diff --git a/README.md b/README.md
index c3791e9..e195837 100644
--- a/README.md
+++ b/README.md
@@ -23,9 +23,9 @@ Manually checking properties for emptinness leaves an opportunity to miss someth
 * [Nunit](https://www.nuget.org/packages/kasthack.NotEmpty.Nunit/)
 * [Xunit](https://www.nuget.org/packages/kasthack.NotEmpty.Xunit/)
 * [MsTest](https://www.nuget.org/packages/kasthack.NotEmpty.MsTest/)
-* [Plain .NET](https://www.nuget.org/packages/kasthack.NotEmpty.Raw/)
+* [<no frameworks>](https://www.nuget.org/packages/kasthack.NotEmpty.Raw/)
 
-2. Check your objects / their properties for emptinness.
+2. Check your objects / their properties for emptinness. Look at the <a href="src/kasthack.NotEmpty.Tests/NotEmptyTestBase.cs">tests</a> for more details.
 
 ````csharp
 using kasthack.NotEmpty.Xunit;  // replace the namespace to match your test framework
diff --git a/src/kasthack.NotEmpty.Core/NotEmptyExtensionsBase.cs b/src/kasthack.NotEmpty.Core/NotEmptyExtensionsBase.cs
index 73539d6..cb90078 100644
--- a/src/kasthack.NotEmpty.Core/NotEmptyExtensionsBase.cs
+++ b/src/kasthack.NotEmpty.Core/NotEmptyExtensionsBase.cs
@@ -9,7 +9,7 @@ public abstract class NotEmptyExtensionsBase
     {
         public void NotEmpty<T>(T? value)
         {
-            // workaround for boxed structs
+            // workaround for boxed structs passed as objects
             if (value is not null && typeof(T) == typeof(object) && value.GetType() != typeof(object))
             {
                 this.NotEmptyBoxed(value, null!);
@@ -23,6 +23,7 @@ public void NotEmpty<T>(T? value)
         private void NotEmptyInternal<T>(T? value, string? path = null)
         {
             string message = GetEmptyMessage(path);
+            this.Assert(value is not null, message); //fast lane
             this.Assert(!EqualityComparer<T>.Default.Equals(default!, value!), message);
             switch (value)
             {
@@ -48,10 +49,7 @@ private void NotEmptyInternal<T>(T? value, string? path = null)
             }
         }
 
-        private static string GetEmptyMessage(string? path)
-        {
-            return $"value{path} is empty";
-        }
+        private static string GetEmptyMessage(string? path) => $"value{path} is empty";
 
         private void NotEmptyBoxed(object? value, string? path)
         {
@@ -65,9 +63,9 @@ private static class CachedEmptyDelegate
                 .GetMethod(nameof(NotEmptyExtensionsBase.NotEmptyInternal), BindingFlags.NonPublic | BindingFlags.Instance)!
                 .GetGenericMethodDefinition();
 
-            private static readonly Dictionary<Type, Action<object?, string>> Delegates = new();
+            private static readonly Dictionary<Type, Action<object?, string?>> Delegates = new();
 
-            public static Action<object?, string> GetDelegate(NotEmptyExtensionsBase @this, Type type)
+            public static Action<object?, string?> GetDelegate(NotEmptyExtensionsBase @this, Type type)
             {
                 if (!Delegates.TryGetValue(type, out var result))
                 {
@@ -77,7 +75,7 @@ private static class CachedEmptyDelegate
                         {
                             var valueParam = Expression.Parameter(typeof(object));
                             var pathParam = Expression.Parameter(typeof(string));
-                            result = (Action<object?, string>)Expression
+                            result = (Action<object?, string?>)Expression
                                 .Lambda(
                                     Expression.Call(
                                         Expression.Constant(@this),
diff --git a/src/kasthack.NotEmpty.Tests/NotEmptyTestBase.cs b/src/kasthack.NotEmpty.Tests/NotEmptyTestBase.cs
index 70a127b..52895cc 100644
--- a/src/kasthack.NotEmpty.Tests/NotEmptyTestBase.cs
+++ b/src/kasthack.NotEmpty.Tests/NotEmptyTestBase.cs
@@ -30,7 +30,10 @@ public abstract class NotEmptyTestBase
         public void PrimitiveWorks() => this.action(1);
 
         [Fact]
-        public void ZeroThrows() => Assert.ThrowsAny<Exception>(() => this.action(0));
+        public void EmptyStringThrows() => Assert.ThrowsAny<Exception>(() => this.action(string.Empty));
+
+        [Fact]
+        public void DefaultThrows() => Assert.ThrowsAny<Exception>(() => this.action(0));
 
         [Fact]
         public void EmptyArrayThrows() => Assert.ThrowsAny<Exception>(() => this.action(new object[] { }));
@@ -39,15 +42,15 @@ public abstract class NotEmptyTestBase
         public void EmptyListThrows() => Assert.ThrowsAny<Exception>(() => this.action(new List<object>()));
 
         [Fact]
-        public void ListWorks() => this.action(new List<object> { new object() });
+        public void ArrayWithDefaultThrows() => Assert.ThrowsAny<Exception>(() => this.action(new object[] { 1, 0 }));
 
         [Fact]
-        public void ArrayWorks() => this.action(new object[] { new object() });
+        public void ArrayWithNullThrows() => Assert.ThrowsAny<Exception>(() => this.action(new object?[] { null, new object() }));
 
         [Fact]
-        public void ArrayWithDefaultThrows() => Assert.ThrowsAny<Exception>(() => this.action(new object[] { 1, 0 }));
+        public void ListWorks() => this.action(new List<object> { new object() });
 
         [Fact]
-        public void ArrayWithNullThrows() => Assert.ThrowsAny<Exception>(() => this.action(new object?[] { null, new object() }));
+        public void ArrayWorks() => this.action(new object[] { new object() });
     }
 }
\ No newline at end of file
diff --git a/src/kasthack.NotEmpty.Tests/kasthack.NotEmpty.Tests.csproj b/src/kasthack.NotEmpty.Tests/kasthack.NotEmpty.Tests.csproj
index 8b5212d..21e0541 100644
--- a/src/kasthack.NotEmpty.Tests/kasthack.NotEmpty.Tests.csproj
+++ b/src/kasthack.NotEmpty.Tests/kasthack.NotEmpty.Tests.csproj
@@ -1,9 +1,8 @@
 <Project Sdk="Microsoft.NET.Sdk">
 
   <PropertyGroup>
-    <TargetFramework>net6.0</TargetFramework>
+    <TargetFramework>net461</TargetFramework>
     <Nullable>enable</Nullable>
-
     <IsPackable>false</IsPackable>
   </PropertyGroup>