There is no registered service of type 'Microsoft.AspNetCore.Hosting.IWebHostEnvironment

[curtic00]

Hi. I have a simple .net 8 blazor server project, and I am using this code

@using Microsoft.AspNetCore.Hosting;
@using Microsoft.Extensions.Hosting;
@Inject IWebHostEnvironment Env
.....

 @if (Env.IsDevelopment()) { jobId = 10011; } 

Works fine

When I try to Use Bunit,

 [Fact] [Trait("Category", "Test_Home_Page")] public void Test_HomePage_Caption() { var hostEnvironment = Services.GetRequiredService<FakeWebAssemblyHostEnvironment>(); hostEnvironment.SetEnvironmentToDevelopment(); // Arrange var cut = RenderComponent<Simpson.Blazor.Pages.Index>(); // Assert 

....
}
{
see https://bunit.dev/docs/test-doubles/fake-webassemblyhostenvironment.html
which I'm guessing now is for the Blazor web assembly project.

)

get the following error
... There is no registered service of type 'Microsoft.AspNetCore.Hosting.IWebHostEnvironment'.

What am I doing wrong...

TIA, charlie

[linkdotnet]

Hey @curtic00

The DI-Container of bUnit is disconnected from the one in your Program.cs, so you have to provide an implementation for IWebHostEnvironment. Either via mocking or providing a fake:

Faking

So basically you can create your own implementation:

public void Test_HomePage_Caption() { Services.AddScoped<IWebHostEnvironment>(_ => new FakeWebHostEnvironment()); // ... } private sealed class FakeWebHostEnvironment : IWebHostEnvironment { public string EnvironmentName { get; set; } = "Development"; public string ApplicationName { get; set; } public string ContentRootPath { get; set; } public IFileProvider ContentRootFileProvider { get; set; } public string WebRootPath { get; set; } public IFileProvider WebRootFileProvider { get; set; } }

Mocking

Or use a mocking library like NSubstitute:

public void Test_HomePage_Caption() { var hostEnv = Substitute.For<IWebHostEnvironment>(); hostEnv.EnvironmentName.Returns("Development"); Services.AddScoped<IWebHostEnvironment>(_ => hostEnv); // ... }

[curtic00]

Hi Steven Faking works a treat. Thanks Charlie From: Steven Giesel ***@***.***> Sent: 25 April 2025 18:35 To: bUnit-dev/bUnit ***@***.***> Cc: curtic00 ***@***.***>; Mention ***@***.***> Subject: Re: [bUnit-dev/bUnit] There is no registered service of type 'Microsoft.AspNetCore.Hosting.IWebHostEnvironment (Discussion #1711) Hey @curtic00 <https://github.com/curtic00> The DI-Container of bUnit is disconnected from the one in your Program.cs, so you have to provide an implementation for IWebHostEnvironment. Either via mocking or providing a fake: Faking So basically you can create your own implementation: public void Test_HomePage_Caption() { Services.AddScoped<IWebHostEnvironment>(_ => new FakeWebHostEnvironment()); // ... } private sealed class FakeWebHostEnvironment : IWebHostEnvironment { public string EnvironmentName { get; set; } = "Development"; public string ApplicationName { get; set; } public string ContentRootPath { get; set; } public IFileProvider ContentRootFileProvider { get; set; } public string WebRootPath { get; set; } public IFileProvider WebRootFileProvider { get; set; } } Mocking Or use a mocking library like NSubstitute: public void Test_HomePage_Caption() { var hostEnv = Substitute.For<IWebHostEnvironment>(); hostEnv.EnvironmentName.Returns("Development"); Services.AddScoped<IWebHostEnvironment>(_ => hostEnv); // ... } — Reply to this email directly, view it on GitHub <#1711 (comment)> , or unsubscribe <https://github.com/notifications/unsubscribe-auth/AUSOJFWAFRNTPAR2O5NX6OD23JW4HAVCNFSM6AAAAAB334L6RSVHI2DSMVQWIX3LMV43URDJONRXK43TNFXW4Q3PNVWWK3TUHMYTEOJUHE4TANA> . You are receiving this because you were mentioned. <https://github.com/notifications/beacon/AUSOJFXM37R3TYWHHX2KQGT23JW4HA5CNFSM6AAAAAB334L6RSWGG33NNVSW45C7OR4XAZNRIRUXGY3VONZWS33OINXW23LFNZ2KUY3PNVWWK3TUL5UWJTQAYWMZA.gif> Message ID: ***@***.*** ***@***.***> >