UsingExceptInCSharp: .NET 10, MSTest 4 and ExceptBy

csharp-linq/UsingExceptInCSharp/UsingExceptInCSharp/Employee.cs

@@ -1,9 +1,9 @@
-namespace UsingExceptInCSharp;
+namespace UsingExceptInCSharp;
 
 public class Employee
 {
     public int ID { get; set; }
-    public string Name { get; set; }
+    public string Name { get; set; } = string.Empty;
     public int Age { get; set; }
-    public string Department { get; set; }
-}
+    public string Department { get; set; } = string.Empty;
+}

csharp-linq/UsingExceptInCSharp/UsingExceptInCSharp/EmployeeComparer.cs

@@ -1,5 +1,3 @@
-using System.Diagnostics.CodeAnalysis;
-
 namespace UsingExceptInCSharp;
 
 public class EmployeeComparer : IEqualityComparer<Employee>
@@ -12,11 +10,5 @@ public bool Equals(Employee? x, Employee? y)
         return x.ID == y.ID && x.Name == y.Name && x.Age == y.Age && x.Department == y.Department;
     }
 
-    public int GetHashCode([DisallowNull] Employee obj)
-    {
-        var hashID = obj.ID.GetHashCode();
-        var hashName = obj.Name.GetHashCode();
-
-        return hashID ^ hashName;
-    }
-}
+    public int GetHashCode(Employee obj) => HashCode.Combine(obj.ID, obj.Name);
+}

csharp-linq/UsingExceptInCSharp/UsingExceptInCSharp/EmployeeRecord.cs

@@ -0,0 +1,3 @@
+namespace UsingExceptInCSharp;
+
+public record EmployeeRecord(int ID, string Name, int Age, string Department);

csharp-linq/UsingExceptInCSharp/UsingExceptInCSharp/ExceptMethodExamples.cs

@@ -31,6 +31,27 @@ public List<Employee> GetEmployeesNotInSales()
         return empNotInSales;
     }
 
+    public List<int> GetDistinctDifference()
+    {
+        int[] first = [1, 1, 2, 3, 3, 4];
+        int[] second = [3];
+
+        return first.Except(second).ToList();
+    }
+
+    public List<Employee> GetEmployeesNotInSalesFromCopies()
+    {
+        List<Employee> salesCopies = new()
+        {
+            new Employee {ID = 1, Name = "John Doe", Age = 28, Department = "Sales"},
+            new Employee {ID = 2, Name = "Emily Sanders", Age = 29, Department = "Sales"},
+            new Employee {ID = 3, Name = "Benjamin Winters", Age = 30, Department = "Sales"},
+            new Employee {ID = 12, Name = "Mary Jane", Age = 35, Department = "Sales"}
+        };
+
+        return employees.Except(salesCopies).ToList();
+    }
+
     public List<string> GetEmployeesNotInITIgnoreCase()
     {
         var employeesNotInIT = employees.Select(e => e.Name)
@@ -47,4 +68,26 @@ public List<Employee> GetEmployeesNotInSalesUsingComparer()
 
         return employees.Except(employeesInSales, comparer).ToList();
     }
-}
+
+    public List<EmployeeRecord> GetEmployeeRecordsNotInSales()
+    {
+        List<EmployeeRecord> staff = new()
+        {
+            new EmployeeRecord(1, "John Doe", 28, "Sales"),
+            new EmployeeRecord(4, "Sheila Foxx", 31, "Marketing"),
+            new EmployeeRecord(6, "Grace Jones", 32, "IT")
+        };
+
+        List<EmployeeRecord> sales = new()
+        {
+            new EmployeeRecord(1, "John Doe", 28, "Sales")
+        };
+
+        return staff.Except(sales).ToList();
+    }
+
+    public List<Employee> GetEmployeesNotInITByID()
+    {
+        return employees.ExceptBy(employeesIT.Select(e => e.ID), e => e.ID).ToList();
+    }
+}

csharp-linq/UsingExceptInCSharp/UsingExceptInCSharp/Program.cs

@@ -1,2 +1,11 @@
-// See https://aka.ms/new-console-template for more information
-Console.WriteLine("Hello, World!");
+using UsingExceptInCSharp;
+
+var examples = new ExceptMethodExamples();
+
+Console.WriteLine(string.Join(", ", examples.GetDistinctDifference()));
+Console.WriteLine(examples.GetEmployeesNotInSales().Count);
+Console.WriteLine(examples.GetEmployeesNotInSalesFromCopies().Count);
+Console.WriteLine(examples.GetEmployeesNotInSalesUsingComparer().Count);
+Console.WriteLine(string.Join(", ", examples.GetEmployeeRecordsNotInSales().Select(e => e.Name)));
+Console.WriteLine(string.Join(", ", examples.GetEmployeesNotInITIgnoreCase()));
+Console.WriteLine(string.Join(", ", examples.GetEmployeesNotInITByID().Select(e => e.Name)));

csharp-linq/UsingExceptInCSharp/UsingExceptInCSharp/UsingExceptInCSharp.csproj

@@ -2,7 +2,7 @@
 
   <PropertyGroup>
     <OutputType>Exe</OutputType>
-    <TargetFramework>net8.0</TargetFramework>
+    <TargetFramework>net10.0</TargetFramework>
     <ImplicitUsings>enable</ImplicitUsings>
     <Nullable>enable</Nullable>
   </PropertyGroup>

csharp-linq/UsingExceptInCSharp/UsingExceptInCSharpTests/UsingExceptInCSharpTests.csproj

@@ -1,7 +1,7 @@
 <Project Sdk="Microsoft.NET.Sdk">
 
   <PropertyGroup>
-    <TargetFramework>net8.0</TargetFramework>
+    <TargetFramework>net10.0</TargetFramework>
     <ImplicitUsings>enable</ImplicitUsings>
     <Nullable>enable</Nullable>
 
@@ -10,10 +10,10 @@
   </PropertyGroup>
 
   <ItemGroup>
-    <PackageReference Include="coverlet.collector" Version="6.0.0" />
-    <PackageReference Include="Microsoft.NET.Test.Sdk" Version="17.8.0" />
-    <PackageReference Include="MSTest.TestAdapter" Version="3.1.1" />
-    <PackageReference Include="MSTest.TestFramework" Version="3.1.1" />
+    <PackageReference Include="coverlet.collector" Version="10.1.0" />
+    <PackageReference Include="Microsoft.NET.Test.Sdk" Version="18.11.0" />
+    <PackageReference Include="MSTest.TestAdapter" Version="4.5.2" />
+    <PackageReference Include="MSTest.TestFramework" Version="4.5.2" />
   </ItemGroup>
 
   <ItemGroup>

csharp-linq/UsingExceptInCSharp/UsingExceptInCSharpTests/UsingExceptUnitTests.cs

@@ -16,29 +16,46 @@ public void GivenAllEmployees_WhenExceptInvoked_ThenVerifyThatNoSalesEmployeesRe
         var sheilaRecord = nonSales.Find(i => i.Name == "Sheila Foxx");
 
         Assert.IsInstanceOfType(nonSales, typeof(List<Employee>));
+        Assert.HasCount(8, nonSales);
         Assert.IsNull(maryRecord);
         Assert.IsNotNull(sheilaRecord);
     }
 
+    [TestMethod]
+    public void GivenDuplicatesInFirstSequence_WhenExceptInvoked_ThenVerifyThatResultIsDistinct()
+    {
+        var result = _examples.GetDistinctDifference();
+
+        CollectionAssert.AreEqual(new List<int> { 1, 2, 4 }, result);
+    }
+
+    [TestMethod]
+    public void GivenCopiesOfSalesEmployees_WhenExceptInvokedWithoutComparer_ThenVerifyThatNothingIsRemoved()
+    {
+        var result = _examples.GetEmployeesNotInSalesFromCopies();
+
+        Assert.HasCount(12, result);
+    }
+
     [TestMethod]
     public void GivenAllEmployees_WhenExceptInvokedIgnoreCase_ThenVerifyThatNoITEmployeesReturned()
     {
         var nonIT = _examples.GetEmployeesNotInITIgnoreCase();
 
         Assert.IsNotNull(nonIT);
         Assert.IsInstanceOfType(nonIT, typeof(List<string>));
-        Assert.IsFalse(nonIT.Contains("ava knowles"));
-        Assert.IsFalse(nonIT.Contains("grace jones"));
+        Assert.HasCount(10, nonIT);
+        Assert.DoesNotContain("Ava Knowles", nonIT);
+        Assert.DoesNotContain("Grace Jones", nonIT);
     }
 
     [TestMethod]
-    [ExpectedException(typeof(ArgumentNullException))]
     public void GivenAllEmployees_WhenExceptInvokedAgainstNull_ThenVerifyThatExceptionThrown()
     {
         var numbers = new List<int> { 1, 2, 3, 4 };
-        List<int> emptyList = null;
+        List<int>? nullList = null;
 
-        var result = numbers.Except(emptyList);
+        Assert.ThrowsExactly<ArgumentNullException>(() => numbers.Except(nullList!));
     }
 
     [TestMethod]
@@ -50,7 +67,26 @@ public void GivenAllEmployees_WhenExceptInvoked_ThenVerifyThatNoSalesEmployeesRe
         var comparison = _employeeComparer.Equals(expectedRecord, sheilaRecord);
 
         Assert.IsInstanceOfType(nonSales, typeof(List<Employee>));
+        Assert.HasCount(8, nonSales);
         Assert.IsTrue(comparison);
         Assert.IsNotNull(sheilaRecord);
     }
-}
+
+    [TestMethod]
+    public void GivenRecords_WhenExceptInvokedWithoutComparer_ThenVerifyThatValueEqualityIsUsed()
+    {
+        var result = _examples.GetEmployeeRecordsNotInSales();
+
+        CollectionAssert.AreEqual(new List<string> { "Sheila Foxx", "Grace Jones" }, result.Select(e => e.Name).ToList());
+    }
+
+    [TestMethod]
+    public void GivenITEmployeeIDs_WhenExceptByInvoked_ThenVerifyThatNoITEmployeesReturned()
+    {
+        var result = _examples.GetEmployeesNotInITByID();
+
+        Assert.HasCount(10, result);
+        Assert.IsNull(result.Find(e => e.ID == 6));
+        Assert.IsNull(result.Find(e => e.ID == 7));
+    }
+}