedia` so that all animations are skipped,
+// since js-dom does not fully support CSS animations.
+// Example: https://github.com/jsdom/jsdom/issues/3239
+const originalMatchMedia = window.matchMedia;
+const mockedMatchMedia = jest.fn( ( query ) => {
+	if ( /prefers-reduced-motion/.test( query ) ) {
+		return {
+			...originalMatchMedia( query ),
+			matches: true,
+		};
+	}
+
+	return originalMatchMedia( query );
+} );
+
+beforeAll( () => {
+	window.matchMedia = jest.fn( mockedMatchMedia );
+} );
+
+afterAll( () => {
+	window.matchMedia = originalMatchMedia;
+} );