fix unclosed block detection

add parser tests (codex)

test/parser.test.js

@@ -0,0 +1,48 @@
+const assert = require('node:assert/strict');
+const test = require('node:test');
+
+const { EftlParser } = require('../out/parser');
+const { EftlTokenizer } = require('../out/tokenizer');
+
+function parse(source) {
+    const { tokens, errors: tokenizerErrors } = new EftlTokenizer(source).tokenize();
+    assert.deepEqual(tokenizerErrors, []);
+    return new EftlParser(tokens).parse().errors;
+}
+
+test('accepts a correctly closed VAR tag', () => {
+    assert.deepEqual(parse('[VAR][/VAR]'), []);
+});
+
+test('reports a VAR tag without its closing tag', () => {
+    assert.deepEqual(parse('[VAR]'), [{
+        message: 'Unclosed tag: [VAR] (expected [/VAR])',
+        line: 1,
+        column: 1,
+        length: 5
+    }]);
+});
+
+test('reports an unexpected closing tag', () => {
+    const errors = parse('[/VAR]');
+
+    assert.equal(errors.length, 1);
+    assert.match(errors[0].message, /Unexpected closing tag/);
+});
+
+test('reports every unclosed nested tag at its opening token', () => {
+    assert.deepEqual(parse('[EFTL]\n[VAR]'), [
+        {
+            message: 'Unclosed tag: [EFTL] (expected [/EFTL])',
+            line: 1,
+            column: 1,
+            length: 6
+        },
+        {
+            message: 'Unclosed tag: [VAR] (expected [/VAR])',
+            line: 2,
+            column: 1,
+            length: 5
+        }
+    ]);
+});