GraphQL\Validator\DocumentValidator::validate PHP Method

    public static function validate(Schema $schema, DocumentNode $ast, array $rules = null)
    {
        $typeInfo = new TypeInfo($schema);
        $errors = static::visitUsingRules($schema, $typeInfo, $ast, $rules ?: static::allRules());
        return $errors;
    }

 function expectInvalid($schema, $rules, $queryString, $errors)
 {
     $result = DocumentValidator::validate($schema, Parser::parse($queryString), $rules);
     $this->assertEquals(false, $result['isValid'], 'GraphQL should not validate');
     $this->assertEquals($errors, $result['errors']);
     return $result;
 }