feat: Add testcontainers and Playwright (no-changelog) (#16662)

Co-authored-by: Tomi Turtiainen <10324676+tomi@users.noreply.github.com>

packages/testing/playwright/utils/path-helper.ts

@@ -0,0 +1,32 @@
+import * as fs from 'fs';
+import * as path from 'path';
+
+import { TestError } from '../Types';
+
+/**
+ * Finds the project root by searching upwards for a marker file.
+ * @param marker The file that identifies the project root (e.g., 'playwright.config.ts' or 'package.json').
+ * @returns The absolute path to the project root.
+ */
+function findProjectRoot(marker: string): string {
+	let dir = __dirname;
+	while (!fs.existsSync(path.join(dir, marker))) {
+		const parentDir = path.dirname(dir);
+		if (parentDir === dir) {
+			throw new TestError('Could not find project root');
+		}
+		dir = parentDir;
+	}
+	return dir;
+}
+
+const playwrightRoot = findProjectRoot('playwright.config.ts');
+
+/**
+ * Resolves a path relative to the Playwright project root.
+ * @param pathSegments Segments of the path starting from the project root.
+ * @returns An absolute path to the file or directory.
+ */
+export function resolveFromRoot(...pathSegments: string[]): string {
+	return path.join(playwrightRoot, ...pathSegments);
+}