TestServer w/ WebHostBuilder doesn't read appsettings.json on ASP.NET Core 2.0, but it worked on 1.1

[natemcmaster]

From @neooleg on August 30, 2017 19:59

STR

1. Use .NET 2.0
2. Follow official manual to create integration tests
3. Use the following code for test server

_server = new TestServer(new WebHostBuilder()
    .UseEnvironment("Development")
    .UseContentRoot(projectDir)
    .UseStartup<TestStartup>());

h3. AR

• appsettings.json doesn't read and TestStartup doesn't receive them.
• It looks like breaking changes (not found anything documented it) because the same code worked on ASP.NET Core 1.1

h3. ER
appsettings.json should be read and passed into Startup.

Copied from original issue: aspnet/KestrelHttpServer#2042

[Tratcher]

@neooleg WebHostBuilder and TestServer do not read appsettings.json in any scenarios. CreateDefaultBuilder is the only component that includes appsettins.json by default:
https://github.com/aspnet/MetaPackages/blob/dev/src/Microsoft.AspNetCore/WebHost.cs#L148

[neooleg]

@Tratcher I see, thanks!

What is idiomatic way to read appsettings.json in tests?

Except doing it explicit (which is might be good depending on case):

_server = new TestServer(new WebHostBuilder()
    .UseEnvironment("Development")
    .UseContentRoot(projectDir)
    .UseConfiguration(new ConfigurationBuilder()
        .SetBasePath(projectDir)
        .AddJsonFile("appsettings.json")
        .Build()
    )
    .UseStartup<TestStartup>());

[Tratcher]

It needs to be explicit in all apps and tests unless you call CreateDefaultBuilder.

[Tratcher]

Note there is a ConfigureAppConfgiuration method that is a little easier than UseConfiguration.

[neooleg]

Do you recommend to use CreateDefaultBuilder() in tests as well?

[Tratcher]

It depends on what you're testing. If you're trying to mimic a full application then it may make sense.

[neooleg]

Thanks a lot, @Tratcher!

P.S. The issue might be closed from my point of view.