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..281ec05
--- /dev/null
+++ b/UnitTestProject/AuthenticatorTests.cs
@@ -0,0 +1,52 @@
+using System.Security.Cryptography.X509Certificates;
+using Newtonsoft.Json;
+using NUnit.Framework;
+using Refactoring;
+using System;
+using System.Collections.Generic;
+using System.IO;
+using System.Linq;
+
+namespace UnitTestProject
+{
+    [TestFixture]
+    class AuthenticatorTests
+    {
+        private User createTestUser(string name, string password, double balance)
+        {
+            var testUser = new User {Name = name, Password = password, Balance = balance};
+
+            return testUser;
+        }
+
+        [Test]
+        public void Test_ShouldAuthenticateUser()
+        {
+            //Arrange
+            var users = new List<User> { createTestUser("Unit Test", "", 100.00) };
+            var authenticate = new Authenticator(users);
+
+            //Act
+            var user = authenticate.Authenticate(users.ToList().Select(r => r.Name).First(),
+                users.ToList().Select(r => r.Password).First());
+
+            //Assert
+            Assert.IsNotNull(user);
+        }
+
+        [Test]
+        public void Test_ShouldReturnNull()
+        {
+            //Arrange
+            var users = new List<User> { createTestUser("Unit Test", "", 100.00) };
+            var authenticate = new Authenticator(users);
+
+            //Act
+            var user = authenticate.Authenticate("",
+                users.ToList().Select(r => r.Password).First());
+
+            //Assert
+            Assert.IsNull(user);
+        }    
+    }
+}
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..6e55594 100644
--- a/UnitTestProject/StoreTests.cs
+++ b/UnitTestProject/StoreTests.cs
@@ -15,21 +15,14 @@ class StoreTests
     {
         private User createTestUser(string name, string password, double balance)
         {
-            User testUser = new User();
-            testUser.Name = name;
-            testUser.Password = password;
-            testUser.Balance = balance;
+            var testUser = new User {Name = name, Password = password, Balance = balance};
 
             return testUser;
         }
 
         private Product createTestProduct(string id, string name, double price, int quantity)
         {
-            Product testProduct = new Product();
-            testProduct.Id = id;
-            testProduct.Name = name;
-            testProduct.Price = price;
-            testProduct.Quantity = quantity;
+            var testProduct = new Product {Id = id, Name = name, Price = price, Quantity = quantity};
 
             return testProduct;
         }
@@ -60,36 +53,116 @@ public void Test_PurchaseThrowsNoErrorForValidFunds()
         public void Test_PurchaseRemovesProductFromStore()
         {
             //Arrange
+            const string TEST_PRODUCT_ID = "2";
 
+            var users = new List<User> {createTestUser("Unit Test", "", 100.00)};
+            var products = new List<Product> {createTestProduct(TEST_PRODUCT_ID, "MyProduct", 5.00, 10)};
+            var dataManager = new DataManager(users, products);
+            var store = new Store(users.ToList().First(), dataManager);
+            
             //Act
+            store.Purchase(TEST_PRODUCT_ID,9);
 
             //Assert 
             //(choose the appropriate statement(s))
-            //Assert.AreEqual(1, products[0].Quantity);
+            Assert.AreEqual(1, products[0].Quantity);
             //Assert.AreSame(1, products[0].Quantity);
-            //Assert.IsTrue(products[0].Quantity == 1);
+            Assert.IsTrue(products[0].Quantity == 1);
         }
 
         [Test]
         public void Test_PurchaseThrowsExceptionWhenBalanceIsTooLow()
         {
             //Arrange
+            const string TEST_PRODUCT_ID = "2";
+            const string INSUFFICIENT_FUND_EXCEPTION =
+                "Exception of type 'Refactoring.InsufficientFundsException' was thrown.";
 
-            //Act
+            var users = new List<User> { createTestUser("Unit Test", "", 1.00) };
+            var products = new List<Product> { createTestProduct(TEST_PRODUCT_ID, "MyProduct", 5.00, 10) };
+            var dataManager = new DataManager(users, products);
+            var store = new Store(users.ToList().First(), dataManager);
+
+            try
+            {
+                //Act
+                store.Purchase(TEST_PRODUCT_ID, 9);
+            }
+            catch (Exception e)
+            {
+                Assert.AreEqual(INSUFFICIENT_FUND_EXCEPTION, e.Message);
+            }
 
-            //Assert
         }
 
         [Test]
         public void Test_PurchaseThrowsExceptionWhenBalanceIsTooLowVersion2()
         {
             //Arrange
+            const string TEST_PRODUCT_ID = "2";
+
+            var users = new List<User> { createTestUser("Unit Test", "", 1.00) };
+            var products = new List<Product> { createTestProduct(TEST_PRODUCT_ID, "MyProduct", 5.00, 1) };
+            var dataManager = new DataManager(users, products);
+            var store = new Store(users.ToList().First(), dataManager);
 
             //Act
+            Assert.Throws<InsufficientFundsException>(() => store.Purchase(TEST_PRODUCT_ID, 9));
+        }
+
+
+        [Test]
+        public void Test_ShouldThrowOutOfStockException()
+        {
+            //Arrange
+            Store store;
+            var TEST_PRODUCT_ID = InitialSetup(out store);            
+            //Act
+            Assert.Throws<OutOfStockException>(() => store.Purchase(TEST_PRODUCT_ID, 3));
 
-            //Assert
         }
 
+        [Test]
+        public void Test_ShouldReturnProductList()
+        {
+            //Arrange
+            Store store;
+            var TEST_PRODUCT_ID = InitialSetup(out store);            
+            //Act
+            Assert.IsNotNullOrEmpty(store.GetProductList());
+        }
+
+        [Test]
+        public void Test_ShouldReturnNumberOfProducts()
+        {
+            //Arrange
+            Store store;
+            var TEST_PRODUCT_ID = InitialSetup(out store);
+            //Act
+            Assert.IsNotNullOrEmpty(store.NumberOfProducts().ToString());
+        }
+
+        [Test]
+        public void Test_ShouldContainsProduct()
+        {
+            Store store;
+            var TEST_PRODUCT_ID = InitialSetup(out store);
+
+            //Act
+            Assert.IsTrue(store.ContainsProduct(TEST_PRODUCT_ID));
+        }
+
+        private string InitialSetup(out Store store)
+        {
+            //Arrange
+            const string TEST_PRODUCT_ID = "2";
+
+            var users = new List<User> {createTestUser("Unit Test", "", 100.00)};
+            var products = new List<Product> {createTestProduct(TEST_PRODUCT_ID, "MyProduct", 5.00, 1)};
+            var dataManager = new DataManager(users, products);
+            store = new Store(users.ToList().First(), dataManager);
+            return TEST_PRODUCT_ID;
+        }
 
         // 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
diff --git a/UnitTestProject/UnitTestProject.csproj b/UnitTestProject/UnitTestProject.csproj
index bcf3847..1a9e337 100644
--- a/UnitTestProject/UnitTestProject.csproj
+++ b/UnitTestProject/UnitTestProject.csproj
@@ -70,6 +70,7 @@
     <Otherwise />
   </Choose>
   <ItemGroup>
+    <Compile Include="AuthenticatorTests.cs" />
     <Compile Include="StoreTests.cs" />
     <Compile Include="IntegrationTests.cs" />
     <Compile Include="Properties\AssemblyInfo.cs" />