Improve required validator joanpablo#377

lib/src/validators/required_validator.dart

@@ -9,11 +9,18 @@ class RequiredValidator extends Validator<dynamic> {
   @override
   Map<String, dynamic>? validate(AbstractControl<dynamic> control) {
     final error = <String, dynamic>{ValidationMessage.required: true};
+    final dynamic value = control.value;
 
-    if (control.value == null) {
+    if (value == null) {
+      return error;
+    } else if (value is String) {
+      return value.trim().isEmpty ? error : null;
+    } else if (value is Iterable && value.isEmpty) {
+      return error;
+    } else if (value is Map && value.isEmpty) {
+      return error;
+    } else if (value is Set && value.isEmpty) {
       return error;
-    } else if (control.value is String) {
-      return (control.value as String).trim().isEmpty ? error : null;
     }
 
     return null;

test/src/validators/required_validator_test.dart

@@ -0,0 +1,106 @@
+import 'package:flutter_test/flutter_test.dart';
+import 'package:reactive_forms/reactive_forms.dart';
+
+void main() {
+  group('Required validator tests', () {
+    test('FormControl is invalid if value is null', () {
+      final control = FormControl<String>(
+        value: null,
+        validators: [Validators.required],
+      );
+
+      expect(control.valid, false);
+      expect(control.errors, {
+        ValidationMessage.required: true,
+      });
+    });
+
+    test('FormControl is invalid if value is empty string', () {
+      final control = FormControl<String>(
+        value: '',
+        validators: [Validators.required],
+      );
+
+      expect(control.valid, false);
+      expect(control.errors, {
+        ValidationMessage.required: true,
+      });
+    });
+
+    test('FormControl is valid if value is non empty string', () {
+      final control = FormControl<String>(
+        value: 'non empty string',
+        validators: [Validators.required],
+      );
+
+      expect(control.valid, true);
+      expect(control.errors, <String, dynamic>{});
+    });
+
+    test('FormControl is invalid if value is empty list', () {
+      final control = FormControl<List<String>>(
+        value: [],
+        validators: [Validators.required],
+      );
+
+      expect(control.valid, false);
+      expect(control.errors, {
+        ValidationMessage.required: true,
+      });
+    });
+
+    test('FormControl is valid if value is non empty list', () {
+      final control = FormControl<List<String>>(
+        value: ['non empty string'],
+        validators: [Validators.required],
+      );
+
+      expect(control.valid, true);
+      expect(control.errors, <String, dynamic>{});
+    });
+
+    test('FormControl is invalid if value is empty map', () {
+      final control = FormControl<Map<String, dynamic>>(
+        value: <String, dynamic>{},
+        validators: [Validators.required],
+      );
+
+      expect(control.valid, false);
+      expect(control.errors, {
+        ValidationMessage.required: true,
+      });
+    });
+
+    test('FormControl is valid if value is non empty map', () {
+      final control = FormControl<Map<String, String>>(
+        value: {'key': 'value'},
+        validators: [Validators.required],
+      );
+
+      expect(control.valid, true);
+      expect(control.errors, <String, dynamic>{});
+    });
+
+    test('FormControl is invalid if value is empty set', () {
+      final control = FormControl<Set<String>>(
+        value: <String>{},
+        validators: [Validators.required],
+      );
+
+      expect(control.valid, false);
+      expect(control.errors, {
+        ValidationMessage.required: true,
+      });
+    });
+
+    test('FormControl is valid if value is non empty set', () {
+      final control = FormControl<Set<String>>(
+        value: {'value'},
+        validators: [Validators.required],
+      );
+
+      expect(control.valid, true);
+      expect(control.errors, <String, dynamic>{});
+    });
+  });
+}