asos tech community live: atdd
TRANSCRIPT
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Nik Crabtree
Principal Software Engineer for Digital Experience
Gareth Waterhouse
Lead QA Engineer for Content & Product
The Plan
It’s a what now?Shared Ownership
Shared UnderstandingTest-first
Acceptance CriteriaI Can Haz Demo
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It’s a what now?
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ATDD: Acceptance Test Driven Development
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It’s a three-legged race, not a relay
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We do Scrum
Scrum makes some very specific statements about ownership.
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Shared Ownership
“Scrum recognizes no titles for Development Team members other than Developer, regardless of the work being performed by the person; there are no exceptions to this rule.”
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Shared Ownership
http://www.scrumguides.org/scrum-guide.html#team-dev
“Scrum recognizes no sub-teams in the Development Team, regardless of particular domains that need to be addressed like testing or business analysis; there are no exceptions to this rule.”
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Shared Ownership
http://www.scrumguides.org/scrum-guide.html#team-dev
“Individual Development Team members may have specialized skills and areas of focus, but accountability belongs to the Development Team as a whole.”
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Shared Ownership
http://www.scrumguides.org/scrum-guide.html#team-dev
There are no heroes
The Development Team is responsible for every PBI in the sprint backlog.
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Shared Ownership
There is no ‘dev complete’
It’s done when it’s proven to meet all of the acceptance criteria.
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Shared Ownership
Not burning down to zero isn’t a failure
Throwing your team-mates under the bus is.
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Shared Ownership
One hymn sheet between two please
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{P} C {Q}
This is a Hoare Triple
Where P is a pre-condition assertion, C is a command and Q is a post-condition assertion.
If the pre-condition is met, executing the command establishes the post-condition.
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Shared Understanding
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{P} C {Q}
Ok, let’s put it another way…
Given the pre-condition P is met
When the command C is executed
Then it establishes the post condition Q
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Shared Understanding
A Hoare Triple
is a logical function to which we provide input, invoke an action
and examine the output.
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Shared Understanding
A Functional Test
is a logical function to which we provide input, invoke an action
and examine the output.
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Shared Understanding
A Unit Test
is a logical function to which we provide input, invoke an action
and examine the output.
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Shared Understanding
So…
We can write
Functional Tests
and Unit Tests
from the same
Acceptance
Criteria
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Shared Understanding
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Cats eyes for your development supercar
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Test-first is not…
A waste of valuable delivery time
All about code coverage
An opportunity to start a holy war
Just for software engineers
Boring
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Acceptance Criteria
Test-first is…
A way of engendering a lean approach to development (avoid gold-plating, over-engineering and breaking YAGNI)
A way of being confident that software meets requirements from the first line of code
All about understanding what you are doing and why
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Acceptance Criteria
Building from a solid foundation
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Acceptance Criteria should be…
Defined and agreed by the Development Team with the Product Owner
Written in a business readable, domain specific language, like Gherkin
Written from an Outside-In perspective
Expectations of behaviour, not implementation
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Acceptance Criteria
Practical ATDD
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Feature: Add SweetsIn order to populate the Sweets CatalogueAs a Sweets Catalogue ManagerI want to be able to add a new Sweet to the Sweets Catalogue
The Development Team discusses the story…
How do we pass credentials? What information does a new sweet contain? Are there any validation rules? What about duplicates? What if I send an empty request? What if the name is in a different case?
Feature: Get SweetsIn order to view a available sweet(s)As a Sweets Catalogue ReaderI want to be shown available sweet(s)And I want to be shown individual sweets
The Development Team discusses the story…
How do we pass credentials? What information does a new sweet contain? Are there any validation rules? What about duplicates? What if I send an empty request? What if the name is in a different case?
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