Improving ASP.NET Core End-to-End Tests with Selenium Docker Images, see https://blog.dangl.me/archive/improving-aspnet-core-end-to-end-tests-with-selenium-docker-images/

docker-compose.yml

version: '3.4'

services:
  dangl.identity:
    image: danglidentity:dev
    environment:
      - ASPNETCORE_ENVIRONMENT=Production
      - ASPNETCORE_URLS=http://+:80
      - IdentityServerSettings:UseDevelopmentSigningCredentials=true
      - IdentityServerSettings:Authorities:0=localhost
      - DanglIconsSettings:DanglIconsApiBaseUrl=http://dangl.icons
      - DanglIconsSettings:DanglIconsFrontendBaseUrl=http://localhost:44849
      - DanglIconsSettings:DanglIconsApiKey=DockerE2ETestsApiKey
      - InitialAdminUserEmails:0=info@dangl-it.com
      - InitialAdminPassword=DockerE2EAdminPassword
      - AllowUnsecureJwtAuthorities=true
      - ConnectionStrings:DefaultConnection=Data Source=sql.data;Initial Catalog=Dangl.Identity;Integrated Security=False;User ID=SA;Password=DockerSqlPass123
    depends_on:
      - dangl.icons
      - sql.data
    ports:
      - "44848:80"
  dangl.icons:
    image: dangl.azurecr.io/danglicons:latest
    environment:
      - ASPNETCORE_ENVIRONMENT=Production
      - ASPNETCORE_URLS=http://+:80
      - IconAppConfiguration:AppFilesRootPath=/icons/
      - IconAppConfiguration:EnforceHttps=false
      - IconAppConfiguration:ApiKeys:0=DockerE2ETestsApiKey
    ports:
      - "44849:80"
    expose:
      - "80"
  sql.data:
    image: mcr.microsoft.com/mssql/server:2017-latest
    environment:
      - ACCEPT_EULA=Y
      - SA_PASSWORD=DockerSqlPass123
    ports:
      - "5434:1433"
  selenium.standalone:
    image: selenium/standalone-chrome:3.141.59
    ports:
      - "4444:4444"
    shm_size: '2gb'

E2eTestsBase.cs

using OpenQA.Selenium;
using OpenQA.Selenium.Chrome;
using OpenQA.Selenium.Remote;
using System;
using System.Diagnostics;
using System.IO;
using System.Reflection;
using System.Threading.Tasks;
using Xunit;

namespace Dangl.Identity.E2E.Tests
{
    [Collection(nameof(E2eTestsCollection))]
    public class E2eTestsBase : IDisposable
    {
        protected readonly E2eTestsFixture _e2ETestsFixture;
        protected readonly RemoteWebDriver _seleniumDriver;
        protected readonly string _username;
        protected readonly string _email;
        protected readonly string _password = "DeveloperTestPassword";

        public E2eTestsBase(E2eTestsFixture e2ETestsFixture)
        {
            _username = Guid.NewGuid().ToString();
            _email = $"{_username}@example.com";
            _e2ETestsFixture = e2ETestsFixture;
            _seleniumDriver = GetAndInitializeWebDriver();
        }

        private RemoteWebDriver GetAndInitializeWebDriver()
        {
            if (E2eTestsSettings.UsesSeleniumInDocker)
            {
                // Use a RemoteWebDriver to connect to Chrome in the Selenium Standalone Docker container
                var chromeOptions = GetChromeOptions();
                return new RemoteWebDriver(new Uri(E2eTestsSettings.DockerRemoteWebDriverUrl), chromeOptions);
            }
            else
            {
                // Using a regular ChromeDriver to connect to a local Chrome instance
                var assemblyLocation = Path.GetDirectoryName(Assembly.GetExecutingAssembly().Location);
                var chromeOptions = GetChromeOptions();
                return new ChromeDriver(assemblyLocation, chromeOptions);
            }
        }

        private ChromeOptions GetChromeOptions()
        {
            var chromeOptions = new ChromeOptions();
            chromeOptions.AddArgument("--lang=en");
            if (!Debugger.IsAttached)
            {
                chromeOptions.AddArgument("--headless");
                chromeOptions.AddArgument("--window-size=1920,1080");
            }

            return chromeOptions;
        }

        public void Dispose()
        {
            _seleniumDriver.Dispose();
        }
    }
}

SignupAsync.cs

protected async Task SignupAsync()
{
    _seleniumDriver.Url = E2eTestsSettings.BrowserDanglIdentityBaseUrl;
    var registerButton = _seleniumDriver.FindElement(By.XPath("//a[.='Register']"));
    await registerButton.ClickAndWaitAsync();

    var usernameFormField = _seleniumDriver.FindElement(By.XPath("//input[@name='username']"));
    var emailFormField = _seleniumDriver.FindElement(By.XPath("//input[@name='email']"));
    var passwordFormField = _seleniumDriver.FindElement(By.XPath("//input[@name='password']"));

    usernameFormField.SendKeys(_username);
    emailFormField.SendKeys(_email);
    passwordFormField.SendKeys(_password);

    var acceptTosCheckbox = _seleniumDriver.FindElement(By.ClassName("mat-checkbox-inner-container"));
    acceptTosCheckbox.Click();

    var confirmRegisterButton = _seleniumDriver.FindElement(By.XPath("//button[.='Register' and not(@routerlink)]"));
    await confirmRegisterButton.ClickAndWaitAsync();
}