From 3f545e870e8d96aedb0f9be4e1c5c6b9f5ea4a0f Mon Sep 17 00:00:00 2001
From: David Ortner <david@ortner.se>
Date: Thu, 9 Jan 2025 00:32:16 +0100
Subject: [PATCH] chore: [#1678] Fixes problem with query selector

---
 .../happy-dom/src/query-selector/SelectorItem.ts   |  4 +++-
 .../happy-dom/test/html-parser/HTMLParser.test.ts  |  4 ++++
 .../test/query-selector/QuerySelector.test.ts      | 14 ++++++++++++--
 3 files changed, 19 insertions(+), 3 deletions(-)

diff --git a/packages/happy-dom/src/query-selector/SelectorItem.ts b/packages/happy-dom/src/query-selector/SelectorItem.ts
index d27063ff8..0bf5b4c5a 100644
--- a/packages/happy-dom/src/query-selector/SelectorItem.ts
+++ b/packages/happy-dom/src/query-selector/SelectorItem.ts
@@ -7,6 +7,8 @@ import ISelectorAttribute from './ISelectorAttribute.js';
 import ISelectorMatch from './ISelectorMatch.js';
 import ISelectorPseudo from './ISelectorPseudo.js';
 
+const SPACE_REGEXP = /\s+/;
+
 /**
  * Selector item.
  */
@@ -417,7 +419,7 @@ export default class SelectorItem {
 			return null;
 		}
 
-		const classList = element.className.split(' ');
+		const classList = element.className.split(SPACE_REGEXP);
 		let priorityWeight = 0;
 
 		for (const className of this.classNames) {
diff --git a/packages/happy-dom/test/html-parser/HTMLParser.test.ts b/packages/happy-dom/test/html-parser/HTMLParser.test.ts
index b099649b2..a260b1975 100644
--- a/packages/happy-dom/test/html-parser/HTMLParser.test.ts
+++ b/packages/happy-dom/test/html-parser/HTMLParser.test.ts
@@ -2137,6 +2137,10 @@ describe('HTMLParser', () => {
                  visually-hidden" type="button">{{message_gui_replies}}</button>
             </div>`
 			);
+
+			const element = result.querySelector('div > .comment_collapse');
+
+			expect(element).toBe(result.children[0].children[1]);
 		});
 	});
 });
diff --git a/packages/happy-dom/test/query-selector/QuerySelector.test.ts b/packages/happy-dom/test/query-selector/QuerySelector.test.ts
index a72324b56..7e4f9ea8b 100644
--- a/packages/happy-dom/test/query-selector/QuerySelector.test.ts
+++ b/packages/happy-dom/test/query-selector/QuerySelector.test.ts
@@ -18,7 +18,7 @@ describe('QuerySelector', () => {
 		document = window.document;
 	});
 
-	describe('querySelectorAll', () => {
+	describe('querySelectorAll()', () => {
 		it('Throws an error for invalid selectors.', () => {
 			const container = document.createElement('div');
 			expect(() => container.querySelectorAll(<string>(<unknown>12))).toThrow(
@@ -1214,7 +1214,7 @@ describe('QuerySelector', () => {
 		});
 	});
 
-	describe('querySelector', () => {
+	describe('querySelector()', () => {
 		it('Throws an error for invalid selectors.', () => {
 			const container = document.createElement('div');
 			expect(() => container.querySelector(<string>(<unknown>12))).toThrow(
@@ -1628,6 +1628,16 @@ describe('QuerySelector', () => {
 			expect(document.querySelector(':focus')).toBe(div);
 			expect(document.querySelector(':focus-visible')).toBe(div);
 		});
+
+		it('Handles class names with line breaks', () => {
+			const div = document.createElement('div');
+			div.innerHTML = `
+                <div class="class1
+                class2"></div>
+            `;
+
+			expect(div.querySelector('.class1.class2')).toBe(div.children[0]);
+		});
 	});
 
 	describe('matches()', () => {