Extract url validator to its own file

lib/core/validators.dart

@@ -0,0 +1,29 @@
+import 'package:wger/l10n/generated/app_localizations.dart';
+
+String? validateUrl(String? value, AppLocalizations i18n, {bool required = true}) {
+  // Required?
+  if (required && (value == null || value.trim().isEmpty)) {
+    return i18n.enterValue;
+  }
+
+  if (!required && (value == null || value.trim().isEmpty)) {
+    return null;
+  }
+  value = value!.trim();
+
+  if (!value.startsWith('http://') && !value.startsWith('https://')) {
+    return i18n.invalidUrl;
+  }
+
+  // Try to parse as URI
+  try {
+    final uri = Uri.parse(value);
+    if (!uri.hasScheme || !uri.hasAuthority) {
+      return i18n.invalidUrl;
+    }
+  } catch (e) {
+    return i18n.invalidUrl;
+  }
+
+  return null;
+}

lib/helpers/exercises/forms.dart

@@ -1,36 +0,0 @@
-import 'package:flutter/material.dart';
-import 'package:wger/l10n/generated/app_localizations.dart';
-
-/// The amount of characters an exercise description needs to have
-const MIN_CHARS_DESCRIPTION = 40;
-
-/// The amount of characters an exercise name needs to have
-const MIN_CHARS_NAME = 5;
-const MAX_CHARS_NAME = 40;
-
-String? validateName(String? name, BuildContext context) {
-  if (name!.isEmpty) {
-    return AppLocalizations.of(context).enterValue;
-  }
-
-  if (name.length < MIN_CHARS_NAME || name.length > MAX_CHARS_NAME) {
-    return AppLocalizations.of(context).enterCharacters(
-      MIN_CHARS_NAME.toString(),
-      MAX_CHARS_NAME.toString(),
-    );
-  }
-
-  return null;
-}
-
-String? validateExerciseDescription(String? name, BuildContext context) {
-  if (name!.isEmpty) {
-    return AppLocalizations.of(context).enterValue;
-  }
-
-  if (name.length < MIN_CHARS_DESCRIPTION) {
-    return AppLocalizations.of(context).enterMinCharacters(MIN_CHARS_DESCRIPTION.toString());
-  }
-
-  return null;
-}

lib/widgets/auth/server_field.dart

@@ -1,36 +1,26 @@
 import 'package:flutter/material.dart';
+import 'package:wger/core/validators.dart';
 import 'package:wger/l10n/generated/app_localizations.dart';
 
 class ServerField extends StatelessWidget {
   final TextEditingController controller;
   final Function(String?) onSaved;
 
-  const ServerField({
-    required this.controller,
-    required this.onSaved,
-    super.key,
-  });
+  const ServerField({required this.controller, required this.onSaved, super.key});
 
   @override
   Widget build(BuildContext context) {
+    final i18n = AppLocalizations.of(context);
+
     return TextFormField(
       key: const Key('inputServer'),
       decoration: InputDecoration(
-        labelText: AppLocalizations.of(context).customServerUrl,
-        helperText: AppLocalizations.of(context).customServerHint,
+        labelText: i18n.customServerUrl,
+        helperText: i18n.customServerHint,
         helperMaxLines: 4,
       ),
       controller: controller,
-      validator: (value) {
-        if (Uri.tryParse(value!) == null) {
-          return AppLocalizations.of(context).invalidUrl;
-        }
-
-        if (value.isEmpty || !value.contains('http')) {
-          return AppLocalizations.of(context).invalidUrl;
-        }
-        return null;
-      },
+      validator: (value) => validateUrl(value, i18n, required: true),
       onSaved: onSaved,
     );
   }

test/core/validators_test.dart

@@ -0,0 +1,49 @@
+import 'package:flutter_test/flutter_test.dart';
+import 'package:mockito/annotations.dart';
+import 'package:mockito/mockito.dart';
+import 'package:wger/core/validators.dart';
+import 'package:wger/l10n/generated/app_localizations.dart';
+
+import 'validators_test.mocks.dart';
+
+@GenerateMocks([AppLocalizations])
+void main() {
+  MockAppLocalizations mockI18n = MockAppLocalizations();
+
+  setUp(() {
+    mockI18n = MockAppLocalizations();
+
+    when(mockI18n.enterValue).thenReturn('Please enter a value');
+    when(mockI18n.invalidUrl).thenReturn('Invalid URL');
+  });
+
+  test('Required field empty returns error', () {
+    final result = validateUrl('', mockI18n, required: true);
+    expect(result, isNotNull);
+  });
+
+  test('Optional field empty returns no error', () {
+    final result = validateUrl('', mockI18n, required: false);
+    expect(result, isNull);
+  });
+
+  test('Invalid URL without http/https returns error', () {
+    final result = validateUrl('www.example.com', mockI18n);
+    expect(result, isNotNull);
+  });
+
+  test('Invalid URL with wrong protocol returns error', () {
+    final result = validateUrl('gopher://', mockI18n);
+    expect(result, isNotNull);
+  });
+
+  test('Valid http URL returns no error', () {
+    final result = validateUrl('http://example.com', mockI18n);
+    expect(result, isNull);
+  });
+
+  test('Valid https URL returns no error', () {
+    final result = validateUrl('https://example.com', mockI18n);
+    expect(result, isNull);
+  });
+}