Cucumber - Data Driven Testing - Multiple Similar Steps In Same Scenario

I am writing a feature which deals with adding multiple items to shopping cart like a typical e-commerce application. It is something like this - Scenario: Promotion is applied

Solution 1:

Putting figures in scenarios is a really good way to dramatically increase the cost of change, whilst at the same time creating fragile tests with high maintenance costs. So don't do it.

In addition you are not clearly stating what you are testing and you are repeating yourself.

From what you have written I can see lots of different behaviour you might be specifying here.

You should write separate scenarios for these things. So you could have scenarios like

Scenario: Promotion affects all products in the basket
  Given a have a basket with several products
  And I have applied a promotion
  When I go to the checkout
  Then I should see a discount applied toeach product

Scenario: Some products are not discountable

to deal with the actual value of the discount

Scenario: Correct discount rate is applied for a promotion
  Given a promotion with a 20% discount
  And a basket of products
  When I go to the checkout
  Then I should see a 20% discount

etc. etc.

Note: Doing calculations like in your examples is a particularly effective way of making your scenarios expensive to maintain, and to increase the cost of change of your application.

Consider your example. It has several business rules hidden in the figures. Some of these probably are:

• lettuce is not discounted by promotions
• bacon is half price (or is that any quantity of bacon gets 50c off?) ...

Note how none of these rules a clearly specified in you example scenarios, you have to infer (guess) the rule from the example.

Now all of these are rules that must somehow be encoded in your application (hopefully in the promotion and products). What happens when

• lettuce becomes discountable
• bacon supplies are tight so you can't discount it any more

With your current approach what happens is that you tests fail and you have to re-write the scenarios to reflect your new business conditions - so you have dramatically increased the cost of change.

The simple rule for this stuff is don't put calculated numbers in scenarios. The fuller more complex rule is that all examples in scenarios should mature into concise verbal expressions of business rules. They should capture the WHAT i.e. that some products can have a percentage discount, rather than HOW i.e. bacon is currently 50c per pound cheaper. Then if someone makes the simple config change that bacon is no longer discountable you don't have your tests breaking because of this.

Solution 2:

A second answer is that

Cucumber is not a testing tool, if you want to write data driven tests use a testing tool like a unit test tool.