fix: show cron validation field errors

test/back/cron-validation.test.cjs

@@ -0,0 +1,45 @@
+const assert = require('node:assert/strict');
+const test = require('node:test');
+
+const configPath = require.resolve('../../back/config');
+require.cache[configPath] = {
+  id: configPath,
+  filename: configPath,
+  loaded: true,
+  exports: { __esModule: true, default: { logPath: '/ql/data/log' } },
+  children: [],
+  paths: [],
+};
+
+const { commonCronSchema } = require('../../back/validation/schedule');
+const { Joi } = require('celebrate');
+
+const schema = Joi.object(commonCronSchema);
+
+test('cron validation accepts leading-zero schedules and legacy null labels', () => {
+  const result = schema.validate({
+    name: 'legacy cron',
+    command: 'task legacy.js',
+    schedule: '01 7 * * *',
+    labels: null,
+  });
+
+  assert.equal(result.error, undefined);
+});
+
+test('cron validation identifies invalid fields', () => {
+  const result = schema.validate(
+    {
+      name: 'invalid cron',
+      command: 'task invalid.js',
+      schedule: '01 7 * * *',
+      allow_multiple_instances: '',
+    },
+    { abortEarly: false },
+  );
+
+  assert.deepEqual(
+    [...new Set(result.error.details.map((detail) => detail.path.join('.')))],
+    ['allow_multiple_instances'],
+  );
+});