How do I implement parallel execution on Specflow/Selenium/C#/NUnit?

Question

I have an existing project that runs tests sequentially, and I'm trying to implement parallel execution.

I initially added these attributes to AssemblyInfo.cs

[assembly: Parallelizable(ParallelScope.Fixtures)]
[assembly: LevelOfParallelism(2)]

In order to see that parallel execution was being attempted, I had to create two features, each with one test, then in Visual Studio's Test Explorer, run them all. This tried to run each test in each feature at the same time.

I have one of the tests set to run in Chrome, and the other in Firefox. This is also the order that the webdriver invokes the browser instances.

Chrome opens first, then Firefox opens - but Chrome is orphaned and the test gets conducted only in Firefox.

This I believe is because my webdriver is static, so Firefox is hijacking the thread used by Chrome. I've read that I cannot use a static webdriver for parallel testing, so I'm attempting to a non-static one.

It seems I now have to pass the driver between methods to ensure that all operations are conducted on that particular instance.

Having implemented the webdriver non-statically, I'm first trying to ensure that a single test runs, before trying to run all the tests in parallel.

But I've hit a road-block. In the following test, the driver is reset to null upon commencement of the second (When) step:

Scenario Outline: C214 Log in
    Given I launch the site for <profile> and <environment> and <parallelEnvironment>
    When I log in to the Normal account
    Then I see that I am logged in

        Examples:
        | profile | environment | parallelEnvironment |
        | single  | Chrome75    |                     |
        #| single  | Firefox67   |                     |

How do I make the non-static webdriver persist between steps?

Is ThreadLocal the answer? If so, will using it be a problem later down the line if I want to use this parallel execution in Selenium Grid over Windows Desktop, android and iOS devices?

Here's my set-up:

SetUp.cs

using TechTalk.SpecFlow;
using OpenQA.Selenium;
using OpenQA.Selenium.Chrome;
using OpenQA.Selenium.Edge;
using OpenQA.Selenium.Firefox;
using OpenQA.Selenium.IE;
using System;

namespace OurAutomation
{
    [Binding]
    public class SetUp
    {
        public IWebDriver Driver;
        public string theEnvironment;

        public IWebDriver InitialiseDriver(string profile, string environment, string parallelEnvironment)
        {
            theEnvironment = environment;

            if (profile == "single")
            {
                if (environment.Contains("IE"))
                {
                    Driver = new InternetExplorerDriver();
                }
                else if (environment.Contains("Edge"))
                {
                    Driver = new EdgeDriver();
                }
                else if (environment.Contains("Chrome"))
                {
                    Driver = new ChromeDriver(@"C:\Automation Test Drivers\");
                }
                else if (environment.Contains("Firefox"))
                {
                    Driver = new FirefoxDriver(@"C:\Automation Test Drivers\");
                }
            }

            Driver.Manage().Window.Maximize();

            Driver.Manage().Timeouts().ImplicitWait = TimeSpan.FromSeconds(5);

            return Driver;
        }

        [AfterScenario]
        public void AfterScenario()
        {
            Driver.Quit();
        }
    }
}

BaseSteps.cs

using OpenQA.Selenium;

namespace OurAutomation.Steps
{
    public class BaseSteps : SetUp
    {
        public IWebDriver driver;

        public void DriverSetup(string profile, string environment, string parallelEnvironment)
        {
            driver = InitialiseDriver(profile, environment, parallelEnvironment);
        }
    }
}

LaunchTestSteps.cs

using OurAutomation.BaseMethods;
using OurAutomation.Pages;
using TechTalk.SpecFlow;

namespace OurAutomation.Steps
{
    [Binding]
    public class LaunchTestSteps : BaseSteps
    {
        [Given(@"I launch the site for (.*) and (.*) and (.*)")]
        public void ILaunchTheSite(string profile, string environment, string parallelEnvironment)
        {
            DriverSetup(profile, environment, parallelEnvironment);
            new Common().LaunchSite(driver);
            new Core().Wait(10, "seconds");
        }
    }
}

There's more but not sure whether the full suite will be needed to figure this out. Perhaps it is obvious so far as to my fatal errors!

Answer 1

After much ado, found https://github.com/minhhoangvn/AutomationFramework which enabled me to strip out the necessary code to achieve parallel testing using ThreadLocal.