From 216aa72d39b0ca49f1f17eeb1ca3e986fa908f6e Mon Sep 17 00:00:00 2001
From: fiatcode <fiatcode@posteo.com>
Date: Tue, 10 Feb 2026 09:33:44 +0700
Subject: [PATCH] RED: test roman numerals contraints

---
 test/roman_numerals_test.dart | 14 ++++++++++++++
 1 file changed, 14 insertions(+)

diff --git a/test/roman_numerals_test.dart b/test/roman_numerals_test.dart
index d9c8619..831aa9c 100644
--- a/test/roman_numerals_test.dart
+++ b/test/roman_numerals_test.dart
@@ -66,5 +66,19 @@ void main() {
         () => expect(integerToRoman(3999), 'MMMCMXCIX'),
       );
     });
+
+    group('Error Handling', () {
+      test('rejects zero', () {
+        expect(() => integerToRoman(0), throwsArgumentError);
+      });
+
+      test('rejects negative numbers', () {
+        expect(() => integerToRoman(-5), throwsArgumentError);
+      });
+
+      test('rejects numbers above 3999', () {
+        expect(() => integerToRoman(4000), throwsArgumentError);
+      });
+    });
   });
 }