add explicit button type regression test

tests/button-types.test.mjs

@@ -0,0 +1,32 @@
+import test from 'node:test';
+import assert from 'node:assert/strict';
+import { readdir, readFile } from 'node:fs/promises';
+import { join } from 'node:path';
+
+const root = new URL('../src/', import.meta.url);
+
+async function jsxFiles(directory) {
+  const entries = await readdir(directory, { withFileTypes: true });
+  const files = [];
+  for (const entry of entries) {
+    const path = join(directory, entry.name);
+    if (entry.isDirectory()) files.push(...await jsxFiles(path));
+    else if (entry.isFile() && entry.name.endsWith('.jsx')) files.push(path);
+  }
+  return files;
+}
+
+test('every JSX button declares an explicit button or submit type', async () => {
+  const files = await jsxFiles(root.pathname);
+  const violations = [];
+  for (const file of files) {
+    const source = await readFile(file, 'utf8');
+    for (const match of source.matchAll(/<button\b[^>]*>/gs)) {
+      const tag = match[0];
+      const line = source.slice(0, match.index).split('\n').length;
+      const type = /\btype\s*=\s*["'](button|submit)["']/.exec(tag)?.[1];
+      if (!type) violations.push(`${file}:${line}`);
+    }
+  }
+  assert.deepEqual(violations, [], `type eksik düğmeler: ${violations.join(', ')}`);
+});