Cannot get any test to run.

[TechyGuy99]

When i debug, it gets through all the API startup logic with no errors, then when it goes to execute the line in the test below, if fails.

when i tries to execute the test, it throws the error.
Why is it looking for WebApplication and failing? I tried adding to services collection, but that collection is read only.

System.InvalidOperationException : Could not resolve a service of type 'Microsoft.AspNetCore.Builder.WebApplication' for the parameter 'app' of method 'Configure' on type 'Vitech.Sidekick.DiagramAPI.Startup'.
---- System.InvalidOperationException : No service for type 'Microsoft.AspNetCore.Builder.WebApplication' has been registered.

Function Main of API i am testing:

Loads no issue.
namespace Vitech.Sidekick.DiagramAPI
{
public class Program
{
public static void Main(string[] args)
{
var builder = WebApplication.CreateBuilder(args);

        // Add services to the container.
        var configuration = builder.Configuration;

        var start = new Startup(builder);

        start.ConfigureServices(builder.Services);

        
        start.Configure(start.Application);
       

        start.Application.Run();
    }




}

}

1. Here is my test. does nothing.

   [Fact]
   public void TestMVC()
   {
   MyController.Instance(); // will get above exception once i get here.
   }

TestStartup.cs

namespace MyApp.Tests
{

using Microsoft.Extensions.DependencyInjection;
using Microsoft.AspNetCore.Hosting;
using Microsoft.Extensions.DependencyInjection.Extensions;
using Vitech.Sidekick.DiagramAPI;

using Microsoft.Extensions.Configuration;

using Moq;
using Vitech.Sidekick.DiagramAPI.Controllers;
using Vitech.Sidekick.DiagramData;
using Microsoft.AspNetCore.Builder;
using Microsoft.EntityFrameworkCore;
using MyTested.AspNetCore.Mvc;

public class TestStartup : Startup
{

    public TestStartup() : base(WebApplication.CreateBuilder())
    {

        Environment.SetEnvironmentVariable("ASPNETCORE_ENVIRONMENT", "Development");

    }

    public void ConfigureTestServices(IServiceCollection services)
    { 
        base.ConfigureServices(Builder.Services);
     


    }

    public override void Configure(WebApplication app)
    {
        
        base.Configure(app);

    }

    /// <summary>
    /// Create test db.
    /// </summary>
    /// <param name="builder"></param>
    protected override void AddDbContext(WebApplicationBuilder builder)
    {

        //var optionsBuilder = new DbContextOptionsBuilder<DiagramDbContext>();
        builder.Services.AddDbContext<DiagramDbContext>(o =>
        {
            var connectionString = builder.Configuration.GetConnectionString(nameof(DiagramDbContext));
            Console.WriteLine($"ConnectionString = {connectionString}");
            o.UseInMemoryDatabase("SideKickDb");

        });

    }
}

}

API Startup:

using AutoMapper;
using Microsoft.AspNetCore.Identity;
using Microsoft.EntityFrameworkCore;
using Microsoft.OpenApi.Models;
using System;
using System.Net;
using System.Text.Json.Serialization;
using Vitech.Sidekick.DiagramData;

namespace Vitech.Sidekick.DiagramAPI
{
///

/// Configures OWIN at startup.
///

public class Startup
{

    public Startup(): this(WebApplication.CreateBuilder())
    {

    }
    public Startup( WebApplicationBuilder builder)
    { 
            Configuration = builder.Configuration;
            Builder = builder;
    }

    protected WebApplicationBuilder Builder { get; set; }

    public WebApplication Application { get; set; }

    public IConfiguration Configuration { get; }

    public virtual void ConfigureServices(IServiceCollection services)
    {

// var services = builder.Services;
services.AddSingleton(Configuration);

        services.AddControllers();
        // Learn more about configuring Swagger/OpenAPI at https://aka.ms/aspnetcore/swashbuckle
        services.AddEndpointsApiExplorer();
        services.AddSwaggerGen();
        services.AddAuthorization();

        services.AddAuthentication();



        var section = Configuration.GetSection("ServiceSettings");
        ServiceSettings? settings = section.Get<ServiceSettings?>();

        if (settings != null)
        {
            services.AddSingleton(settings);
        }
     

        services.AddSwaggerGen(c =>
        {
            c.SwaggerDoc("v1", new OpenApiInfo
            {
                Version = "v1",
                Title = "DiagramAPI",
                Description = "DiagramAPI",


            });
            var securitySchema = new OpenApiSecurityScheme
            {
                Description = "JWT Authorization header using the Bearer scheme. Example: \"Authorization: Bearer {token}\"",
                Name = "Authorization",
                In = ParameterLocation.Header,
                Type = SecuritySchemeType.Http,
                Scheme = "bearer",
                Reference = new OpenApiReference
                {
                    Type = ReferenceType.SecurityScheme,
                    Id = "Bearer"
                }
            };
            c.AddSecurityDefinition("Bearer", securitySchema);

            var securityRequirement = new OpenApiSecurityRequirement();
            securityRequirement.Add(securitySchema, new[] { "Bearer" });
            c.AddSecurityRequirement(securityRequirement);
        });

        services.AddControllers().AddJsonOptions(options =>
       options.JsonSerializerOptions.Converters.Add(new JsonStringEnumConverter()));
      

        services.AddTransient<SessionDataProvider>();
        CreateDbContext(Builder);
        Application = Builder.Build();
        
       
    }

    private  void CreateDbContext(WebApplicationBuilder builder)
    {
        string environment = Environment.GetEnvironmentVariable("ASPNETCORE_ENVIRONMENT");
        

        var currentDir = Directory.GetCurrentDirectory();
       

        Console.WriteLine(currentDir);
        // Build config
        //string basePath = Path.Combine(currentDir, @"..\Vitech.Sidekick.DiagramAPI");

        // Console.WriteLine(basePath);

        builder.Configuration
       .SetBasePath(currentDir)
        .AddJsonFile("appsettings.json", optional: false, reloadOnChange: true)
        .AddJsonFile($"appsettings.{environment}.json", optional: true)
        .AddEnvironmentVariables();


        // Auto Mapper Configurations
        var mapperConfig = new MapperConfiguration(mc =>
        {
            mc.AddProfile(new Mapper());
        });

        IMapper mapper = mapperConfig.CreateMapper();
        builder.Services.AddSingleton(mapper);


        // Add Db
        AddDbContext(builder);


    }

    protected virtual void AddDbContext(WebApplicationBuilder builder)
    {

        //var optionsBuilder = new DbContextOptionsBuilder<DiagramDbContext>();
        builder.Services.AddDbContext<DiagramDbContext>(o =>
        {
            var connectionString = builder.Configuration.GetConnectionString(nameof(DiagramDbContext));
            Console.WriteLine($"ConnectionString = {connectionString}");
            o.UseSqlServer(connectionString);

        });
    }

    public virtual void Configure(WebApplication app)
    {

        // Configure the HTTP request pipeline.
        if (app.Environment.IsDevelopment())
        {
            app.UseSwagger();
            app.UseSwaggerUI(opts =>
            {

                opts.EnablePersistAuthorization();

            }).UseAuthentication();
        }


        app.UseHttpsRedirection();

        app.UseAuthorization();
        app.UseAuthentication();

        app.MapControllers();
        
        CreateDbIfNotExists(app);
    }


    private  void CreateDbIfNotExists(IHost host)
    {
        using (var scope = host.Services.CreateScope())
        {
            var services = scope.ServiceProvider;
            try
            {
                var context = services.GetRequiredService<DiagramDbContext>();
                DbInitializer.Initialize(context);
            }
            catch (Exception ex)
            {
                var logger = services.GetRequiredService<ILogger<Program>>();
                logger.LogError(ex, "An error occurred creating the DB.");
            }
        }
    }
}

}