Overview
This skill guides QA engineers and test architects in writing production-grade Reqnroll
BDD tests for web and mobile automation in C#. It covers three execution paths — Selenium 4
with manual driver management, Selenium 3 via the Reqnroll.Actions plugin, and Appium 2
for Android mobile — all targeting TestMu AI (LambdaTest) cloud infrastructure.
Reqnroll is the actively maintained open-source successor to SpecFlow. Existing SpecFlow projects can migrate by swapping the NuGet package and namespace — no step definition rewrites required.
Key Execution Pathways
Framework Selection: Distinguishes between Selenium 4 (manual DriverFactory),
Selenium 3 (Reqnroll.SpecFlowCompatibility.Actions.LambdaTest plugin with
IBrowserInteractions), and Appium 2 (Appium.WebDriver, AndroidDriver).
Cloud vs Local: Reads LT_USERNAME and LT_ACCESS_KEY environment variables;
routes to hub.lambdatest.com (web) or mobile-hub.lambdatest.com (mobile).
Reports pass/fail to LambdaTest via lambda-status JavaScript executor calls in
[AfterScenario].
Parallelism: Uses [assembly: Parallelizable(ParallelScope.Fixtures)] with
[assembly: LevelOfParallelism(N)] (NUnit). State is shared between step definition
classes via ScenarioContext (injected by Reqnroll's DI container), not static fields.
Core Technical Patterns
Feature Files (Gherkin)
Each .feature file maps to one test class. Scenarios are tagged (@tagName) for
selective filtering with dotnet test --filter "Category=tagName". Background steps
run before every scenario in the file; Scenario Outlines drive data-driven testing via
Examples tables.
Step Definitions
Classes are decorated with [Binding]. Constructor injection (via Reqnroll's built-in
DI) receives ScenarioContext or shared context objects. One [Binding] class per
concern keeps files small. Regex-based step patterns use (.*) or typed captures
((\d+)) — no attribute-level type converters needed for primitives.
Hooks
[BeforeScenario] initialises the driver (stored in ScenarioContext["driver"]) and
navigates to the base URL. [AfterScenario] reads _scenarioContext.TestError (web) or
TestContext.CurrentContext.Result.Outcome.Status (mobile) to emit
lambda-status=passed/failed before driver.Quit().
ScenarioContext Driver Sharing
Drivers are stored as _scenarioContext["driver"] = driver and retrieved with
scenarioContext["driver"] as IWebDriver. This is required for parallel execution —
static driver fields cause race conditions.
Explicit Waits
WebDriverWait with Until(d => d.FindElement(locator)) replaces ImplicitWait
for dynamic content. A WaitAndFind(By) helper method encapsulates the 10-second
default; a WaitAndClick(By, int timeout) variant handles clickability.
Cloud Integration (TestMu / LambdaTest)
Web (Selenium 4)
var ltOptions = new Dictionary<string, object>
{
{ "build", "Build Name" },
{ "project", "Project Name" },
{ "w3c", true },
{ "selenium_version", "4.38.0" },
{ "sessionName", scenarioName },
{ "platformName", "Windows 11" }
};
var options = new ChromeOptions();
options.BrowserVersion = "latest";
options.AddAdditionalOption("LT:Options", ltOptions);
var driver = new RemoteWebDriver(
new Uri($"https://{userName}:{accessKey}@hub.lambdatest.com/wd/hub"), options);
Mobile (Appium 2)
var ltOptions = new Dictionary<string, object>
{
{ "build", "Build Name" },
{ "project", "Project Name" },
{ "w3c", true },
{ "app", "proverbial-android" }, // lt:// URI or pre-uploaded alias
{ "platformName", "android" },
{ "deviceName", "Galaxy.*" },
{ "platformVersion", "14" },
{ "isRealMobile", true },
{ "autoAcceptAlerts", true },
{ "autoGrantPermissions", true },
{ "sessionName", scenarioName }
};
var appiumOptions = new AppiumOptions();
appiumOptions.AddAdditionalAppiumOption("LT:Options", ltOptions);
var driver = new AndroidDriver(
new Uri($"https://{userName}:{accessKey}@mobile-hub.lambdatest.com/wd/hub"),
appiumOptions);
Reporting Pass/Fail
// Web (AfterScenario)
if (_scenarioContext.TestError == null)
((IJavaScriptExecutor)driver).ExecuteScript("lambda-status=passed");
else
((IJavaScriptExecutor)driver).ExecuteScript("lambda-status=failed");
// Mobile (AfterScenario)
bool passed = TestContext.CurrentContext.Result.Outcome.Status == TestStatus.Passed;
((IJavaScriptExecutor)driver).ExecuteScript("lambda-status=" + (passed ? "passed" : "failed"));
Quality Checkpoints
- Feature files use descriptive scenario names that double as the LambdaTest session name
ScenarioContextused for driver sharing — never static fields in parallel runs[assembly: Parallelizable(ParallelScope.Fixtures)]declared once in any.csfileLT_USERNAMEandLT_ACCESS_KEYread from environment — never hardcodedlambda-status=passed/failedemitted in every[AfterScenario]for cloud runsWebDriverWaitused throughout — no unconditionalThread.Sleepexcept transient Appium delays- Appium locators use
MobileBy.Id(resource-id) orMobileBy.AccessibilityIdbefore XPath driver.Quit()always called in[AfterScenario]to free cloud device slotsdotnet test --logger "console;verbosity=detailed"surfaces per-scenario pass/fail
Reference Structure
The reference/ directory contains detailed playbook sections:
| File | Contents |
|---|---|
playbook.md | Full implementation guide: project setup, all three driver modes, parallel execution, CI/CD, debugging table, best practices checklist |
cloud-integration.md | LambdaTest capability reference, LT:Options fields, tunnel setup, build/session naming, test observability |
selenium-4-patterns.md | Selenium 4 patterns: DriverFactory, multi-browser, ChromeOptions/FirefoxOptions/EdgeOptions, screenshot on failure |
selenium-3-patterns.md | Selenium 3 patterns: Reqnroll.SpecFlowCompatibility.Actions.LambdaTest, IBrowserInteractions, reqnroll.actions.json config |
appium-patterns.md | Appium 2 patterns: AndroidDriver, AppiumOptions, gesture helpers, MobileBy locators, app lifecycle |