Do not allow numbers less than -99999.99

Author: Yulian Ashikov

src/OneBitSoftware.Slovom/NumbersToWords.cs

@@ -136,6 +136,7 @@ private static string AppendNegativePrefix(string numberAsWords, bool isNegative
 
     public static string Convert(decimal number, CurrencyDescriptor currencyDescriptor)
     {
+        if (number < -99999.99m) throw new ArgumentOutOfRangeException(nameof(number), "Входното число не може да бъде по-малко от -99999.99");
         ArgumentNullException.ThrowIfNull(currencyDescriptor);
 
         if (number is 0 or 0.0m)  return currencyDescriptor.Vocabulary.NumbersZeroToNineteen[0] + currencyDescriptor.MajorCurrencyUnitPlural; // нула лева, нула евро

src/Tests/ConvertTests.cs

@@ -185,4 +185,12 @@ public void NumberToWordsEuro_ShouldReturnCorrectWordsForNegativeValues(decimal
         // Assert
         Assert.Equal(expected, result);
     }
+
+    [Theory]
+    [InlineData(-100000)]
+    public void Convert_WithNumberLessThanNegativeLimit_ShouldThrowArgumentOutOfRangeException(decimal number)
+    {
+        Assert.Throws<ArgumentOutOfRangeException>(() => NumbersToWords.Convert(number, CurrencyDescriptor.Bgn));
+        Assert.Throws<ArgumentOutOfRangeException>(() => NumbersToWords.Convert(number, CurrencyDescriptor.Euro));
+    }
 }