implement isInt validator tests

Author: ArturAssisComp

lib/new_api_prototype/core_validators/type_validators.dart

@@ -32,13 +32,19 @@ Validator<T> isString<T extends Object>([
   return (false, null);
 }
 
-Validator<T> isInt<T extends Object>(Validator<int>? v, {String? isIntMsg}) {
+/// This function returns a validator that checks if the user input is either an
+/// `int` or a `String` that is parsable to an `int`.
+/// If it checks positive, then it returns null when `next` is not provided. Otherwise,
+/// if `next` is provided, it passes the transformed value as `int` to the `next`
+/// validator.
+Validator<T> isInt<T extends Object>([Validator<int>? next, String? isIntMsg]) {
   String? finalValidator(T value) {
-    final (isValid, typeTransformedValue) = _isIntValidateAndConvert(value);
+    final (bool isValid, int? typeTransformedValue) =
+        _isIntValidateAndConvert(value);
     if (!isValid) {
       return isIntMsg ?? FormBuilderLocalizations.current.integerErrorText;
     }
-    return v?.call(typeTransformedValue!);
+    return next?.call(typeTransformedValue!);
   }
 
   return finalValidator;

test/new_api_testing/core_validators/type_validators_test.dart

@@ -5,6 +5,7 @@ void main() {
   const String errorMsg = 'error msg';
   String? hasLengthGreaterThan3(String input) =>
       input.length > 3 ? null : errorMsg;
+  String? isEven(int input) => input % 2 == 0 ? null : errorMsg;
 
   group('Validator: isString', () {
     test('Should only check if the input is a String', () {
@@ -33,4 +34,41 @@ void main() {
       expect(v('12'), isNull);
     });
   });
+
+  group('Validator: isInt', () {
+    test('Should only check if the input is an int/parsable to int', () {
+      final Validator<Object> v = isInt();
+
+      expect(v('not an int'),
+          equals(FormBuilderLocalizations.current.integerErrorText));
+      expect(
+          v('1-3'), equals(FormBuilderLocalizations.current.integerErrorText));
+      expect(v('123.0'),
+          equals(FormBuilderLocalizations.current.integerErrorText));
+      expect(
+          v(123.0), equals(FormBuilderLocalizations.current.integerErrorText));
+      expect(v('123'), isNull);
+      expect(v('1'), isNull);
+      expect(v(24), isNull);
+      expect(v(-24), isNull);
+      expect(v('-0'), isNull);
+    });
+    test('Should check if the input is an even integer', () {
+      final Validator<Object> v = isInt(isEven);
+
+      expect(v('not an int'),
+          equals(FormBuilderLocalizations.current.integerErrorText));
+      expect(v('1234'), isNull);
+      expect(v(-4), isNull);
+      expect(v('1233'), equals(errorMsg));
+    });
+    test('Should check if the input is an int using custom error', () {
+      const String customError = 'custom error';
+      final Validator<Object> v = isInt(null, customError);
+
+      expect(v('not int'), equals(customError));
+      expect(v('23'), isNull);
+      expect(v(23), isNull);
+    });
+  });
 }