packages/jest-environment/src/index.ts

@@ -68,6 +68,8 @@ export default class HappyDOMEnvironment implements JestEnvironment {
 
 		if (projectConfig.testEnvironmentOptions['url']) {
 			this.window.happyDOM.setURL(String(projectConfig.testEnvironmentOptions['url']));
+		} else {
+			this.window.happyDOM.setURL('http://localhost/');
 		}
 
 		this.fakeTimers = new LegacyFakeTimers({

packages/jest-environment/test/javascript/JavaScript.test.ts

@@ -9,6 +9,10 @@ describe('JavaScript', () => {
 		expect({}.constructor).toBe(Object);
 	});
 
+	it('Document.location.href should be "http://localhost/", which is the default for the JSDOM Jest environment', () => {
+		expect(document.location.href).toBe('http://localhost/');
+	});
+
 	it('Can perform a real fetch()', async () => {
 		const express = Express();