diff --git a/csharp/Platform.Setters.Tests/SetterTests.cs b/csharp/Platform.Setters.Tests/SetterTests.cs
index af0dc4c..cf36feb 100644
--- a/csharp/Platform.Setters.Tests/SetterTests.cs
+++ b/csharp/Platform.Setters.Tests/SetterTests.cs
@@ -1,3 +1,4 @@
+using System.Collections.Generic;
 using Xunit;
 
 namespace Platform.Setters.Tests
@@ -45,5 +46,261 @@ public void MethodsWithIntegerReturnTypeTest()
             Assert.Equal(0, setter.SetFirstAndReturnFalse(new int[] { 4 }));
             Assert.Equal(4, setter.Result);
         }
+
+        [Fact]
+        public void SetterBaseSetMethodTest()
+        {
+            Setter<string> setter = new Setter<string>();
+            setter.Set("test");
+            Assert.Equal("test", setter.Result);
+        }
+
+        [Fact]
+        public void SetterWithTDecisionParameterlessConstructorTest()
+        {
+            Setter<int, int> setter = new Setter<int, int>();
+            Assert.Equal(default, setter.Result);
+            Assert.Equal(default, setter.TrueValue);
+            Assert.Equal(default, setter.FalseValue);
+        }
+
+        [Fact]
+        public void SetterWithTDecisionDefaultValueConstructorTest()
+        {
+            Setter<string, bool> setter = new Setter<string, bool>("default");
+            Assert.Equal("default", setter.Result);
+            Assert.Equal(default, setter.TrueValue);
+            Assert.Equal(default, setter.FalseValue);
+        }
+
+        [Fact]
+        public void SetterWithTDecisionTrueAndFalseValuesConstructorTest()
+        {
+            Setter<int, string> setter = new Setter<int, string>("success", "failure");
+            Assert.Equal(default, setter.Result);
+            Assert.Equal("success", setter.TrueValue);
+            Assert.Equal("failure", setter.FalseValue);
+        }
+
+        [Fact]
+        public void SetterWithTDecisionFullConstructorTest()
+        {
+            Setter<int, string> setter = new Setter<int, string>("success", "failure", 42);
+            Assert.Equal(42, setter.Result);
+            Assert.Equal("success", setter.TrueValue);
+            Assert.Equal("failure", setter.FalseValue);
+        }
+
+        [Fact]
+        public void SetFirstAndReturnTrueWithNullListTest()
+        {
+            Setter<int> setter = new Setter<int>(100);
+            bool result = setter.SetFirstAndReturnTrue(null);
+            Assert.True(result);
+            Assert.Equal(100, setter.Result); // Should remain unchanged
+        }
+
+        [Fact]
+        public void SetFirstAndReturnFalseWithNullListTest()
+        {
+            Setter<int> setter = new Setter<int>(100);
+            bool result = setter.SetFirstAndReturnFalse(null);
+            Assert.False(result);
+            Assert.Equal(100, setter.Result); // Should remain unchanged
+        }
+
+        [Fact]
+        public void SetFirstAndReturnTrueWithCustomTDecisionTest()
+        {
+            Setter<string, int> setter = new Setter<string, int>(1, 0);
+            int result = setter.SetFirstAndReturnTrue(new string[] { "test" });
+            Assert.Equal(1, result);
+            Assert.Equal("test", setter.Result);
+        }
+
+        [Fact]
+        public void SetFirstAndReturnFalseWithCustomTDecisionTest()
+        {
+            Setter<string, int> setter = new Setter<string, int>(1, 0);
+            int result = setter.SetFirstAndReturnFalse(new string[] { "test" });
+            Assert.Equal(0, result);
+            Assert.Equal("test", setter.Result);
+        }
+    }
+
+    public class SetterExtensionsTests
+    {
+        [Fact]
+        public void SetFirstFromNonNullListAndReturnTrueTest()
+        {
+            var setter = new Setter<int, string>("success", "failure");
+            var list = new List<int> { 1, 2, 3 };
+            
+            string result = setter.SetFirstFromNonNullListAndReturnTrue(list);
+            
+            Assert.Equal("success", result);
+            Assert.Equal(1, setter.Result);
+        }
+
+        [Fact]
+        public void SetFirstFromNonNullListAndReturnTrueWithNullListTest()
+        {
+            var setter = new Setter<int, string>("success", "failure", 42);
+            
+            string result = setter.SetFirstFromNonNullListAndReturnTrue(null);
+            
+            Assert.Equal("success", result);
+            Assert.Equal(42, setter.Result); // Should remain unchanged
+        }
+
+        [Fact]
+        public void SetFirstFromNonNullFirstListAndReturnTrueTest()
+        {
+            var setter = new Setter<string, bool>(true, false);
+            var list1 = new List<string> { "first", "second" };
+            var list2 = new List<string> { "third", "fourth" };
+            
+            bool result = setter.SetFirstFromNonNullFirstListAndReturnTrue(list1, list2);
+            
+            Assert.True(result);
+            Assert.Equal("first", setter.Result);
+        }
+
+        [Fact]
+        public void SetFirstFromNonNullFirstListAndReturnTrueWithNullFirstListTest()
+        {
+            var setter = new Setter<string, bool>(true, false, "default");
+            var list2 = new List<string> { "third", "fourth" };
+            
+            bool result = setter.SetFirstFromNonNullFirstListAndReturnTrue(null, list2);
+            
+            Assert.True(result);
+            Assert.Equal("default", setter.Result); // Should remain unchanged
+        }
+
+        [Fact]
+        public void SetSecondFromNonNullFirstListAndReturnTrueTest()
+        {
+            var setter = new Setter<int, char>('T', 'F');
+            var list1 = new List<int> { 10, 20, 30 };
+            var list2 = new List<int> { 40, 50 };
+            
+            char result = setter.SetSecondFromNonNullFirstListAndReturnTrue(list1, list2);
+            
+            Assert.Equal('T', result);
+            Assert.Equal(20, setter.Result);
+        }
+
+        [Fact]
+        public void SetSecondFromNonNullFirstListAndReturnTrueWithNullFirstListTest()
+        {
+            var setter = new Setter<int, char>('T', 'F', 99);
+            var list2 = new List<int> { 40, 50 };
+            
+            char result = setter.SetSecondFromNonNullFirstListAndReturnTrue(null, list2);
+            
+            Assert.Equal('T', result);
+            Assert.Equal(99, setter.Result); // Should remain unchanged
+        }
+
+        [Fact]
+        public void SetThirdFromNonNullFirstListAndReturnTrueTest()
+        {
+            var setter = new Setter<double, byte>(1, 0);
+            var list1 = new List<double> { 1.1, 2.2, 3.3, 4.4 };
+            var list2 = new List<double> { 5.5, 6.6 };
+            
+            byte result = setter.SetThirdFromNonNullFirstListAndReturnTrue(list1, list2);
+            
+            Assert.Equal(1, result);
+            Assert.Equal(3.3, setter.Result);
+        }
+
+        [Fact]
+        public void SetThirdFromNonNullFirstListAndReturnTrueWithNullFirstListTest()
+        {
+            var setter = new Setter<double, byte>(1, 0, 9.9);
+            var list2 = new List<double> { 5.5, 6.6 };
+            
+            byte result = setter.SetThirdFromNonNullFirstListAndReturnTrue(null, list2);
+            
+            Assert.Equal(1, result);
+            Assert.Equal(9.9, setter.Result); // Should remain unchanged
+        }
+
+        [Fact]
+        public void SetFirstFromNonNullSecondListAndReturnTrueTest()
+        {
+            var setter = new Setter<string, int>(100, 0);
+            var list1 = new List<string> { "first", "second" };
+            var list2 = new List<string> { "third", "fourth" };
+            
+            int result = setter.SetFirstFromNonNullSecondListAndReturnTrue(list1, list2);
+            
+            Assert.Equal(100, result);
+            Assert.Equal("third", setter.Result);
+        }
+
+        [Fact]
+        public void SetFirstFromNonNullSecondListAndReturnTrueWithNullSecondListTest()
+        {
+            var setter = new Setter<string, int>(100, 0, "default");
+            var list1 = new List<string> { "first", "second" };
+            
+            int result = setter.SetFirstFromNonNullSecondListAndReturnTrue(list1, null);
+            
+            Assert.Equal(100, result);
+            Assert.Equal("default", setter.Result); // Should remain unchanged
+        }
+
+        [Fact]
+        public void SetSecondFromNonNullSecondListAndReturnTrueTest()
+        {
+            var setter = new Setter<float, long>(1L, -1L);
+            var list1 = new List<float> { 1.0f, 2.0f };
+            var list2 = new List<float> { 3.0f, 4.0f, 5.0f };
+            
+            long result = setter.SetSecondFromNonNullSecondListAndReturnTrue(list1, list2);
+            
+            Assert.Equal(1L, result);
+            Assert.Equal(4.0f, setter.Result);
+        }
+
+        [Fact]
+        public void SetSecondFromNonNullSecondListAndReturnTrueWithNullSecondListTest()
+        {
+            var setter = new Setter<float, long>(1L, -1L, 9.9f);
+            var list1 = new List<float> { 1.0f, 2.0f };
+            
+            long result = setter.SetSecondFromNonNullSecondListAndReturnTrue(list1, null);
+            
+            Assert.Equal(1L, result);
+            Assert.Equal(9.9f, setter.Result); // Should remain unchanged
+        }
+
+        [Fact]
+        public void SetThirdFromNonNullSecondListAndReturnTrueTest()
+        {
+            var setter = new Setter<char, bool>(true, false);
+            var list1 = new List<char> { 'a', 'b' };
+            var list2 = new List<char> { 'x', 'y', 'z', 'w' };
+            
+            bool result = setter.SetThirdFromNonNullSecondListAndReturnTrue(list1, list2);
+            
+            Assert.True(result);
+            Assert.Equal('z', setter.Result);
+        }
+
+        [Fact]
+        public void SetThirdFromNonNullSecondListAndReturnTrueWithNullSecondListTest()
+        {
+            var setter = new Setter<char, bool>(true, false, 'X');
+            var list1 = new List<char> { 'a', 'b' };
+            
+            bool result = setter.SetThirdFromNonNullSecondListAndReturnTrue(list1, null);
+            
+            Assert.True(result);
+            Assert.Equal('X', setter.Result); // Should remain unchanged
+        }
     }
 }