diff --git a/ExercisesForProgrammers/Bill.cs b/ExercisesForProgrammers/Bill.cs
index 7d44908..b7c1d4a 100644
--- a/ExercisesForProgrammers/Bill.cs
+++ b/ExercisesForProgrammers/Bill.cs
@@ -12,7 +12,7 @@ public double Subtotal {
                 if (this._tip == null) {
                     this._tip = new Tip();
                 }
-	            this.Tip.Calculate(value, this.Tip.PercentageOfSubtotal);
+                this._tip.Calculate(value, this._tip.PercentageOfSubtotal);
 				_subtotal = value;
 			}
         }
@@ -25,33 +25,19 @@ public Tip Tip
                 return _tip;
 			}
 			set
-			{ //TODO: Write a test for this.
-                this.Subtotal = value.Subtotal;
-                this.Total = _subtotal + value.Value;
+			{
                 _tip = value;
-			}
-        }
-
-        public double Total { get; private set; }
-
-
-        public Bill()
-        {
-            this.Tip = new Tip();
+				this.Subtotal = value.Subtotal;
+            }
         }
 
-		public Bill(double subtotal, Tip tip)
-        {
-            this._subtotal = subtotal;
-
-            if (subtotal.CompareTo(tip.Subtotal) == 0 || tip.Value.CompareTo(0D) == 0)
+        public double Total
+        { 
+            get
             {
-                this._tip = tip;
-            }
-            else
-            {
-                throw new ArgumentException("Tip given not calculated against given subtotal");
+                return _subtotal + this._tip.Value;
             }
         }
+
     }
 }
diff --git a/ExercisesForProgrammers/Program.cs b/ExercisesForProgrammers/Program.cs
index 2900c8f..c1607a9 100644
--- a/ExercisesForProgrammers/Program.cs
+++ b/ExercisesForProgrammers/Program.cs
@@ -16,9 +16,9 @@ public static void Main(string[] args)
             var newTip = new Tip(newBill.Subtotal, percentageOfSubtotal); //Assignment of subtotal is a bit odd here.
             newBill.Tip = newTip;
 
-            Console.WriteLine($"The tip is {newTip.Value}. ");
+            Console.WriteLine($"The tip is {newTip.Value.ToString("C")}. ");
 
-            Console.WriteLine($"The total is {newBill.Total}. ");
+            Console.WriteLine($"The total is {newBill.Total.ToString("C")}. ");
 
             Console.ReadLine(); // Wait for user to end program.
         }
diff --git a/ExercisesForProgrammers/Tip.cs b/ExercisesForProgrammers/Tip.cs
index 82a5668..e3c1c00 100644
--- a/ExercisesForProgrammers/Tip.cs
+++ b/ExercisesForProgrammers/Tip.cs
@@ -42,7 +42,12 @@ public Tip(double subtotal, int percentageOfSubtotal) {
         }
 
         public double Calculate(double subtotal, int percentageOfSubtotal) {
-            var result = subtotal * (percentageOfSubtotal / 100);
+            this._subtotal = subtotal;
+            this._percentageOfSubtotal = percentageOfSubtotal;
+
+            var result = ((double)percentageOfSubtotal / 100d);
+            result = subtotal * result;
+
             this.Value = result;
             return result;
         }
diff --git a/TipCalculator.Tests/EndToEndTest.cs b/TipCalculator.Tests/EndToEndTest.cs
deleted file mode 100644
index 774d867..0000000
--- a/TipCalculator.Tests/EndToEndTest.cs
+++ /dev/null
@@ -1,13 +0,0 @@
-using System;
-using NUnit.Framework;
-
-namespace TipCalculator.Tests
-{
-    [TestFixture]
-    public class EndToEndTest
-    {
-        public EndToEndTest()
-        {
-        }
-    }
-}
diff --git a/TipCalculator.Tests/FunctionalTests.cs b/TipCalculator.Tests/FunctionalTests.cs
new file mode 100644
index 0000000..02e6c26
--- /dev/null
+++ b/TipCalculator.Tests/FunctionalTests.cs
@@ -0,0 +1,81 @@
+using System;
+using NUnit.Framework;
+using ExercisesForProgrammers; //TipCalculator project
+
+namespace TipCalculator.Tests
+{
+    [TestFixture]
+    public class FunctionalTests
+    {
+        [Test]
+        public void BillAndTipSetupWithRealisticValues_ShouldCalculateTipAmountAndTotal()
+        {
+            //arrange
+
+            //input
+            double billAmount = 10.00; //dollars
+            int tipRate = 15; //percent (of subtotal)
+
+            double expectedTipAmount = 1.50; //dollars
+            double expectedTotalAmount = 11.50; //dollars
+
+            //act
+            var tip = new Tip();
+            double actualTipAmount = tip.Calculate(billAmount, tipRate);
+
+            var bill = new Bill() { Tip = tip };
+            var actualTotalAmount = bill.Total;
+
+            //assert
+            Assert.AreEqual(expectedTipAmount, actualTipAmount, "Actual tip amount does not equal expected tip amount.");
+            Assert.AreEqual(expectedTotalAmount, actualTotalAmount, "Actual total amount does not equal expected total amount.");
+        }
+
+        [Test]
+        public void GoodTest_OutputFormatting()
+        {
+            //arrange
+            string expectedTipFormat = "$1.50";
+            double tipAmount = 1.50d;
+
+            //act
+            var actualTipFormatted = tipAmount.ToString("C");
+
+            //assert
+            Assert.AreEqual(expectedTipFormat, actualTipFormatted);
+        }
+
+        [Test]
+        public void Test_ZeroTipPercentageInput()
+        {
+			throw new NotImplementedException();
+        }
+
+        /// <summary>
+        /// Defines the current requirement 
+        /// -- might be nice to have a minimum tip in the future.
+        /// </summary>
+        [Test]
+        public void Test_ZeroSubtotalInput()
+        {
+			throw new NotImplementedException();
+        }
+
+        [Test]
+        public void BadCase_NonNumericInput_ShouldOutputErrorMessage() {
+            throw new NotImplementedException();    
+        }
+
+        [Test]
+        public void BaseCase_NegativeTipPercentage_ShouldOutputErrorMessage() {
+            throw new NotImplementedException();
+        }
+
+		[Test]
+		public void BaseCase_NegativeSubtotal_ShouldOutputErrorMessage()
+		{
+			throw new NotImplementedException();
+		}
+
+    }
+}
diff --git a/TipCalculator.Tests/TipCalculator.Tests.csproj b/TipCalculator.Tests/TipCalculator.Tests.csproj
index 379d183..10519f6 100644
--- a/TipCalculator.Tests/TipCalculator.Tests.csproj
+++ b/TipCalculator.Tests/TipCalculator.Tests.csproj
@@ -33,10 +33,16 @@
   <ItemGroup>
     <Compile Include="BillTests.cs" />
     <Compile Include="TipTests.cs" />
-    <Compile Include="EndToEndTest.cs" />
+    <Compile Include="FunctionalTests.cs" />
   </ItemGroup>
   <ItemGroup>
     <None Include="packages.config" />
   </ItemGroup>
+  <ItemGroup>
+    <ProjectReference Include="..\ExercisesForProgrammers\TipCalculator.csproj">
+      <Project>{C1ACE25A-6829-4563-9636-E08DC4DAD01C}</Project>
+      <Name>TipCalculator</Name>
+    </ProjectReference>
+  </ItemGroup>
   <Import Project="$(MSBuildBinPath)\Microsoft.CSharp.targets" />
 </Project>
\ No newline at end of file