Add test cases for the min value formatter

Author: theEvilReaper

test/util.formatter/min_value_formatter_integration_test.dart

@@ -0,0 +1,33 @@
+import 'package:flutter/material.dart';
+import 'package:flutter_test/flutter_test.dart';
+import 'package:stelaris/util/formatter/min_value_fomatter.dart';
+
+void main() {
+  testWidgets('TextField with MinValueFormatter behaves correctly',
+          (tester) async {
+        final controller = TextEditingController();
+
+        await tester.pumpWidget(
+          MaterialApp(
+            home: Scaffold(
+              body: TextField(
+                controller: controller,
+                inputFormatters: [MinValueFormatter(1)],
+              ),
+            ),
+          ),
+        );
+
+        // Enter "05"
+        await tester.enterText(find.byType(TextField), '05');
+        expect(controller.text, '5');
+
+        // Enter "0"
+        await tester.enterText(find.byType(TextField), '0');
+        expect(controller.text, '1'); // snapped to min
+
+        // Enter "21"
+        await tester.enterText(find.byType(TextField), '21');
+        expect(controller.text, '21');
+      });
+}

test/util.formatter/min_value_formatter_unit_test.dart

@@ -0,0 +1,53 @@
+import 'package:flutter/services.dart';
+import 'package:flutter_test/flutter_test.dart';
+import 'package:stelaris/util/formatter/min_value_fomatter.dart';
+
+void main() {
+  group('MinValueFormatter', () {
+    const min = 1;
+    final formatter = MinValueFormatter(min);
+
+    TextEditingValue format(String oldText, String newText, {int? cursor}) {
+      return formatter.formatEditUpdate(
+        TextEditingValue(
+          text: oldText,
+          selection: TextSelection.collapsed(offset: oldText.length),
+        ),
+        TextEditingValue(
+          text: newText,
+          selection: TextSelection.collapsed(offset: cursor ?? newText.length),
+        ),
+      );
+    }
+
+    test('empty input resets to min', () {
+      final result = format('2', '');
+      expect(result.text, '1');
+      expect(result.selection.baseOffset, '1'.length);
+    });
+
+    test('leading zero removed', () {
+      final result = format('', '01');
+      expect(result.text, '1');
+      expect(result.selection.baseOffset, 1);
+    });
+
+    test('below min resets to min', () {
+      final result = format('', '0');
+      expect(result.text, '1');
+      expect(result.selection.baseOffset, 1);
+    });
+
+    test('valid number stays as is', () {
+      final result = format('', '21');
+      expect(result.text, '21');
+      expect(result.selection.baseOffset, 2);
+    });
+
+    test('multiple leading zeros collapse', () {
+      final result = format('', '0007');
+      expect(result.text, '7');
+      expect(result.selection.baseOffset, 1);
+    });
+  });
+}