DefaultIfNullOrWhiteSpace (#10)

Author: ChrisSimmons

NetChris.Core.UnitTests/DefaultIfNullOrWhiteSpaceTests.cs

@@ -0,0 +1,32 @@
+using FluentAssertions;
+using Xunit;
+
+namespace NetChris.Core.UnitTests;
+
+public class DefaultIfNullOrWhiteSpaceTests
+{
+    [Fact]
+    public void NullShouldReturnDefault()
+    {
+        string? nullString = null;
+        nullString.DefaultIfNullOrWhiteSpace("default").Should().Be("default");
+    }
+
+    [Fact]
+    public void EmptyStringShouldReturnDefault()
+    {
+        "".DefaultIfNullOrWhiteSpace("default").Should().Be("default");
+    }
+
+    [Fact]
+    public void WhiteSpaceShouldReturnDefault()
+    {
+        "  \t\n".DefaultIfNullOrWhiteSpace("default").Should().Be("default");
+    }
+
+    [Fact]
+    public void NonNullNonWhiteSpaceShouldReturnValue()
+    {
+        " Some string  \t".DefaultIfNullOrWhiteSpace("default").Should().Be(" Some string  \t");
+    }
+}

NetChris.Core/StringExtensions.cs

@@ -26,4 +26,10 @@ public static class StringExtensions
 
         return result;
     }
+    
+    /// <summary>
+    /// Returns a default value if the string is null or whitespace, otherwise the original string
+    /// </summary>
+    public static string DefaultIfNullOrWhiteSpace(this string? value, string defaultValue) =>
+        string.IsNullOrWhiteSpace(value) ? defaultValue : value!;
 }