more tests

bzTorrent.Tests/Extensions/ExtensionsTests.cs

@@ -0,0 +1,50 @@
+using FluentAssertions;
+using System;
+using System.Diagnostics;
+using bzTorrent.Helpers;
+using Xunit;
+using bzTorrent.Data;
+using bzTorrent.Extensions;
+using System.Collections.Generic;
+
+namespace bzTorrent.Tests.Extensions
+{
+    public class ExtensionsTests
+    {
+        [Fact]
+        public void IsNullOrEmptyReturnsTrueForEmptyArray()
+        {
+            Array.Empty<object>().IsNullOrEmpty().Should().BeTrue();
+        }
+
+        [Fact]
+        public void IsNullOrEmptyReturnsFalseForArrayWithObjects()
+        {
+            var array = new List<object>() { new object(), new object(), new object() };
+            array.IsNullOrEmpty().Should().BeFalse();
+        }
+
+        [Fact]
+        public void IsNullOrEmptyReturnsTrueForNullCastedToArray()
+        {
+            var nullArray = (object[])null;
+            nullArray.IsNullOrEmpty().Should().BeTrue();
+        }
+
+        [Fact]
+        public void ThrowIfNullThrowsExceptionForNull()
+        {
+            object x = null;
+            var ex = Record.Exception(() => x.ThrowIfNull(nameof(x)));
+            Assert.NotNull(ex);
+        }
+
+        [Fact]
+        public void ThrowIfNullDoesNotThrowExceptionForValidObject()
+        {
+            object x = new();
+            var ex = Record.Exception(() => x.ThrowIfNull(nameof(x)));
+            Assert.Null(ex);
+        }
+    }
+}

bzTorrent/Extensions/ArgumentExtensions.cs

@@ -47,7 +47,7 @@ public static void ThrowIfNullOrEmpty<T>(this IEnumerable<T> source, string para
 		{
 			if (source.IsNullOrEmpty())
 			{
-				throw new ArgumentNullException("Enumerable cannot be null or empty", paramName);
+				throw new ArgumentNullException(paramName, "Cannot be null or empty");
 			}
 		}
 	}