Getting Started with Interfaces and Mocks

GettingStartedWithInterfacesAndMocks/DiceGame/Entities/Die.cs

@@ -0,0 +1,22 @@
+using GettingStartedWithInterfacesAndMocks.DiceGame.Extensions;
+using GettingStartedWithInterfacesAndMocks.DiceGame.Interfaces;
+using System;
+using System.Collections.Generic;
+using System.Text;
+
+namespace GettingStartedWithInterfacesAndMocks.DiceGame.Entities
+{
+    public class Die : IDie
+    {
+        public Die()
+        {
+            Roll();
+        }
+
+        public int Value { get; private set; }
+        public void Roll()
+        {
+            Value = DieRoller.GetD6Roll();
+        }
+    }
+}

GettingStartedWithInterfacesAndMocks/DiceGame/Extensions/DieExtensions.cs

@@ -0,0 +1,25 @@
+using GettingStartedWithInterfacesAndMocks.DiceGame.Interfaces;
+using System;
+using System.Collections.Generic;
+using System.Linq;
+
+namespace GettingStartedWithInterfacesAndMocks.DiceGame.Extensions
+{
+    public static class DieExtensions
+    {
+        public static bool IsValidRoll(this IEnumerable<IDie> dice)
+        {
+            return dice.Count() == 5;
+        }
+
+        public static bool IsFiveOfAKind(this IEnumerable<IDie> dice)
+        {
+            if (!dice.IsValidRoll())
+            {
+                throw new ArgumentException("A valid roll must contain exactly five dice");
+            }
+
+            return dice.GroupBy(d => d.Value).Count() == 1;
+        }
+    }
+}

GettingStartedWithInterfacesAndMocks/DiceGame/Extensions/DieRoller.cs

@@ -0,0 +1,22 @@
+using GettingStartedWithInterfacesAndMocks.DiceGame.Entities;
+using System;
+using System.Collections.Generic;
+using System.Linq;
+
+namespace GettingStartedWithInterfacesAndMocks.DiceGame.Extensions
+{
+    public static class DieRoller
+    {
+        static Random _rng = new Random();
+
+        public static int GetD6Roll()
+        {
+            return _rng.Next(1, 7);
+        }
+
+        public static IEnumerable<Die> GetGameRoll()
+        {
+            return Enumerable.Range(1, 5).Select(_ => new Die());
+        }
+    }
+}

GettingStartedWithInterfacesAndMocks/DiceGame/Interfaces/IDie.cs

@@ -0,0 +1,10 @@
+using System;
+
+namespace GettingStartedWithInterfacesAndMocks.DiceGame.Interfaces
+{
+    public interface IDie
+    {
+        void Roll();
+        int Value { get; }
+    }
+}

GettingStartedWithInterfacesAndMocks/GettingStartedWithInterfacesAndMocks.csproj

@@ -0,0 +1,7 @@
+<Project Sdk="Microsoft.NET.Sdk">
+
+  <PropertyGroup>
+    <TargetFramework>netcoreapp3.1</TargetFramework>
+  </PropertyGroup>
+
+</Project>

GettingStartedWithInterfacesAndMocksTests/DieExtensionsTests.cs

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+using FluentAssertions;
+using GettingStartedWithInterfacesAndMocks.DiceGame.Entities;
+using GettingStartedWithInterfacesAndMocks.DiceGame.Extensions;
+using GettingStartedWithInterfacesAndMocksTests.TestingMocks;
+using Microsoft.VisualStudio.TestTools.UnitTesting;
+using System;
+using System.Collections.Generic;
+using System.Linq;
+
+namespace GettingStartedWithInterfacesAndMocksTests
+{
+    [TestClass]
+    public class DieExtensionsTests
+    {
+        [TestMethod]
+        public void IsValidRoll_RollHas4Dice_ReturnsFalse()
+        {
+            var dice = Enumerable.Range(1, 4).Select(_ => new Die());
+
+            dice.IsValidRoll().Should().BeFalse(because: "A valid game roll has five dice");
+        }
+
+        [TestMethod]
+        public void IsValidRoll_RollHas5Dice_ReturnsTrue()
+        {
+            var dice = Enumerable.Range(1, 5).Select(_ => new Die());
+
+            dice.IsValidRoll().Should().BeTrue(because: "A valid game roll has five dice");
+        }
+
+        [TestMethod]
+        public void IsFiveOfAKind_AllDiceAreTheSame_ReturnsTrue()
+        {
+            var dice = Enumerable.Range(1, 5).Select(_ => new SettableD6(5));
+
+            dice.IsFiveOfAKind().Should().BeTrue();
+        }
+
+        [TestMethod]
+        public void IsFiveOfAKind_AllDiceAreNotTheSame_ReturnsFalse()
+        {
+            var dice = new[]{
+                new SettableD6(1),
+                new SettableD6(3),
+                new SettableD6(4),
+                new SettableD6(1),
+                new SettableD6(1)
+            };
+
+            dice.IsFiveOfAKind().Should().BeFalse();
+        }
+
+        [TestMethod]
+        public void IsFiveOfAKind_NotAValidRoll_ThrowsArgumentException()
+        {
+            var dice = new[]{
+                new SettableD6(2),
+                new SettableD6(3)
+            };
+
+            Action validateRoll = () => dice.IsFiveOfAKind();
+
+            validateRoll.Should().Throw<ArgumentException>();
+        }
+    }
+}

GettingStartedWithInterfacesAndMocksTests/GettingStartedWithInterfacesAndMocksTests.csproj

@@ -0,0 +1,21 @@
+<Project Sdk="Microsoft.NET.Sdk">
+
+  <PropertyGroup>
+    <TargetFramework>netcoreapp3.1</TargetFramework>
+
+    <IsPackable>false</IsPackable>
+  </PropertyGroup>
+
+  <ItemGroup>
+    <PackageReference Include="FluentAssertions" Version="5.9.0" />
+    <PackageReference Include="Microsoft.NET.Test.Sdk" Version="16.2.0" />
+    <PackageReference Include="MSTest.TestAdapter" Version="2.0.0" />
+    <PackageReference Include="MSTest.TestFramework" Version="2.0.0" />
+    <PackageReference Include="coverlet.collector" Version="1.0.1" />
+  </ItemGroup>
+
+  <ItemGroup>
+    <ProjectReference Include="..\GettingStartedWithInterfacesAndMocks\GettingStartedWithInterfacesAndMocks.csproj" />
+  </ItemGroup>
+
+</Project>

GettingStartedWithInterfacesAndMocksTests/TestingMocks/SettableD6.cs

@@ -0,0 +1,22 @@
+using GettingStartedWithInterfacesAndMocks.DiceGame.Interfaces;
+using System;
+using System.Collections.Generic;
+using System.Text;
+
+namespace GettingStartedWithInterfacesAndMocksTests.TestingMocks
+{
+    public class SettableD6 : IDie
+    {
+        public SettableD6(int value)
+        {
+            Value = value;
+        }
+
+        public int Value { get; set; }
+
+        public void Roll()
+        {
+            //Does nothing
+        }
+    }
+}

TestingPracticesWithExamples.sln

@@ -3,22 +3,34 @@ Microsoft Visual Studio Solution File, Format Version 12.00
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+Project("{2150E333-8FDC-42A3-9474-1A3956D46DE8}") = "InterfacesAndMocks", "InterfacesAndMocks", "{42786B9F-B4BA-4D56-8104-D359C5E0E917}"
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