Issue #2: Resolve "Criar ValidationHandler"

Closes #2 (closed)

src/core/input.spec.ts

+/*
+ * form-creator-api. RESTful API to manage and answer forms.
+ * Copyright (C) 2019 Centro de Computacao Cientifica e Software Livre
+ * Departamento de Informatica - Universidade Federal do Parana - C3SL/UFPR
+ *
+ * This file is part of form-creator-api.
+ *
+ * This program is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU Affero General Public License as published by
+ * the Free Software Foundation, either version 3 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU Affero General Public License for more details.
+ *
+ * You should have received a copy of the GNU Affero General Public License
+ * along with this program.  If not, see <https://www.gnu.org/licenses/>.
+ */