Table of Contents
C# Unit Testing Objects, IEnumerables, and Dates
In a previous post we looked at an introduction to Unit Testing, I want to expand on that and start looking at different data types. To do this I added some additional content to the UserService class.
namespace UnitTesting{ public class UserService { public User GetUserById(int userId) { return new User { Id = userId, Name = "John Doe", CreationDate = new DateOnly(2024,6,14) }; } public DateOnly GetCreationDate(int userId) { return new DateOnly(2024,6,14); } public IEnumerable<User> GetUsers() { return new [] { new User { Id = 1, Name = "John Doe", CreationDate = new DateOnly(2024,6,28) }, new User { Id = 2, Name = "Jane Doe", CreationDate = new DateOnly(1998,5,14) }, new User { Id = 3, Name = "John Smith", CreationDate = new DateOnly(1978,8,5) } }; } } public class User { public int Id { get; set; } = 0; public string Name { get; set; } = string.Empty; public DateOnly? CreationDate { get; set; } = null; }}Date
Using Fluent Assertions gives us a large number of Test, a complete list can be found here. I have used some of these to test the Creation Date method within the User Service.
[Fact]public void UserService_GetCreationDate_ReturnDate(){ // Arrange var userService = new UserService(); int userId = 1; // Act var result = userService.GetCreationDate(userId); // Assert result.Should().NotBe(default); result.Should().Be(new DateOnly(2024,6,14)); result.Should().BeAfter(new DateOnly(2024, 6, 13)); result.Year.Should().Be(2024); result.Month.Should().Be(6); result.Day.Should().Be(14); result.DayOfWeek.Should().Be(DayOfWeek.Friday); result.DayOfYear.Should().Be(166); } Object
This time were going to test an Object, to do so I’m going to re-use the GetUserById method again. However we need to clean something up first, in each Test Case we New’d up the userService. To keep this cleaner we will create a private member and move the new to the constructor, and then update the already created tests to use the private member.
public class UserServiceTest{ private UserService _userService; public UserServiceTest() { _userService = new UserService(); }Now we can test the Object, here we have two test;
- BeofType<TypeName> – Validates that the correct type is returned.
- BeEquivalentTo – Does a Parity Check between two objects, this validates that all the property values are identical.
[Fact]public void UserService_GetUserById_ReturnNewUser(){ // Arrange int userId = 1; // Act var result = _userService.GetUserById(userId); // Assert result.Should().BeOfType<User>(); result.Should().BeEquivalentTo(new User { Id = userId, Name = "John Doe", CreationDate = new DateOnly(2024,6,14) });}IEnumerable
With an IEnumerable we can again check the Type, but we also have content checks to ensure that the contents of the IEnumerable are correct.
[Fact]public void UserService_GetAllUsers_ReturnAllUsers(){ // Arrange // Act var result = _userService.GetAllUsers(); // Assert result.Should().BeOfType<User[]>(); result.Should().ContainEquivalentOf(new User { Id = 1, Name = "John Doe", CreationDate = new DateOnly(2024, 6, 28) }); result.Should().Contain(x=> x.Id == 2 && x.Name == "Jane Doe");}