How to instantiate variable like WebDriverWait when test are given driver type as test case?

Question

I am doing UI tests. At first I started with Firefox Browser driver only so I would declare the WebDriverWait variable under the class and would assign it under the [SetUp] method as shown in the code block and every test would be able to use it.

public class FirefoxTest {
public IWebDriver _driver;
public WebDriverWait _wait;
    [SetUp]
    public void SetupTest() {
          _driver = new FirefoxDriver();
          _wait = new WebDriverWait(_driver, TimeSpan.FromSeconds(30));
    }

Then I tried to incorporate more BrowserDrivers by specifying them with the [TestCaseSource(typeof(WebDriverFactory), "Drivers")] attribute. So now the _driver variable have to be moved out of the [SetUp] and _wait variable doesn't know what _driver to use.

I tried to instantiate it in every Test but that was repetitive and those test used methods that also require WebDriverWait variable and those methods would not run a second time when another test tries to implement them because the WebDriverWait variable would already be declared.

My question is where can I instantiate WebDriverWait and other things that are driver dependent and that are usually written in [SetUp] and [TearDown] such as driver.Quit() when the driver are given as [TestCase].

Right now I have test written like

[TestCaseSource(typeof(WebDriverFactory), "Drivers")]
public void SomeTest(IWebDriver driver){
    driver.Navigate().GoTo....
}

The problem is that I then have to include

WebDriverWait _wait = new WebDriverWait(driver, TimeSpan.FromSeconds(30));
driver.Quit()

in all the tests and the _wait in all the methods that are reused in the tests. Things that I had in the [SetUp] and [Teardown].

JimEvans JimEvans · Accepted Answer · 2013-04-13T16:23:50

You have two choices here. You don't mention if the Drivers property on WebDriverFactory is a static or an instance property. If it's a static property, I'd add a static QuitAll method that I could call in my TearDown method. If it's an instance method, things get trickier, and I'm not sure you can get there from here with NUnit.

On the other hand, instead of creating a WebDriverFactory class to instantiate the drivers, there's another form of the TestCaseSource attribute that allows you to specify a property or field of the class your tests live in. It probably would also work for properties or fields of a base class, but you'd have to try that out to make sure. Then, you could use members of the same class your tests run from, and would have complete control over the driver objects' lifetimes. That would look something like this:

// WARNING! Untested code written from memory
// without the aid of an IDE. Not guaranteed to
// work or even compile without modification.
// Use private field, public property
// (personal choice). 
private List<IWebDriver> activeDrivers = new List<IWebDriver>();
public List<IWebDriver> ActiveDrivers
{
    get { return this.activeDrivers; }
}

[TestFixtureSetUp]
public void InitializeDrivers()
{
    // Will run once for the class.
    // Use [SetUp] attribute to run
    // before each test method.
    this.activeDrivers.Add(new InternetExplorerDriver());
    this.activeDrivers.Add(new FirefoxDriver());
    this.activeDrivers.Add(new ChromeDriver());
}

[TestFixtureTearDown]
public void QuitAllDrivers()
{
    foreach(IWebDriver driver in this.activeDrivers)
    {
        driver.Quit();
    }
}

[TestCaseSource("ActiveDrivers")]
public void MyTest(IWebDriver driver)
{
    // Test goes here
}

Notice I've not said anything about your WebDriverWait field. This is because the WebDriverWait object is pretty lightweight, and doesn't cost much to construct. If you think having the constructor on-demand looks ugly or too verbose in your code, you can factor that out into a separate method you can call from your tests, like so:

private void WaitUntil<T>(IWebDriver driver, Func<IWebDriver, T> until)
{
    WebDriverWait wait = new WebDriverWait(driver, TimeSpan.FromSeconds(30));
    wait.Until<T>(until);
}

How to instantiate variable like WebDriverWait when test are given driver type as test case?

2 Answers