Using ASP.NET Core's ConfigurationBuilder in a Test Project

Question

I want to use the IHostingEnvironment and ConfigurationBuilder in my functional test project, so that depending on the environment the functional tests

Answer 1

I added an appsettings.Development.json to the root of my test project. Then I added the appsettings file via the .ConfigureAppConfiguration() method. It will then call the main application's Startup() method but use the configuration settings in appsettings.Development.json.

    string Environment = "Development";

    var server = new TestServer(new WebHostBuilder()                
        .UseEnvironment(Environment)
        .ConfigureAppConfiguration(x => {
            x.SetBasePath(Directory.GetCurrentDirectory());
            x.AddJsonFile($"appsettings.{Environment}.json", optional: false, reloadOnChange: true);
            x.AddEnvironmentVariables();
            })
        .UseStartup()                
        );

    httpClient = server.CreateClient();

The httpClient can then be used to e.g. make web requests such as:

var response = await httpClient.GetAsync(url);
var responseString = await response.Content.ReadAsStringAsync();