feat: validate SplitToLines arguments

ECoreNetto.Extensions.Tests/StringExtensionsTestFixture.cs

@@ -43,6 +43,14 @@ public void Verify_that_SplitToLines_returns_expected_results()
             Assert.That(lines, Is.EquivalentTo(new List<string> {"ab", "c", "def"}));
         }
 
+        [Test]
+        public void Verify_that_SplitToLines_validates_arguments()
+        {
+            Assert.Throws<ArgumentException>(() => StringExtensions.SplitToLines(null, 1));
+            Assert.Throws<ArgumentException>(() => "".SplitToLines(1));
+            Assert.Throws<ArgumentException>(() => "test".SplitToLines(0));
+        }
+
         [Test]
         public void Verify_that_CapitalizeFirstLetter_returns_expected_result()
         {

ECoreNetto.Extensions/StringExtensions.cs

@@ -42,8 +42,18 @@
         /// <returns>
         /// an <see cref="IEnumerable{String}"/>
         /// </returns>
         public static IEnumerable<string> SplitToLines(this string input, int maximumLineLength)
         {
+            if (string.IsNullOrWhiteSpace(input))
+            {
+                throw new ArgumentException("string can't be empty!");
+            }
+
+            if (maximumLineLength <= 0)
+            {
+                throw new ArgumentException("maximumLineLength must be greater than zero");
+            }
+
             input = input.Replace("\r\n", " ").Trim();
 
             var words = input.Split(' ');