.Net Core Web Api CRUD Controller unit testing code sample

Unit testing in .Net Core has been made simple. It has been designed with testability in mind. TDD approach has paid rich dividends for the developers who follow them religiously. Unit tests gives you the confidence and faith in your code, catches errors early in the cycle and overall, improves productivity levels across the team. There is a upfront cost with unit testing but, it's worth the cost and effort. This code sample unit tests a typical CRUD web api controller. This code sample is compiled on .Net Core 2.0 and .Net Core Standard 2.0. We used xUnit as testing framework and test runner, Moq for mocking dependencies.

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using AutoMapper; using Moq; using VisualStudio99.Data.Repositories; using System; using System.Collections.Generic; using System.Linq; using System.Linq.Expressions; using System.Text; using System.Threading.Tasks; using Microsoft.AspNetCore.Mvc; using VisualStudio99.Api.Controllers; using Xunit; using VisualStudio99.Common.Dto; using VisualStudio99.Tests.Data; using VisualStudio99.Data; using VisualStudio99.Data.Mappers; namespace VisualStudio99.Tests { public class EmployeeControllerTests { private readonly Mock<IEmployeeRepository> mockRepo; private readonly Mock<EmployeeMapper> mockMapper; private readonly EmployeeController controller; public EmployeeControllerTests() { mockRepo = new Mock<IEmployeeRepository>(); mockMapper = new Mock<EmployeeMapper>(); controller = new EmployeeController(mockRepo.Object, mockMapper.Object); } [Fact] public async Task Post_ReturnsOkResult_WhenCreatingValidEmployee() { // Arrange & Act mockRepo.Setup(repo => repo.Add(It.IsAny<Employee>())).Verifiable(); mockRepo.Setup(repo => repo.SaveAsync()).ReturnsAsync(1); mockRepo.Setup(repo => repo.AnyAsync(It.IsAny<Expression<Func<Employee, bool>>>())).Returns(Task.FromResult(false)); // Act var result = await controller.Post(EmployeeData.GetNewEmployee()); //Assert mockRepo.Verify(repo => repo.Add(It.IsAny<Employee>()), Times.Once); mockRepo.Verify(repo => repo.SaveAsync(), Times.Once); var createdAtRouteResult = Assert.IsType<CreatedAtActionResult>(result); var employee = Assert.IsType<EmployeeDto>(createdAtRouteResult.Value); Assert.Equal("TestEmployee", employee.Name); } [Fact] public async Task Post_ReturnsBadRequest_WhenUpdatingInvalidNullEmployee() { // Act var result = await controller.Post(null); //Assert mockRepo.Verify(repo => repo.Add(It.IsAny<Employee>()), Times.Never); Assert.IsType<BadRequestObjectResult>(result); } [Fact] public async Task Post_ReturnsBadRequest_WhenAddingExistingEmployee() { mockRepo.Setup(repo => repo.AnyAsync(It.IsAny<Expression<Func<Employee, bool>>>())).Returns(Task.FromResult(true)); // Act var result = await controller.Post(EmployeeData.GetNewEmployee()); //Assert mockRepo.Verify(repo => repo.Add(It.IsAny<Employee>()), Times.Never); Assert.IsType<BadRequestObjectResult>(result); } [Fact] public async Task Get_Returns_All_Employees() { // Arrange mockRepo.Setup(repo => repo.GetAsync()).Returns(Task.FromResult(EmployeeData.GetEmployees())); // Act var result = await controller.GetAllAsync(); // Assert var okResult = Assert.IsType<OkObjectResult>(result); Assert.IsType<List<EmployeeDto>>(okResult.Value); mockRepo.Verify(repo => repo.GetAsync(), Times.AtMostOnce); } [Theory] [InlineData(1)] public async Task Get_ReturnsHttpOkResult_ForValidEmployeeId(int empId) { // Arrange string employeeName = "testEmployee"; mockRepo.Setup(repo => repo.GetAsync(It.IsAny<Expression<Func<Employee, bool>>>())).Returns(Task.FromResult(EmployeeData.GetEmployees().Where(t => t.EmpId == empId).ToList())); // Act var result = await controller.Get(empId); // Assert var okResult = Assert.IsType<OkObjectResult>(result); var emp = Assert.IsType<List<EmployeeDto>>(okResult.Value).FirstOrDefault(); mockRepo.Verify(repo => repo.GetAsync(It.IsAny<Expression<Func<Employee, bool>>>()), Times.Once); Assert.True(emp.EmpName == employeeName); } [Fact] public async Task Get_ReturnsBadRequestResult_ForInValidEmpId() { // Arrange var empId = -1; mockRepo.Setup(repo => repo.GetAsync(It.IsAny<Expression<Func<Employee, bool>>>())).Returns(Task.FromResult(EmployeeData.GetEmployees().Where(t => t.EmpId == empId).ToList())); // Act var result = await controller.Get(empId); // Assert Assert.IsType<BadRequestObjectResult>(result); mockRepo.Verify(repo => repo.GetAsync(), Times.Never); } [Fact] public async Task Put_ReturnsBadRequestResult_WhenUpdatingInvalidNullEmployee() { // Arrange & Act // Act var result = await controller.Put(null); //Assert mockRepo.Verify(repo => repo.Update(It.IsAny<Employee>()), Times.Never); Assert.IsType<BadRequestObjectResult>(result); } [Fact] public async Task Put_ReturnsNotFoundRequest_WhenUpdatingInvalidEmployee() { // Arrange & Act mockRepo.Setup(repo => repo.AnyAsync(It.IsAny<Expression<Func<Employee, bool>>>())).Returns(Task.FromResult(false)); // Act var result = await controller.Put(new EmployeeDto() { EmpId = 99 }); //Assert mockRepo.Verify(repo => repo.Update(It.IsAny<Employee>()), Times.Never); Assert.IsType<NotFoundResult>(result); } [Fact] public async Task Put_ReturnsOkResult_WhenUpdatingValidEmployee() { // Arrange & Act mockRepo.Setup(repo => repo.Update(It.IsAny<Employee>())).Verifiable(); mockRepo.Setup(repo => repo.SaveAsync()).ReturnsAsync(1); mockRepo.Setup(repo => repo.AnyAsync(It.IsAny<Expression<Func<Employee, bool>>>())).Returns(Task.FromResult(true)); // Act var result = await controller.Put(new EmployeeDto() { EmpId = 1 }); //Assert mockRepo.Verify(repo => repo.Update(It.IsAny<Employee>()), Times.Once); mockRepo.Verify(repo => repo.SaveAsync(), Times.Once); Assert.IsType<NoContentResult>(result); } [Fact] public async Task Delete_ReturnsHttpBadRequest_ForInvalidEmployee() { // Arrange int empId = 99; mockRepo.Setup(repo => repo.AnyAsync(It.IsAny<Expression<Func<Employee, bool>>>())).Returns(Task.FromResult(false)); // Act var result = await controller.Delete(empId); // Assert Assert.IsType<BadRequestResult>(result); } [Fact] public async Task Delete_ReturnsNoContentResult_ForValidEmployee() { // Arrange int empId = 99; mockRepo.Setup(repo => repo.AnyAsync(It.IsAny<Expression<Func<Employee, bool>>>())).Returns(Task.FromResult(true)); mockRepo.Setup(repo => repo.SaveAsync()).ReturnsAsync(1); // Act var result = await controller.Delete(empId); // Assert mockRepo.Verify(repo => repo.Delete(It.IsAny<int>()), Times.Once); mockRepo.Verify(repo => repo.SaveAsync(), Times.Once); Assert.IsType<NoContentResult>(result); } } }