feat(editor): Migrate codemirror-lang-n8n-expression into this monorepo (no-changelog) (#9087)

Co-authored-by: Iván Ovejero <ivov.src@gmail.com>

packages/@n8n/codemirror-lang/test/expressions/expressions.test.ts

@@ -0,0 +1,21 @@
+import fs from 'fs';
+import path from 'path';
+import { fileTests as runTestFile } from '@lezer/generator/dist/test';
+import { n8nLanguage } from '../../src/expressions/index';
+
+describe('expressions language', () => {
+	const CASES_DIR = __dirname;
+	for (const testFile of fs.readdirSync(CASES_DIR)) {
+		if (!/\.txt$/.test(testFile)) continue;
+
+		const testFileName = /^[^\.]*/.exec(testFile)![0];
+		describe(testFileName, () => {
+			for (const { name, run } of runTestFile(
+				fs.readFileSync(path.join(CASES_DIR, testFile), 'utf8'),
+				testFile,
+			)) {
+				it(name, () => run(n8nLanguage.parser));
+			}
+		});
+	}
+});