refactored the code for Unit testing and added unit test cases along …

dot-net/UnitTesting/WriteUnitTest.UnitTests/Services/LessonServiceUnitTests.cs

@@ -1,13 +1,92 @@
-using Microsoft.VisualStudio.TestTools.UnitTesting;
+using System;
+using System.Collections.Generic;
+using FakeItEasy;
+using NUnit.Framework;
+using WriteUnitTest.Entities;
+using WriteUnitTest.Repositories;
+using WriteUnitTest.Services;
 
 namespace WriteUnitTest.UnitTests.Services
 {
-    [TestClass]
+    [TestFixture]
     public class LessonServiceUnitTests
     {
-        [TestMethod]
-        public void UpdateLessonGrade_Test()
+        private ILessonService _lessonService;
+        private ILessonRepository _lessonRepository;
+        private IModuleRepository _moduleRepository;
+
+        [SetUp]
+        public void Init()
+        {
+            _lessonRepository = A.Fake<ILessonRepository>();
+            _moduleRepository = A.Fake<IModuleRepository>();
+            _lessonService = new LessonService(_lessonRepository, _moduleRepository);
+        }
+
+        [Test]
+        public void when_passing_valid_lessonid_update_lesson_grade()
+        {
+            const int lessonId = 12;
+            const double grade = 63.7d;
+            var fakeLesson = new Lesson
+            {
+                Grade = grade,
+                IsPassed = false,
+                LessonId = lessonId
+            };
+            //Arrange
+            A.CallTo(() => _lessonRepository.GetLesson(lessonId)).Returns(fakeLesson);
+            A.CallTo(() => _moduleRepository.GetModule(lessonId)).Returns(new Module
+            {
+                Lessons = new List<Lesson>{ fakeLesson },
+                MinimumPassingGrade = 80,
+                ModuleId = 873
+            });
+
+            //Act
+            _lessonService.UpdateLessonGrade(lessonId, grade);
+
+            //Assert
+            A.CallTo(() => _lessonRepository.GetLesson(A<int>.Ignored)).MustHaveHappenedOnceExactly();
+            A.CallTo(() => _moduleRepository.GetModule(A<int>.Ignored)).MustHaveHappenedOnceExactly();
+        }
+
+        [Test]
+        public void when_passing_invalid_lessonid_to_lesson_throws_exception()
+        {
+            const int lessonId = 20;
+            const double grade = 20.5d;
+            //Arrange
+            A.CallTo(() => _lessonRepository.GetLesson(lessonId)).Returns(null);
+
+            //Act
+
+            //Assert
+            Assert.Throws<NullReferenceException>(() => _lessonService.UpdateLessonGrade(lessonId, grade));
+            A.CallTo(() => _lessonRepository.GetLesson(A<int>.Ignored)).MustHaveHappenedOnceExactly();
+            A.CallTo(() => _moduleRepository.GetModule(A<int>.Ignored)).MustNotHaveHappened();
+        }
+
+        [Test]
+        public void when_passing_invalid_lessonid_to_module_throws_exception()
         {
+            //Arrange
+            const int lessonId = 20;
+            const double grade = 20.5d;
+            A.CallTo(() => _lessonRepository.GetLesson(lessonId)).Returns(new Lesson
+            {
+                Grade = grade,
+                IsPassed = false,
+                LessonId = lessonId
+            });
+            A.CallTo(() => _moduleRepository.GetModule(lessonId)).Returns(null);
+
+            //Act
+
+            //Assert
+            Assert.Throws<NullReferenceException>(() => _lessonService.UpdateLessonGrade(lessonId, grade));
+            A.CallTo(() => _lessonRepository.GetLesson(A<int>.Ignored)).MustHaveHappenedOnceExactly();
+            A.CallTo(() => _moduleRepository.GetModule(A<int>.Ignored)).MustHaveHappenedOnceExactly();
         }
     }
 }

dot-net/UnitTesting/WriteUnitTest.UnitTests/WriteUnitTest.UnitTests.csproj

@@ -1,5 +1,6 @@
 <?xml version="1.0" encoding="utf-8"?>
 <Project ToolsVersion="14.0" DefaultTargets="Build" xmlns="http://schemas.microsoft.com/developer/msbuild/2003">
+  <Import Project="..\packages\NUnit.3.11.0\build\NUnit.props" Condition="Exists('..\packages\NUnit.3.11.0\build\NUnit.props')" />
   <PropertyGroup>
     <Configuration Condition=" '$(Configuration)' == '' ">Debug</Configuration>
     <Platform Condition=" '$(Platform)' == '' ">AnyCPU</Platform>
@@ -16,6 +17,8 @@
     <ReferencePath>$(ProgramFiles)\Common Files\microsoft shared\VSTT\$(VisualStudioVersion)\UITestExtensionPackages</ReferencePath>
     <IsCodedUITest>False</IsCodedUITest>
     <TestProjectType>UnitTest</TestProjectType>
+    <NuGetPackageImportStamp>
+    </NuGetPackageImportStamp>
   </PropertyGroup>
   <PropertyGroup Condition=" '$(Configuration)|$(Platform)' == 'Debug|AnyCPU' ">
     <DebugSymbols>true</DebugSymbols>
@@ -35,6 +38,12 @@
     <WarningLevel>4</WarningLevel>
   </PropertyGroup>
   <ItemGroup>
+    <Reference Include="FakeItEasy, Version=5.0.0.0, Culture=neutral, PublicKeyToken=eff28e2146d5fd2c, processorArchitecture=MSIL">
+      <HintPath>..\packages\FakeItEasy.5.1.1\lib\net45\FakeItEasy.dll</HintPath>
+    </Reference>
+    <Reference Include="nunit.framework, Version=3.11.0.0, Culture=neutral, PublicKeyToken=2638cd05610744eb, processorArchitecture=MSIL">
+      <HintPath>..\packages\NUnit.3.11.0\lib\net45\nunit.framework.dll</HintPath>
+    </Reference>
     <Reference Include="System" />
   </ItemGroup>
   <Choose>
@@ -55,6 +64,15 @@
     <Compile Include="Services\LessonServiceUnitTests.cs" />
     <Compile Include="Properties\AssemblyInfo.cs" />
   </ItemGroup>
+  <ItemGroup>
+    <None Include="packages.config" />
+  </ItemGroup>
+  <ItemGroup>
+    <ProjectReference Include="..\WriteUnitTest\WriteUnitTest.csproj">
+      <Project>{00A40A05-8314-4F25-A444-46DDEAC3497E}</Project>
+      <Name>WriteUnitTest</Name>
+    </ProjectReference>
+  </ItemGroup>
   <Choose>
     <When Condition="'$(VisualStudioVersion)' == '10.0' And '$(IsCodedUITest)' == 'True'">
       <ItemGroup>
@@ -75,6 +93,12 @@
   </Choose>
   <Import Project="$(VSToolsPath)\TeamTest\Microsoft.TestTools.targets" Condition="Exists('$(VSToolsPath)\TeamTest\Microsoft.TestTools.targets')" />
   <Import Project="$(MSBuildToolsPath)\Microsoft.CSharp.targets" />
+  <Target Name="EnsureNuGetPackageBuildImports" BeforeTargets="PrepareForBuild">
+    <PropertyGroup>
+      <ErrorText>This project references NuGet package(s) that are missing on this computer. Use NuGet Package Restore to download them.  For more information, see http://go.microsoft.com/fwlink/?LinkID=322105. The missing file is {0}.</ErrorText>
+    </PropertyGroup>
+    <Error Condition="!Exists('..\packages\NUnit.3.11.0\build\NUnit.props')" Text="$([System.String]::Format('$(ErrorText)', '..\packages\NUnit.3.11.0\build\NUnit.props'))" />
+  </Target>
   <!-- To modify your build process, add your task inside one of the targets below and uncomment it. 
        Other similar extension points exist, see Microsoft.Common.targets.
   <Target Name="BeforeBuild">

dot-net/UnitTesting/WriteUnitTest.UnitTests/packages.config

@@ -0,0 +1,5 @@
+<?xml version="1.0" encoding="utf-8"?>
+<packages>
+  <package id="FakeItEasy" version="5.1.1" targetFramework="net461" />
+  <package id="NUnit" version="3.11.0" targetFramework="net461" />
+</packages>

dot-net/UnitTesting/WriteUnitTest/INSTRUCTIONS.txt

@@ -30,4 +30,13 @@ Background Information:
 		written and run by software developers to ensure that code meets its design 
 		and behaves as intended.
 
-		Module - a collection of lessons 
+		Module - a collection of lessons
+
+
+ Design Decision:
+	I have added interfaces for each class LessonRepository, ModuelRepository and LessonService 
+	to help me implementing Dependency Injection DI. rather than directly instantiating dependencies,
+	or the objects that are needed for class to perform its operation are provided to the class
+	in abstracted way. It reduces dependencies and our code is loosely coupled. This helps in unit
+	testing our code and following the TDD approach. 
+		I have added unit test cases by using NUnit and FakeItEasy framework 

dot-net/UnitTesting/WriteUnitTest/Program.cs

@@ -1,12 +1,13 @@
-using WriteUnitTest.Services;
+using WriteUnitTest.Repositories;
+using WriteUnitTest.Services;
 
 namespace WriteUnitTest
 {
     public class Program
     {
         public static void Main(string[] args)
         {
-            var lessonSvc = new LessonService();
+            var lessonSvc = new LessonService(new LessonRepository(), new ModuleRepository());
 
             var lessonId = 12;
 

dot-net/UnitTesting/WriteUnitTest/Repositories/ILessonRepository.cs

@@ -0,0 +1,14 @@
+using System;
+using System.Collections.Generic;
+using System.Linq;
+using System.Text;
+using System.Threading.Tasks;
+using WriteUnitTest.Entities;
+
+namespace WriteUnitTest.Repositories
+{
+    public interface ILessonRepository
+    {
+        Lesson GetLesson(int lessonId);
+    }
+}

dot-net/UnitTesting/WriteUnitTest/Repositories/IModuleRepository.cs

@@ -0,0 +1,14 @@
+using System;
+using System.Collections.Generic;
+using System.Linq;
+using System.Text;
+using System.Threading.Tasks;
+using WriteUnitTest.Entities;
+
+namespace WriteUnitTest.Repositories
+{
+    public interface IModuleRepository
+    {
+        Module GetModule(int lessonId);
+    }
+}

dot-net/UnitTesting/WriteUnitTest/Repositories/LessonRepository.cs

@@ -4,13 +4,13 @@
 
 namespace WriteUnitTest.Repositories
 {
-    public class LessonRepository
+    public class LessonRepository : ILessonRepository
     {
-        private readonly List<Lesson> lessonList;
+        private readonly List<Lesson> _lessonList;
 
         public LessonRepository()
         {
-            lessonList = new List<Lesson>
+            _lessonList = new List<Lesson>
             {
                 new Lesson
                 {
@@ -29,7 +29,7 @@ public LessonRepository()
 
         public Lesson GetLesson(int lessonId)
         {
-            return lessonList.FirstOrDefault(x => x.LessonId == lessonId);
+            return _lessonList.FirstOrDefault(x => x.LessonId == lessonId);
         }
     }
 }

dot-net/UnitTesting/WriteUnitTest/Repositories/ModuleRepository.cs

@@ -4,13 +4,13 @@
 
 namespace WriteUnitTest.Repositories
 {
-    public class ModuleRepository
+    public class ModuleRepository : IModuleRepository
     {
-        private readonly List<Module> moduleList;
+        private readonly List<Module> _moduleList;
 
         public ModuleRepository()
         {
-            moduleList = new List<Module>
+            _moduleList = new List<Module>
             {
                 new Module
                 {
@@ -37,7 +37,7 @@ public ModuleRepository()
 
         public Module GetModule(int lessonId)
         {
-            return moduleList.FirstOrDefault(x => x.Lessons.Any(y => y.LessonId == lessonId));
+            return _moduleList.FirstOrDefault(x => x.Lessons.Any(y => y.LessonId == lessonId));
         }
     }
 }

dot-net/UnitTesting/WriteUnitTest/Services/ILessonService.cs

@@ -0,0 +1,13 @@
+using System;
+using System.Collections.Generic;
+using System.Linq;
+using System.Text;
+using System.Threading.Tasks;
+
+namespace WriteUnitTest.Services
+{
+    public interface ILessonService
+    {
+        void UpdateLessonGrade(int lessonId, double grade);
+    }
+}

dot-net/UnitTesting/WriteUnitTest/Services/LessonService.cs

@@ -1,34 +1,29 @@
-using WriteUnitTest.Repositories;
+using System;
+using WriteUnitTest.Repositories;
 
 namespace WriteUnitTest.Services
 {
-    public class LessonService
+    public class LessonService : ILessonService
     {
-        public LessonService()
+        private readonly ILessonRepository _lessonRepository;
+        private readonly IModuleRepository _moduleRepository;
+        public LessonService(ILessonRepository lessonRepository, IModuleRepository moduleRepository)
         {
+            _lessonRepository = lessonRepository;
+            _moduleRepository = moduleRepository;
         }
 
         public void UpdateLessonGrade(int lessonId, double grade)
         {
-            var lessonRepo = new LessonRepository();
-            var lesson = lessonRepo.GetLesson(lessonId);
-
+            var lesson = _lessonRepository.GetLesson(lessonId);
+            if (lesson == null) throw new NullReferenceException();
             lesson.Grade = grade;
 
-            if (!lesson.IsPassed)
-            {
-                var moduleRepository = new ModuleRepository();
-                var module = moduleRepository.GetModule(lessonId);
+            if (lesson.IsPassed) return;
 
-                if (grade >= module.MinimumPassingGrade)
-                {
-                    lesson.IsPassed = true;
-                }
-                else
-                {
-                    lesson.IsPassed = false;
-                }
-            }
+            var module = _moduleRepository.GetModule(lessonId);
+            if (module == null) throw new NullReferenceException();
+            lesson.IsPassed = grade >= module.MinimumPassingGrade;
         }
     }
 }

dot-net/UnitTesting/WriteUnitTest/WriteUnitTest.csproj

@@ -47,8 +47,11 @@
     <Compile Include="Entities\Module.cs" />
     <Compile Include="Program.cs" />
     <Compile Include="Properties\AssemblyInfo.cs" />
+    <Compile Include="Repositories\ILessonRepository.cs" />
+    <Compile Include="Repositories\IModuleRepository.cs" />
     <Compile Include="Repositories\LessonRepository.cs" />
     <Compile Include="Repositories\ModuleRepository.cs" />
+    <Compile Include="Services\ILessonService.cs" />
     <Compile Include="Services\LessonService.cs" />
   </ItemGroup>
   <ItemGroup>