diff --git a/Refactoring/Store.cs b/Refactoring/Store.cs
index d9a7c78..48fcad6 100644
--- a/Refactoring/Store.cs
+++ b/Refactoring/Store.cs
@@ -32,7 +32,7 @@ public void Purchase(string productId, int quantity)
                 throw new OutOfStockException();
             }
 
-            product.Quantity = product.Quantity - quantity+1;
+            product.Quantity = product.Quantity - quantity;
             user.Balance = user.Balance - product.Price * quantity;
 
             dataManager.SaveUser(user);
diff --git a/UnitTestProject/AuthenticatorTests.cs b/UnitTestProject/AuthenticatorTests.cs
new file mode 100644
index 0000000..b8a5362
--- /dev/null
+++ b/UnitTestProject/AuthenticatorTests.cs
@@ -0,0 +1,104 @@
+using Newtonsoft.Json;
+using NUnit.Framework;
+using Refactoring;
+using System;
+using System.Collections.Generic;
+using System.IO;
+using System.Linq;
+using System.Text;
+using System.Threading.Tasks;
+
+namespace UnitTestProject
+{
+    /// <summary>
+    /// Summary description for AuthenticatorTests
+    /// </summary>
+    [TestFixture]
+    public class AuthenticatorTests
+    {
+
+        private User createTestUser(string name, string password, double balance)
+        {
+            User testUser = new User();
+            testUser.Name = name;
+            testUser.Password = password;
+            testUser.Balance = balance;
+
+            return testUser;
+        }
+
+        private Authenticator SetUpAuthenticatorAndTestUserList()
+        {
+            var users = new List<User>();
+            users.Add(createTestUser("user1", "abcd", 99.99));
+            users.Add(createTestUser("user2", "1234", 9.99));
+            return new Authenticator(users);
+        }
+
+        [Test]
+        public void Test_AuthenticateReturnsUserOnSuccess()
+        {
+            //Arrange
+            var authenticator = SetUpAuthenticatorAndTestUserList();
+            //Act
+            var returnedValue = authenticator.Authenticate("user1", "abcd");
+            //Assert
+            Assert.IsInstanceOf<User>(returnedValue);
+        }
+
+        [Test]
+        public void Test_AuthenticateReturnsNULLOnBadPassword()
+        {
+            //Arrange
+            var authenticator = SetUpAuthenticatorAndTestUserList();
+            //Act
+            var returnedValue = authenticator.Authenticate("user1", "ab34");
+            //Assert
+            Assert.IsNull(returnedValue);
+        }
+
+        [Test]
+        public void Test_AuthenticateReturnsNULLOnBadUsername()
+        {
+            //Arrange
+            var authenticator = SetUpAuthenticatorAndTestUserList();
+            //Act
+            var returnedValue = authenticator.Authenticate("user3", "abcd");
+            //Assert
+            Assert.IsNull(returnedValue);
+        }
+
+
+
+
+        // THE BELOW CODE IS REQUIRED TO PREVENT THE TESTS FROM MODIFYING THE USERS/PRODUCTS ON FILE
+        //  This is not a good unit testing pattern - the unit test dependency on the file system should
+        //  actually be broken ... training on how to do this will be coming.
+        private List<User> originalUsers;
+        private List<Product> originalProducts;
+
+        [SetUp]
+        public void Test_Initialize()
+        {
+            // Load users from data file
+            originalUsers = JsonConvert.DeserializeObject<List<User>>(File.ReadAllText(@"Data/Users.json"));
+
+            // Load products from data file
+            originalProducts = JsonConvert.DeserializeObject<List<Product>>(File.ReadAllText(@"Data/Products.json"));
+        }
+
+
+
+        [TearDown]
+        public void Test_Cleanup()
+        {
+            // Restore users
+            string json = JsonConvert.SerializeObject(originalUsers, Formatting.Indented);
+            File.WriteAllText(@"Data/Users.json", json);
+
+            // Restore products
+            string json2 = JsonConvert.SerializeObject(originalProducts, Formatting.Indented);
+            File.WriteAllText(@"Data/Products.json", json2);
+        }
+    }
+}
diff --git a/UnitTestProject/IntegrationTests.cs b/UnitTestProject/IntegrationTests.cs
index f526b8a..ddb4fb9 100644
--- a/UnitTestProject/IntegrationTests.cs
+++ b/UnitTestProject/IntegrationTests.cs
@@ -10,7 +10,7 @@
 namespace UnitTestProject
 {
     [TestFixture]
-    //[Ignore("Disable integration tests")]
+    [Ignore("Disable integration tests")]
     public class IntegrationTests
     {
         private List<User> users;
diff --git a/UnitTestProject/StoreTests.cs b/UnitTestProject/StoreTests.cs
index 9f0b866..9a3e1ce 100644
--- a/UnitTestProject/StoreTests.cs
+++ b/UnitTestProject/StoreTests.cs
@@ -34,20 +34,29 @@ private Product createTestProduct(string id, string name, double price, int quan
             return testProduct;
         }
 
-        [Test]
-        public void Test_PurchaseThrowsNoErrorForValidFunds()
+        private Store purchaseMethodSetupSingleUserSingleProduct(double balance, string id, double price, int quantity)
         {
-            //Arrange
-            const string TEST_PRODUCT_ID = "1";
-
             var users = new List<User>();
-            users.Add(createTestUser("Test User", "", 99.99));
+            users.Add(createTestUser("Test User", "", balance));
 
             var products = new List<Product>();
-            products.Add(createTestProduct(TEST_PRODUCT_ID, "Product", 9.99, 10));
+            products.Add(createTestProduct(id, "Product", price, quantity));
 
             var dataManager = new DataManager(users, products);
-            var store = new Store(users[0], dataManager);
+            return new Store(users[0], dataManager);
+            
+        }
+
+
+
+        [Test]
+        public void Test_PurchaseThrowsNoErrorForValidFunds()
+        {
+            //Arrange
+            
+            const string TEST_PRODUCT_ID = "1";
+            var store = purchaseMethodSetupSingleUserSingleProduct(99.99,TEST_PRODUCT_ID, 9.99, 10);
+
 
             //Act
             store.Purchase(TEST_PRODUCT_ID, 10);
@@ -60,34 +69,66 @@ public void Test_PurchaseThrowsNoErrorForValidFunds()
         public void Test_PurchaseRemovesProductFromStore()
         {
             //Arrange
+            const string TEST_PRODUCT_ID = "1";
+            var store = purchaseMethodSetupSingleUserSingleProduct(99.99, TEST_PRODUCT_ID, 9.99, 10);
 
             //Act
+            store.Purchase(TEST_PRODUCT_ID, 9);
 
             //Assert 
             //(choose the appropriate statement(s))
-            //Assert.AreEqual(1, products[0].Quantity);
-            //Assert.AreSame(1, products[0].Quantity);
-            //Assert.IsTrue(products[0].Quantity == 1);
+            Assert.AreEqual(1, store.GetProductById(TEST_PRODUCT_ID).Quantity);
+            //Assert.AreSame(1, store.GetProductById(TEST_PRODUCT_ID).Quantity);
+            Assert.IsTrue(store.GetProductById(TEST_PRODUCT_ID).Quantity == 1);
         }
 
         [Test]
         public void Test_PurchaseThrowsExceptionWhenBalanceIsTooLow()
         {
             //Arrange
-
+            const string TEST_PRODUCT_ID = "1";
+            var store = purchaseMethodSetupSingleUserSingleProduct(1.00, TEST_PRODUCT_ID, 1.01, 10);
             //Act
-
+            try
+            {
+                store.Purchase(TEST_PRODUCT_ID, 1);
+            }
             //Assert
+            catch(InsufficientFundsException ife)
+            {
+                Assert.IsTrue(true);
+            }
+
+            Assert.Fail();
+            
         }
 
         [Test]
         public void Test_PurchaseThrowsExceptionWhenBalanceIsTooLowVersion2()
         {
             //Arrange
+            const string TEST_PRODUCT_ID = "1";
+            var store = purchaseMethodSetupSingleUserSingleProduct(1.00, TEST_PRODUCT_ID, 1.01, 10);
+            //Act
 
+            //Assert
+            Assert.That(() => store.Purchase(TEST_PRODUCT_ID, 1), 
+                Throws.Exception
+                .TypeOf<InsufficientFundsException>());
+        }
+
+        [Test]
+        public void Test_PurchaseThrowsExceptionWhenQuantityTooLow()
+        {
+            //Arrange
+            const string TEST_PRODUCT_ID = "1";
+            var store = purchaseMethodSetupSingleUserSingleProduct(99.99, TEST_PRODUCT_ID, 9.99, 1);
             //Act
 
             //Assert
+            Assert.That(() => store.Purchase(TEST_PRODUCT_ID, 2),
+                Throws.Exception
+                .TypeOf<OutOfStockException>());
         }
 
 
@@ -108,6 +149,7 @@ public void Test_Initialize()
         }
 
 
+
         [TearDown]
         public void Test_Cleanup()
         {
diff --git a/UnitTestProject/UnitTestProject.csproj b/UnitTestProject/UnitTestProject.csproj
index bcf3847..81e158c 100644
--- a/UnitTestProject/UnitTestProject.csproj
+++ b/UnitTestProject/UnitTestProject.csproj
@@ -35,6 +35,7 @@
     <WarningLevel>4</WarningLevel>
   </PropertyGroup>
   <ItemGroup>
+    <Reference Include="Microsoft.VisualStudio.QualityTools.UnitTestFramework, Version=10.0.0.0, Culture=neutral, PublicKeyToken=b03f5f7f11d50a3a, processorArchitecture=MSIL" />
     <Reference Include="Newtonsoft.Json, Version=8.0.0.0, Culture=neutral, PublicKeyToken=30ad4fe6b2a6aeed, processorArchitecture=MSIL">
       <HintPath>..\packages\Newtonsoft.Json.8.0.2\lib\net45\Newtonsoft.Json.dll</HintPath>
       <Private>True</Private>
@@ -70,6 +71,7 @@
     <Otherwise />
   </Choose>
   <ItemGroup>
+    <Compile Include="AuthenticatorTests.cs" />
     <Compile Include="StoreTests.cs" />
     <Compile Include="IntegrationTests.cs" />
     <Compile Include="Properties\AssemblyInfo.cs" />