Unit test exception when calling API service using IHttpContextAccessor [duplicate] - api

Question

I have a method to get header value using IHttpContextAccessor
public class HeaderConfiguration : IHeaderConfiguration
{
public HeaderConfiguration()
{
}
public string GetTenantId(IHttpContextAccessor httpContextAccessor)
{
return httpContextAccessor.HttpContext.Request.Headers["Tenant-ID"].ToString();
}
}
I am testing GetBookByBookId method
Let's say the method looks like this:
public class Book
{
private readonly IHttpContextAccessor _httpContextAccessor;
private IHeaderConfiguration _headerConfiguration;
private string _tenantID;
public Book(IHeaderConfiguration headerConfiguration, IHttpContextAccessor httpContextAccessor){
var headerConfig = new HeaderConfiguration();
_httpContextAccessor = httpContextAccessor;
_tenantID = headerConfig.GetTenantId(_httpContextAccessor);
}
public Task<List<BookModel>> GetBookByBookId(string id){
//do something with the _tenantId
//...
}
}
Here's my unit test for GetBookByBookId method
[Fact]
public void test_GetBookByBookId()
{
//Arrange
//Mock IHttpContextAccessor
var mockHttpContextAccessor = new Mock<IHttpContextAccessor>();
mockHttpContextAccessor.Setup(req => req.HttpContext.Request.Headers["Tenant-ID"].ToString()).Returns(It.IsAny<string>());
//Mock HeaderConfiguration
var mockHeaderConfiguration = new Mock<IHeaderConfiguration>();
mockHeaderConfiguration.Setup(x => x.GetTenantId(mockHttpContextAccessor.Object)).Returns(It.IsAny<string>());
var book = new Book( mockHttpContextAccessor.Object, mockHeaderConfiguration.Object);
var bookId = "100";
//Act
var result = book.GetBookByBookId(bookId);
//Assert
result.Result.Should().NotBeNull().And.
BeOfType<List<BookModel>>();
}
But for this line:
mockHttpContextAccessor.Setup(req => req.HttpContext.Request.Headers["Tenant-ID"].ToString()).Returns(It.IsAny<string>());
It says
System.NotSupportedException: 'Type to mock must be an interface or an abstract or non-sealed class. '
I was wondering what's the proper way to mock IHttpContextAccessor with header value?

Answer 1

You can use the DefaultHttpContext as a backing for the IHttpContextAccessor.HttpContext. Saves you having to set-up too many things
Next you cannot use It.IsAny<string>() as a Returns result. They were meant to be used in the set up expressions alone.
Check the refactor
[Fact]
public async Task test_GetBookByBookId() {
//Arrange
//Mock IHttpContextAccessor
var mockHttpContextAccessor = new Mock<IHttpContextAccessor>();
var context = new DefaultHttpContext();
var fakeTenantId = "abcd";
context.Request.Headers["Tenant-ID"] = fakeTenantId;
mockHttpContextAccessor.Setup(_ => _.HttpContext).Returns(context);
//Mock HeaderConfiguration
var mockHeaderConfiguration = new Mock<IHeaderConfiguration>();
mockHeaderConfiguration
.Setup(_ => _.GetTenantId(It.IsAny<IHttpContextAccessor>()))
.Returns(fakeTenantId);
var book = new Book(mockHttpContextAccessor.Object, mockHeaderConfiguration.Object);
var bookId = "100";
//Act
var result = await book.GetBookByBookId(bookId);
//Assert
result.Should().NotBeNull().And.
BeOfType<List<BookModel>>();
}
There may also be an issue with the Class Under Test as it is manually initializing the HeaderConfiguration when it should actually be explicitly injected.
public Book(IHeaderConfiguration headerConfiguration, IHttpContextAccessor httpContextAccessor) {
_httpContextAccessor = httpContextAccessor;
_tenantID = headerConfiguration.GetTenantId(_httpContextAccessor);
}

Answer 2

In my scenario I had to mock IHttpContextAccessor and access the inner request url bits.
I'm sharing it here because I spent a decent amount of time figuring this out and hopefully it'll help someone.
readonly Mock<IHttpContextAccessor> _HttpContextAccessor =
new Mock<IHttpContextAccessor>(MockBehavior.Strict);
void SetupHttpContextAccessorWithUrl(string currentUrl)
{
var httpContext = new DefaultHttpContext();
setRequestUrl(httpContext.Request, currentUrl);
_HttpContextAccessor
.SetupGet(accessor => accessor.HttpContext)
.Returns(httpContext);
static void setRequestUrl(HttpRequest httpRequest, string url)
{
UriHelper
.FromAbsolute(url, out var scheme, out var host, out var path, out var query,
fragment: out var _);
httpRequest.Scheme = scheme;
httpRequest.Host = host;
httpRequest.Path = path;
httpRequest.QueryString = query;
}
}

Answer 3

If you are making use of the wonderful NSubstitute package for NUnit, you can do this...
var mockHttpAccessor = Substitute.For<IHttpContextAccessor>();
var context = new DefaultHttpContext
{
Connection =
{
Id = Guid.NewGuid().ToString()
}
};
mockHttpAccessor.HttpContext.Returns(context);
// usage...