How to increase reusability between SpecFlow/Gherkin steps?

问题

I think I thoroughly understand the concepts and ideas behind SpecFlow, but even after reading the Secret Ninja Cucumber Scrolls, The Cucumber Book, and going through the various forums I'm still unsure about the path to reusability.

Our scenarios already comply to various guidelines

Self explanatory
Must have a understandable purpose (what makes it different from the other scenarios)
Are unique
Represent vertical functional slices
Uses Ubiquitous Language
Written from the stakeholder perspective
About business functionality, not about software design
Grouped by Epics
ARE NOT TEST SCRIPTS
Let somebody else read them to see if the scenario is correct
Doesn't refer to UI elements
Represent key examples
Non-technical
Precise and testable
As repeatable as possible
'Given' represent state, not actions
'When' represent actions
'Then' should represent a visible change, not some internal event

Our steps have to comply to the following guidelines (some are specific to SpecFlow):

Uses Ubiquitous Language
Doesn't refer to UI elements
Should not be combined
Should be reusable and global over all features
Should not be linked to a specific feature
Grouped by entities, entity groups or domain concepts
Don't create steps to reuse logic in a step definitions file
Think thoroughly in what Steps file a step belongs
Don't reuse steps between phases
Literal strings in steps must be avoided, but if required use single quotes
Never apply multiple [Given], [When] or [Then] attributes to the step method
Order the steps according to the phase they represent
If it is not important for the scenario, it is very important not to mention it

But we still end up with lots of variations of the same steps, even if we use regex placeholders. Especially the rule that if something is not important, you shouldn't mention it results in those variations. And yes, internally these steps do a lot of reusing, but not in the scenario.

Consider for example the following scenario:

Feature: Signing where both persons are physically available

@Smoke
Scenario: Show remaining time to sign based on previous signature
  Given a draft proposal
  And the first signature has been set
  When I try to set the second signature
  Then the remaining time to sign should be shown

@Smoke
Scenario: Re-signing of the first proposal
  Given a signature that has not been set within the configured time
  And the first signature has just been re-signed
  When I try to set the second signature
  Then the remaining time should start over

Would it be better to combine the two 'given' steps into one and loose some reusability?

Some other examples:

Feature: Conditionally show signatures to be signed

@Smoke
Scenario: Show the correct signature for a proposal with a night shift
  Given I have a proposal for the day shift
  When I change it to the night shift
  Then I should only be able to sign for the night shift

@Smoke
Scenario: Show additional signature when extending the shift
  Given I have a suspended proposal for the night shift
  When I extend the period to the day shift
  Then I should confirm extening the period over the shift

Am I missing a fundamental concept here?

回答1:

This is not an answer, but some hints:

you can put multiple Given/When/Then attributes on the same method. If the parameters are the same and the difference is only in phrasing, this can be useful
in many project we use driver/page object pattern, so the step definitions are usually quite short (2-3 lines), so we bother less about the number of them
I like your scenarios, I would not change them. On the other hand try to focus on the readability and not the reusability. If your language is consistent, the reusability will come.
For increasing the reusability especially when there are a lot of "variations" of the entity you are talking about, you can consider using the step argument transformations. Here is an example:

you need a class to represent a permit in the tests with decorations:

class PermitDescription{
  bool suspended;
  bool draft;
}

create converter methods:

[StepArgumentTransformation("permit")]
public PermitDescription CreateSimple(){
  return new PermitDescription();
}
[StepArgumentTransformation("draft permit")]
public PermitDescription CreateDraft(){
  return new PermitDescription() { draft = true; }
}
[StepArgumentTransformation("suspended permit")]
public PermitDescription CreateSuspended(){
  return new PermitDescription() { suspended = true; }
}

you can have now more flexible step definitions that require permits:

[Given(@"I have a (.*) for the day shift")]
public void Something(PermitDescription p)
{ ... }

that matches to:

Given I have a permit for the day shift
Given I have a draft permit for the day shift
Given I have a suspended permit for the day shift

of course this is tool that can be also abused, but in some cases it can help.

回答2:

Adding onto the answer from @gaspar-nagy It follows the pattern of class design in C programming. Anywhere a common group of classes share common properties/methods, those properties/methods can be refactored into a base class.

What it looks like in our SpecFlow tests is that common browser operations are in the base classes:

Login()
Logout()
NavigateToUrl(string url)
UserHasPermission(string permission)
WaitForElementToAppearById(string id)
WaitForElementToAppearByClass(string class)

And each of those methods could have 1 or more Given/When/Then attributes like @gasper-nagy stated.

Another technique which proves invaluable is to share variables between .features and their respective C# step files is to use the ScenarioContext.

For example, whenever Login() is called to initiate our browser based tests, we do this:
ScenarioContext.Current.Set<IWebDriver>(driver, "driver")

Then anywhere else that needs the driver, can get it by:
var driver = ScenarioContext.Current.Get<IWebDriver>("driver")

This makes steps re-usable, such as user input tests for validation you may decide to pass the element being validated around like this: ScenarioContext.Current.Set<IWebElement>(element, "validation-element")

来源：https://stackoverflow.com/questions/11418074/how-to-increase-reusability-between-specflow-gherkin-steps

标签

cucumber

bdd

specflow

acceptance-testing

gherkin