On July 23, 2019, I gave a webinar entitled, “How Do We Write Good Gherkin as Part of BDD?” in collaboration with Paul Merrill and his company, Beaufort Fairmont. This webinar was the follow-up to a previous webinar, What Is BDD, and How Do We Practice It? It was an honor to partner with Paul again to go further into BDD practices. (If you want to learn more about BDD, check out Beaufort Fairmont’s two-day BDD training offering, as well as their blog and other webinars.)
To see my webinar recording, register here. Definitely watch the previous webinar first.
Just like last time, attendees asks several great questions that we simply could not answer live. I categorized all questions we received and answered them below. Please note that some questions might be rephrased or combined with others.
Questions about BDD
What is BDD?
Behavior-Driven Development! Read more here.
In a typical Agile development process, who should write feature files?
The Three Amigos! Product owners, developers, and testers should all come together to figure out behaviors. I recommend doing Example Mapping to formulate before writing Gherkin scenarios. The green example cards should be turned into feature files. The specific person who writes the feature files is up to team preference. It could be a collaborative effort, or it could be divided-and-conquered. Any one of the Three Amigos can do it.
How can we apply BDD to SAFe (Scaled Agile Framework) teams?
BDD practices like Three Amigos meetings, Example Mapping, Behavior Specification with Gherkin, and Behavior Implementation can become part of any process. All of these practices happen at the level of the development teams. Teams could even share Gherkin steps and test frameworks wherever sharing makes sense. Check out BDD 101: Behavior-Driven Agile.
What advice can you give to teams that use BDD tests frameworks solely as an automation tool and not part of a greater BDD process?
Do the best with what you’ve got. Try to show how other BDD practices can pragmatically improve your team’s development and delivery work. See also:
Questions about Gherkin Syntax
What is the difference between a scenario and a scenario outline?
A scenario is a procedure of Given-When-Then steps that covers one example for one behavior. If there are any parameters for steps, then a scenario has exactly one combination of possible inputs. A scenario outline is a Given-When-Then procedure that can have multiple examples of one behavior provided as a table of input combos. Each input row will run the same steps once, just with different parameter inputs. See BDD 101: Gherkin by Example to see examples.
What do you think about long tables in scenarios?
Long tables in Gherkin usually look terrible. They’re hard to read, and they create a wall of text. They may also include unnecessary variations. Stick to the Unique Example rule.
Are Given steps mandatory, or can scenarios start directly with When steps?
None of the step types are mandatory. It is valid to write a scenario that skips the Given and has only When-Then steps. It is also valid to write scenarios that are Given-Then or Given-When. In fact, it is syntactically valid to put steps in any order. However, I strongly recommend keeping Given-When-Then step order to properly frame behaviors.
Are quotation marks required for parameters?
No, quotation marks are not required for parameters, but they are a popular convention, and one that I recommend. Quotes make parameters easy to identify.
Questions about Gherkin Scenarios
How do we make sure each scenario focuses on an individual, independent behavior?
Do Example Mapping first as a team. Write scenarios together, or review them with others. Ask, “What makes this behavior unique?” Make sure to use strict Given-When-Then step order when defining the behavior. Rethink the scenario if it is more than 10 lines long. Look out for unnecessary complication.
What does it mean for a scenario to be “chronological”?
Scenario steps should be written as if they were on a timeline. Each step will be executed after the previous one, so its description must start where the previous one ended. Remember, steps will be automated as if they were scripts.
How do we write a very low-level scenario without having a wall of text?
Don’t write low-level scenarios! Gherkin is best for feature testing, not unit testing. Steps should focus on intention and business value. Instead of writing “type, type, click, wait,” write “log into the app.” If you absolutely must write a low-level scenario, remember that the same principles apply. Be intuitively descriptive. Focus on individual behaviors. Keep scenarios concise.
If all scenarios in a feature file have only one user, is it okay to use first-person perspective instead of third-person?
In my opinion, no. I favor third-person perspective universally. Trying to limit usage to one feature file won’t work because any step can be used by any feature file within a test project. The entire solution must be either first-person or third-person. There’s no middle ground.
Can we write Gherkin scenarios with personas?
Yes! Personas can make scenarios more meaningful and understandable. Make sure to define the personas well – they could be described under the Feature section or in a separate text file.
How do we write Gherkin scenarios that need to validate lots of information on a page?
Pick the most important pieces of information to check. You could write separate Then steps for each assertion, or you could push small-but-similar validations down to the automation level to avoid Gherkin clutter.
How do we write Gherkin scenarios for validating Web UI fields?
Typically, I treat each field validation as an independent behavior, and thus I write separate scenarios to check each field. If the scenario steps simply enter a textual value and verify a specific message, then I might make a Scenario Outline with example rows for each equivalence class of inputs.
How do we write Gherkin scenarios that have multiple inputs and setup steps? (Example: an API with ten parameters)
Gherkin allows multiple steps of the same type to be written using “And” and “But” keywords. It’s not a problem to have “Given-And-And” or “When-And-And”. If you discover that different scenarios repeat the same setup steps, then I recommend either moving those common steps to a Background section or writing a new step that covers multiple calls (for conciseness).
One example from the webinar showed searching for shoes and adding them to a shopping cart as part of one scenario. Aren’t those two different behaviors?
Here’s the scenario in question:
Scenario: Add shoes to the shopping cart
Given the ShoeStore home page is displayed
When the shopper searches for “red pumps”
And the shopper adds the first result to the cart
Then the cart has one pair of “red pumps”
We could have split this scenario into two. I just chose to define the behavior this way. This scenario is a bit more end-to-end because it covers a basic but typical workflow. It may also have leveraged existing steps, which expedites automation development. Overall, the scenario is still concise, chronological, and intuitively understandable. Remember, there is an art as well as a science to writing good Gherkin.
Questions about Automation
Do scenarios need to be independent of each other?
Yes, unequivocally. Tests that are not independent could interfere with each other and cause unexpected failures. Independence also reinforces singular behavioral focus.
How do we start a scenario “in media res” without it depending on other tests?
At the Gherkin level, write Given steps that define a new starting point for the behavior. For example, many teams develop Web apps. It’s common to think that the starting point for all tests is login. However, the starting point can be a few pages after login.
At the automation level, it may be useful to implement the Given steps by calling other steps. For example, if a Given step should start at a user’s profile page, then perhaps it could internally call the login step and the click-the-profile-link step. Test steps may repetitively do the same operations for different tests, but test case independence will be preserved, and unique failures will be reported.
What is the best way to handle preconditions like logging into a Web app?
The simplest way to handle preconditions is to write Given steps. If those Given steps are shared by all scenarios in a feature file, then move them to a Background section. Automation hooks can also perform common setup and cleanup actions, depending upon the test framework. Personally, I prefer to use hooks to do automatic login rather than repeat Given steps for many scenarios.
Is it better to set up and tear down new test objects for each test case, or is it better to use shared, pre-created objects?
That depends upon the object. Most objects like WebDrivers and page objects should have scenario scope, meaning they are created fresh for each scenario and then torn down when the scenario ends. The only time an object should be shared across scenarios is if it is immutable or very expensive to create. For example, configuration data could be read in once before all tests and then injected immutably into each scenario. The safe position is always to use fresh objects; justify why sharing is needed before trying it.
I want to use Serenity for BDD and testing. Should I use Cucumber-like Gherkin feature files, or should I use Serenity’s native methods?
If a company already has a large BDD test solution that is poorly implemented, would it be better to keep it going or try to change it?
This question can be applied to all software projects, not just BDD test solutions. The answer is situational. Personally, I favor doing things right, even if it means refactoring. Please read Our Test Automation Has Problems. Should We Start Over? for a thorough answer.
Why do you call yourself “Pandy” and the “Automation Panda”?
Pandas are awesome. Everybody loves them. And nobody forgets my moniker. The nickname “Pandy” came about in the Python community to distinguish me from other folks named “Andy.”
Where can I get team training in BDD?
Beaufort Fairmont provides a one- or two-day course in BDD and writing Gherkin. Sign up for more information here.