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Introducción a BDD Carlos Blé Postgrado de Métodos Agiles - La Salle

Behavior Driven Development - Material de clase PMA

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Introducción a BDD

Carlos Blé Postgrado de Métodos Agiles - La Salle

Problem Domain Vs Solution Domain

Problem

SolutionSolution

SolutionSolution

SolutionSolution

WHAT HOW

Solution Domain

GUIGUI DatabaseDatabase

MockupsMockupsPrototypesPrototypes

Data StructuresData Structures

APIAPI

ScreenshotsScreenshots

Other appsOther appsProcessesProcesses

Context & Goals

Practices = Principles(Context) (Dan North)

Startup company: Don’t even know its market! The goal is to learn about customers

Tailored software tools: The problem is well-known Business doesn’t change often!

Problem discovery tools

Examples, examples, examples!

A deep understanding of the business is a must

● Specification workshops● Impact mapping

● Mind maps● User stories

● User story mapping● Example mapping

● Event Storming● Gherkin

Recommended authors: Gojko Adzic

Specification workshops

1.Conversation with examples (no Gherkin)

2.Acceptance criteria definition.

3.Write down some scenarios.

4.Refine the scenarios (sometimes Gherkin).

5.Remove redundant examples/scenarios.

The Three Amigos

Separate the “What” from the “How”

The way to go fast is to avoid waste

Everything seems to be solved with CRUD... but in the end it’s pretty much never a CRUD!

Every line of code is a commitment

Defer implementation details as much as you can.

Reverse engineering is sometimes required to discover the problem from the solution

Known or proposed solutions are welcome as long as...

Works for us

Short user stories we can develop in two days.

Vertical user stories.- non-explicit technical stuff

Business valuable examples. - no state

Separate acceptance criteria from scenarios.

Deliver new features every week or two weeks.

Direct access to each other to ask questions face to face at any time.

Hexagonal Architecture (ports & adapters)

Combine Cucumber with other tools (xUnit, RSpec flavored frameworks)

Mind maps: plan and prioritize

Works for us

Specification workshops

Don't worry about scenarios automation

Observe the users interact with our software

Meet the users after every release

Works for us

What happens with the GUI?

UI workshops: 3 Roles: UX, Developer, Analyst

User stories often contain GUI “suggestions” or “guidelines”

GUI should not add unnecessary constraints

Examples Vs Acceptance Criteria

Examples helpto understandthe business, and remove ambiguity

But acceptance criteria requires a higher level of abstraction

See the forest for the trees

Acceptance criteria are a quick summary to help us understand...

● what do we really want? the desired behavior of the system

● how to demo? when is the feature done

● documentation: the implemented behavior

As garage organiserI want to assign jobs to mechanicsTo balance the workload in the garage

Acceptance Criteria:

- Jobs are assigned to a single mechanic on a particular day without specifying the start time

- Jobs have different priorities

- Ongoing jobs can't be assigned from one mechanic to another

- A finished job can't be assigned to any other mechanic

Background:“Paco” is a mechanic

Scenario: Assign job to mechanicGiven the job "Change pad brakes" is in the unassigned work queueAnd “Paco”'s agenda for tomorrow is emptyWhen the organizer assigns the job to “Paco” for tomorrowThen the first thing for him to work on tomorrow is that jobAnd the job is no longer in the unassigned work queue

Scenario: Prioritize jobs Given “Paco”'s queue for tomorrow contains "Change oil" & “Inspection”When the organizer prioritizes the job “Inspection” for “Paco”Then  first thing for him to work on tomorrow is “Inspection”

Scenario: Ongoing jobs can't be reassignedGiven that “Paco”'s is working on "Inspection”When the organizer tries to assign the job to another mechanicThen  the organiser is told that “Paco” is already working on that jobAnd   it remains assigned to “Paco”

Scenario: Finished jobs can't be reassignedGiven that “Paco” is done with job “Change pad brakes”When the organiser tries to assign it to another mechanicThen  the organiser is told that job is finished and can't be reassigned

Notes:- Mechanic agenda is stored in table T in the legacy system.

UX Suggestions:- Drag & drop could be a good metaphor for the assignments

Do we need scenarios for this one?

As garage organiserI need to know what jobs are in the queue To assign jobs to mechanics

Acceptance Criteria:

- Jobs are in the queue when: - they are not assigned to a particular mechanic and the car is in the garage. - the job doesn't require a pending steering part.

Recap

Acceptance criteria specify what should be done

Examples help understand the criteria

Additional information may be useful

When an acceptance criterion is a long line...

When an example doesn't reveal the criterion...

7

E

AC AC

AC

E E

Heuristic

Separate types of tests

Documentation tests - Cucumber - Nunit with specific tags (attributes):        [Test]        [Specification]

        public void …()

Triangulation tests - Integration and unit tests - Nunit, Webdriver...

Automation

Even if we don't automate the scenarios...

Cucumber scenarios don't have to be integration tests.

Sometimes xUnit/RSpec frameworks are enough.

Automation often require little changes in the scenarios...

Avoid complex test setup

Green field Vs Legacy

Test-first let us aim for the best design. Perfect for green field projects.

Test-first does not help much when a big chunk of the system is already designed though

We love feedback!

Features are not real until they go live and users embrace them. Don't plan too far away!

Conclusion: listen to your users!

Release Feedback

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