This project is a demonstration on how to do Web Api testing using Test Server. Instead of doing traditional unit tests where you write tests for each layer of your application. You can use Test Server and achieve a high level of code coverage but at the same time writing less code with lower maintenance.
var server = new TestServer(new WebHostBuilder()
.UseEnvironment("Development")
.UseStartup<Startup>()
.ConfigureTestServices((services) =>
{
//Setup injection
SetupBoundaryModules(services);
}));
HttpClient = server.CreateClient();
TestServer has a constructor which takes WebHostBuilder as one of it's arguments. WebHostBuilder is where we configure everything required so your test can reach your controller endpoints and be able to resolve any dependency.
.UseStartup<Startup>()
We're going to use the configuration of your Web Api so we don't have to worry about any IoC or any other configuration.
/// <summary>
/// This is where we setup our mocks
/// Typically they will be databases or other external services
/// where the process goes out of memory.
/// </summary>
/// <param name="serviceCollection"></param>
private void SetupBoundaryModules(IServiceCollection serviceCollection)
{
serviceCollection.AddTransient(o => ExternalApiService.Object);
}
Here is where we setup any mock that we will need in our tests. The philosophy of this type of testing is that we mock out any dependency that will go out of process. In other words any external database or service that isn't part of our codebase. We refer to this as Boundary Modules as anything not in memory of our application is where our boundary is.
public class PersonControllerTests : TestSetup
{
[Fact]
public async Task CanGet()
{
// Arrange
const int personId = 1234;
var testPerson = new Domain.Models.Person {PersonId = personId, FirstName = "Nick", Surname = "Gowdy"};
ExternalApiService.Setup(x => x.GetAsync(It.IsAny<int>()))
.ReturnsAsync(testPerson);
// Act
var response = await HttpClient.GetAsync($"person/{personId}");
// Assert
var responseString = await response.Content.ReadAsStringAsync();
var person = JsonConvert.DeserializeObject<Person>(responseString);
Assert.NotNull(person);
Assert.Equal(personId, person.PersonId);
Assert.Equal("Nick", person.FirstName);
Assert.Equal("Gowdy", person.Surname);
}
}
In this test we use HttpClient as defined in the setup and as we're using Test Server we only need to call the endpoint (We don't have to worry about the base address).