Added Test examples and code complexity

SampleTests/OrderLogicTests.cs

@@ -0,0 +1,72 @@
+using Moq;
+using Samples.BlanketsHoldingNoHeat;
+using System;
+using System.Collections.Generic;
+using System.Linq;
+using System.Text;
+using System.Threading.Tasks;
+using Xunit;
+
+namespace SampleTests
+{
+    public class OrderLogicTests
+    {
+        [Fact]
+        public async Task WhenValidationErrorsExist_ReturnsErrorsAndDoesNotSave()
+        {
+            //arrange
+            Mock<IOrderValidator> mockValidator = new Mock<IOrderValidator>();
+            Mock<IOrderProvider> mockProvider = new Mock<IOrderProvider>();
+            Mock<ILogger> mockLogger = new Mock<ILogger>();
+
+            mockValidator.Setup(v => v.ValidateOrder(It.IsAny<Order>()))
+                .ReturnsAsync(new OrderValidationError[] {
+                new OrderValidationError()
+                {
+                    Message = "Live long and prosper"
+                }
+                });
+            var logicUnderTest = new OrderLogic(
+                mockValidator.Object,
+                mockProvider.Object,
+                mockLogger.Object);
+
+            //act
+            var result = await logicUnderTest.PlaceOrder(new Order());
+
+            //assert
+            mockLogger.Verify(l => l.Log(It.IsAny<string>()));
+            Assert.Single(result);
+            var error = result.First();
+            Assert.Equal("Live long and prosper", error.Message);
+
+            mockProvider.Verify(p => p.SaveOrder(It.IsAny<Order>()), Times.Never);
+        }
+
+        [Fact]
+        public async Task WhenNoValidationErrors_SavesOrder()
+        {
+            //arrange
+            Mock<IOrderValidator> mockValidator = new Mock<IOrderValidator>();
+            Mock<IOrderProvider> mockProvider = new Mock<IOrderProvider>();
+            Mock<ILogger> mockLogger = new Mock<ILogger>();
+
+            mockValidator.Setup(v => v.ValidateOrder(It.IsAny<Order>()))
+                .ReturnsAsync(Enumerable.Empty<OrderValidationError>());
+
+            var fakeOrder = new Order();
+
+            var logicUnderTest = new OrderLogic(
+                mockValidator.Object,
+                mockProvider.Object,
+                mockLogger.Object);
+
+            //act
+            var result = await logicUnderTest.PlaceOrder(fakeOrder);
+
+            //assert
+            Assert.Empty(result);
+            mockProvider.Verify(p => p.SaveOrder(fakeOrder), Times.Once);
+        }
+    }
+}

SampleTests/SampleTests.csproj

@@ -0,0 +1,20 @@
+<Project Sdk="Microsoft.NET.Sdk">
+
+  <PropertyGroup>
+    <TargetFramework>netcoreapp3.1</TargetFramework>
+  </PropertyGroup>
+
+  <ItemGroup>
+    <PackageReference Include="Microsoft.NET.Test.Sdk" Version="16.8.0" />
+    <PackageReference Include="xunit" Version="2.4.1" />
+    <PackageReference Include="xunit.runner.visualstudio" Version="2.4.3">
+      <PrivateAssets>all</PrivateAssets>
+      <IncludeAssets>runtime; build; native; contentfiles; analyzers; buildtransitive</IncludeAssets>
+    </PackageReference>
+  </ItemGroup>
+
+  <ItemGroup>
+    <ProjectReference Include="..\Samples\Samples.csproj" />
+  </ItemGroup>
+
+</Project>

Samples/BlanketsHoldingNoHeat/Interfaces.cs

@@ -0,0 +1,34 @@
+using System;
+using System.Collections.Generic;
+using System.Text;
+using System.Threading.Tasks;
+
+namespace Samples.BlanketsHoldingNoHeat
+{
+    public interface IOrderLogic
+    {
+        Task<IEnumerable<OrderValidationError>> PlaceOrder(Order order);
+    }
+
+    public interface IOrderValidator
+    {
+        Task<IEnumerable<OrderValidationError>> ValidateOrder(Order order);
+    }
+
+    public class OrderValidationError
+    {
+        public string Message { get; set; }
+    }
+
+    public interface ILogger
+    {
+        void Log(string message);
+    }
+
+    public interface IOrderProvider
+    {
+        Task SaveOrder(Order order);
+    }
+
+}
+

Samples/BlanketsHoldingNoHeat/Order.cs

@@ -0,0 +1,10 @@
+using System;
+using System.Collections.Generic;
+using System.Text;
+
+namespace Samples.BlanketsHoldingNoHeat
+{
+    public class Order
+    {
+    }
+}

Samples/BlanketsHoldingNoHeat/OrderLogic.cs

@@ -0,0 +1,35 @@
+using System.Collections.Generic;
+using System.Linq;
+using System.Threading.Tasks;
+
+namespace Samples.BlanketsHoldingNoHeat
+{
+    public class OrderLogic : IOrderLogic
+    {
+        readonly IOrderValidator _validator;
+        readonly IOrderProvider _orderProvider;
+        readonly ILogger _logger;
+
+        public OrderLogic(IOrderValidator validator, IOrderProvider orderProvider, ILogger logger)
+        {
+            _validator = validator;
+            _orderProvider = orderProvider;
+            _logger = logger;
+        }
+
+        public async Task<IEnumerable<OrderValidationError>> PlaceOrder(Order order)
+        {
+            var errors = await _validator.ValidateOrder(order);
+
+            if (errors.Any())
+            {
+                _logger.Log("Cannot process order");
+                return errors;
+            }
+
+            await _orderProvider.SaveOrder(order);
+
+            return errors;
+        }
+    }
+}

Samples/BlanketsHoldingNoHeat/OrderLogic/PlaceOrderTests.cs

@@ -0,0 +1,46 @@
+//using Moq;
+//using System;
+//using System.Collections.Generic;
+//using System.Linq;
+//using System.Text;
+//using System.Threading.Tasks;
+//using Xunit;
+
+//namespace Samples.BlanketsHoldingNoHeat.OrderLogicTests
+//{
+
+//    public class PlaceOrderTests
+//    {
+//        [Fact]
+//        public async Task WhenValidationErrorsExist_ReturnsErrorsAndDoesNotSave()
+//        {
+//            //arrange
+//            Mock<IOrderValidator> mockValidator = new Mock<IOrderValidator>();
+//            Mock<IOrderProvider> mockProvider = new Mock<IOrderProvider>();
+//            Mock<ILogger> mockLogger = new Mock<ILogger>();
+
+//            mockValidator.Setup(v => v.ValidateOrder(It.IsAny<Order>()))
+//                .ReturnsAsync(new OrderValidationError[] {
+//        new OrderValidationError()
+//        {
+//            Message = "Live long and prosper"
+//        }
+//                });
+//            var logicUnderTest = new OrderLogic(
+//                mockValidator.Object,
+//                mockProvider.Object,
+//                mockLogger.Object);
+
+//            //act
+//            var result = await logicUnderTest.PlaceOrder(new Order());
+
+//            //assert
+//            mockLogger.Verify(l => l.Log(It.IsAny<string>()));
+//            Assert.Single(result);
+//            var error = result.First();
+//            Assert.Equal("Live long and prosper", error.Message);
+
+//            mockProvider.Verify(p => p.SaveOrder(It.IsAny<Order>()), Times.Never);
+//        }
+//    }
+//}

Samples/OofOne/Examples.cs

@@ -0,0 +1,104 @@
+using System;
+using System.Collections.Generic;
+using System.Linq;
+using System.Text;
+
+namespace Samples.OofOne
+{
+    class Examples
+    {
+        readonly ICategoryProvider _categoryProvider;
+        readonly IBookProvider _bookProvider;
+
+        IEnumerable<Category> GetCategoriesFromBooks(
+            IEnumerable<Book> books,
+            IEnumerable<Category> categories)
+        {
+            List<Category> usedCategories = new List<Category>();
+
+            foreach (var book in books)
+            {
+                foreach (var catId in book.CategoryIds)
+                {
+                    var category = categories.FirstOrDefault(c => c.ID == catId);
+                    if (category != null &&
+                        usedCategories.Any(uc => uc.ID == category.ID))
+                    {
+                        usedCategories.Add(category);
+                    }
+                }
+            }
+            return usedCategories;
+        }
+
+        IEnumerable<Category> GetCategoriesFromBooks2(
+            IEnumerable<Book> books,
+            IEnumerable<Category> categories)
+        {
+            var usedCategoryIds = books.SelectMany(b => b.CategoryIds);
+            var categoryHash = new HashSet<int>(usedCategoryIds);
+
+            foreach (var category in categories)
+            {
+                if (categoryHash.Contains(category.ID))
+                {
+                    yield return category;
+                }
+            }
+        }
+
+        public IEnumerable<Book> GetRelatedBooks(Book book)
+        {
+            Dictionary<Book, int> bookCounts = new Dictionary<Book, int>();
+            foreach (var cat in _categoryProvider.GetCategories(book))
+            {
+                var categories = _bookProvider.GetBooksInCategory(cat.ID);
+                UpdateBookCounts(bookCounts, categories);
+            }
+
+            return bookCounts.OrderBy(kvp => kvp.Value).Select(kvp => kvp.Key);
+        }
+
+        private static void UpdateBookCounts(
+            Dictionary<Book, int> bookCounts, IEnumerable<Book> books)
+        {
+            foreach (var relatedBook in books)
+            {
+                if (bookCounts.ContainsKey(relatedBook))
+                {
+                    bookCounts[relatedBook] = bookCounts[relatedBook] + 1;
+                }
+                else
+                {
+                    bookCounts[relatedBook] = 1;
+                }
+            }
+        }
+    }
+
+
+    public interface ICategoryProvider
+    {
+        IEnumerable<Category> GetCategories(Book book);
+    }
+
+    public interface IBookProvider
+    {
+        Book GetById(int id);
+        IEnumerable<Book> GetBooksInCategory(int catId);
+    }
+
+    public class Book
+    {
+        public int ID { get; set; }
+        public string Title { get; set; }
+        public IEnumerable<int> CategoryIds { get; set; }
+    }
+
+    public class Category
+    {
+        public int ID { get; set; }
+        public string Name { get; set; }
+
+    }
+}

Samples/Samples.csproj

@@ -4,4 +4,13 @@
     <TargetFramework>netcoreapp3.1</TargetFramework>
   </PropertyGroup>
 
+  <ItemGroup>
+    <PackageReference Include="Moq" Version="4.15.1" />
+    <PackageReference Include="xunit" Version="2.4.1" />
+    <PackageReference Include="xunit.runner.visualstudio" Version="2.4.3">
+      <PrivateAssets>all</PrivateAssets>
+      <IncludeAssets>runtime; build; native; contentfiles; analyzers; buildtransitive</IncludeAssets>
+    </PackageReference>
+  </ItemGroup>
+
 </Project>

TaoOfCode.sln

@@ -5,7 +5,9 @@ VisualStudioVersion = 16.0.30711.63
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 Project("{9A19103F-16F7-4668-BE54-9A1E7A4F7556}") = "Samples", "Samples\Samples.csproj", "{F4CC7DE2-E690-470F-B697-DE1B2CBA0187}"
 EndProject
-Project("{FAE04EC0-301F-11D3-BF4B-00C04F79EFBC}") = "CsvProcessor", "CsvProcessor\CsvProcessor.csproj", "{763A0AEC-9975-462C-939A-9F106718B678}"
+Project("{9A19103F-16F7-4668-BE54-9A1E7A4F7556}") = "CsvProcessor", "CsvProcessor\CsvProcessor.csproj", "{763A0AEC-9975-462C-939A-9F106718B678}"
+EndProject
+Project("{FAE04EC0-301F-11D3-BF4B-00C04F79EFBC}") = "SampleTests", "SampleTests\SampleTests.csproj", "{998DA7AB-6D21-4D71-91CA-906A7DD4CE4D}"
 EndProject
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 	GlobalSection(SolutionConfigurationPlatforms) = preSolution
@@ -21,6 +23,10 @@ Global
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 		{763A0AEC-9975-462C-939A-9F106718B678}.Release|Any CPU.Build.0 = Release|Any CPU
+		{998DA7AB-6D21-4D71-91CA-906A7DD4CE4D}.Debug|Any CPU.ActiveCfg = Debug|Any CPU
+		{998DA7AB-6D21-4D71-91CA-906A7DD4CE4D}.Debug|Any CPU.Build.0 = Debug|Any CPU
+		{998DA7AB-6D21-4D71-91CA-906A7DD4CE4D}.Release|Any CPU.ActiveCfg = Release|Any CPU
+		{998DA7AB-6D21-4D71-91CA-906A7DD4CE4D}.Release|Any CPU.Build.0 = Release|Any CPU
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