AMA: adopting a TDD/BDD approach

João Monteiro asks…

I recently joined a small company where I am the only QA and the test automation suite was already written in a given/when/then style but rarely (if not at all) gets read by the rest of the team (product or developers). Any tips on how to mentor the team to adopt a BDD approach? Do you recommend any tools / framework to share the features in a centralised place easily accessible by the rest of the team an not just on the tests repository?

Continue reading “AMA: adopting a TDD/BDD approach”

AMA: C# WebDriver Questions

omayer asks…

how to use test data from xlsx in c# webdriver, thank you in advance.

My response…

I haven’t done this as I’ve managed data/scenarios using SpecFlow, but there’s this post that should help you.

omayer also asks…

Handling popup Windows in C# WebDriver – Closing the popup window , finding elements on popup window, locating element inside popup window and frameset

My response…

Stackoverflow is a good resource for these types of questions; there’s some examples on how to do this here.

pallavi asks…

Which tool can we use for report generation in selenium with C#

My response…

This very much depends on which framework you are using to manage your tests. I have used SpecFlow which allows a formatted HTML report of test results.

pallavi also asks…

Can we use selenium with coded ui in visual studio? If I use with coded ui then what template it will follow

My response…

My experience with CodedUI tests in C# has only been negative. When I looked at it, the approach Microsoft used was to generate a huge number of lines of CodedUI test code which I couldn’t understand or make into reusable objects. I much prefer Selenium/WebDriver for any web based tests, and to use White to test any non-web based UIs. I am not familiar with CodedUI templates since it has been a long time since I looked at it.

 

Five automated acceptance test anti-patterns

Whilst being involved with lots of people writing automated acceptance tests using tools like SpecFlow and WebDriver I’ve seen some ‘anti-patterns’ emerge that can make these tests non-deterministic (flaky), very fragile to change and less efficient to run.

Here’s five ‘anti-patterns’ I’ve seen and what you can do instead.

Anti-pattern One: Not using page-objects

Page objects are just a design pattern to ensure automated UI tests use reusable, modular code. Not using them, eg, writing WebDriver code directly in step definitions, means any changes to your UI will require updates in lots of different places instead of the one ‘page’ class.

Bad

[When(@"I buy some '(.*)' tea")]
public void WhenIBuySomeTea(string typeOfTea)
{
Driver.FindElement(By.Id("tea-"+typeOfTea)).Click();
Driver.FindElement(By.Id("buy")).Click();
}

Better

[When(@"I buy some '(.*)' tea")]
public void WhenIBuySomeTea(string typeOfTea)
{
     MenuPage.BuyTea(typeOfTea);
}

Complicated set up scenarios within the tests themselves

Whilst there’s a place for automated end-to-end scenarios (I call these user journies), I prefer most acceptance tests to jump straight to the point.

Bad

Scenario: Accept Visa and Mastercard for Australia
 Given I am on the home page for Australia
 And I choose the tea menu
 And I select some 'green tea'
 And I add the tea to my basket
 And I choose to checkout
 Then I should see 'visa' is accepted
 And I should see 'mastercard' is accepted

Better

This usually requires adding some special functionality to your app, but the ability for testing to ‘jump’ to certain pages with data automatically set up makes automated tests much easier to read and maintain.

Scenario: Accept Visa and Mastercard for Australia
 Given I am the checkout page for Australia
 Then I should see 'visa' is accepted
 And I should see 'mastercard' is accepted

Using complicated x-path or CSS selectors

Using element identification selectors that have long chains from the DOM in them leads to fragile tests, as any change to that chain in the DOM will break your tests.

Bad

private static readonly By TeaTypeSelector =
            By.CssSelector(
                "#input-tea-type > div > div.TeaSearchRow > div.TeaSearchCell.no > div:nth-child(2) > label");

Better

Identify by ‘id’ (unique) or ‘class’. If there’s multiple elements in a group, create a parent container and iterate through them.

private static readonly By TeaTypeSelector = By.Id("teaType");

Directly executing JavaScript

Since WebDriver can directly execute any arbitrary JavaScript, it can be tempting to bypass DOM manipulation and just run the JavaScript.

Bad

public void RemoveTea(string teaType)
{
  (driver as IJavaScriptExecutor).ExecuteScript(string.Format("viewModel.tea.types.removeTeaType(\"{0}\");", teaType));
  }

Better

It is much better to let the WebDriver control the browser elements which should fire the correct JavaScript events and call the JavaScript, as that way you avoid having your ‘test’ JavaScript in sync to your ‘real’ JavaScript.

public void RemoveTea(string teaType)
{
  driver.FindElement(By.Id("remove-"+teaType)).Click();
}

Embedding implementation detail in your features/scenarios

Acceptance test scenarios are meant to convey intention over implementation. If you start seeing things like URLs in your test scenarios you’re focusing on implementation.

Bad


 Scenario: Social media links displayed on checkout page
   Given I am the checkout page for Australia
   Then I should see a link to 'http://twitter.com/beautifultea'
   And I should see a link to 'https://facebook.com/beautifultea'
 

Better

Hide implementation detail in the steps (or pages, or config) and make your scenarios about the test intention.


 Scenario: Social media links displayed on checkout page
   Given I am the checkout page for Australia
   Then I should see a link to the Beautiful Tea Twitter account
   And I should see a link to the Beautiful Tea Facebook page
 

I hope you’ve enjoyed these anti-patterns. Leave a comment below if you have any of your own.

You probably don’t need a specification framework

I think plain language specification frameworks like SpecFlow and Cucumber are great, but have a lot of overhead and are way overused.

If you don’t have non-technical folk collaborating with you on your specifications, try writing plain automated tests instead. This means using plain NUnit/MSTest over SpecFlow in C# or minitest over Cucumber in Ruby. You’ll avoid the overhead of maintaining a plain language specification framework and be able to focus on developing a great set of tests instead.

It’s easier than you think to add a plain language specification layer to a set of well structured plain tests. So only add the specification layer when you need it, because chances are you ain’t gonna.

Avoid using case statements in your cucumber/specflow/jbehave step definitions

I quite frequently come across a scenario that looks something like this:

Scenario: Create some animals
  Given I am a zoo keeper
  When I create a giraffe
  And I create a lion
  And I create a pony
  And I create a unicorn
  Then I should have a zoo

and step definitions that implement the When steps with a single step definition:

When /^I create a (\D+)$/ do |animal|
  case animal
    when 'lion'
      create_a_lion()
    when 'giraffe'
      create_a_giraffe()
    when 'pony'
      create_a_pony()
    else
      raise 'Unknown animal'
  end
end

I don’t like having case statements in steps for a number of reasons:

  • For readability and maintainability reasons I try to keep my step definitions as short as possible (usually a couple of lines), and using a case statement violates this principle;
  • Raising an exception to catch invalid usage of the step (in an else clause) replicates what these BDD frameworks already do, provide feedback about unimplemented steps;
  • IDEs that support step auto completion (such as RubyMine & Visual Studio) will not suggest valid steps as they don’t understand how you’ve implemented a case statement; and
  • If used inappropriately (such as our unicorn step), the test will only fail at run-time whereas most IDEs will highlight non-matching steps as you’re writing.

For example, you could change our steps to look something like this:

When /^I create a lion$/ do
  create_a_lion()
end

When /^I create a giraffe$/ do
  create_a_giraffe()
end

When /^I create a pony/ do
  create_a_pony()
end

Even though this is three times as many step definitions, it is actually less code (9 lines compared to 12).

By using this approach it is obvious we can’t currently create a unicorn as RubyMine tells us before we even run our tests. And we don’t need to raise any exceptions myself.

rubymine highlights unimplemented steps

Whilst a lot of people use case statements in steps to reduce the number of steps, it is actually counter intuitive as it means you have more code to do so, and the outcome is less usable when writing scenarios. So, please avoid putting case statements in your step definitions.