The Feedback Loop

Agile Development Processes (TDD, ATDD, BDD)

Why do we do Agile ?

A quick reminder

The V Model

Mismatched expectations

Communication is key

Communication is hard

Scrum: shorter feedback loops

Agile principles in your everyday life

Your dev workflow

- Read specs

- Write code

- Test the application

- Fix the bugs

- Test the application

- Ask QA to test the application

- Fix the bugs

- Ship the feature

How to shorten
the feedback loop

You NEED tests

Really

Non-Regression

• You can't trust the other devs... nor the future you ;)
• Am I breaking something ?

• getpremium.js, 1500 LOC of untested code
• Don't laugh, we all have at least one file like that ;)

Documentation

• Beneficial side-effect
• You're not alone, help other to understand by giving examples

Let's go further

Test Driven Development

Well, it's great in theory...

...but we are a startup, we don't have time for that!

You want to write
​your tests first

• It shortens your feedback loop / testing loop
  • You pay a cost upfront but you save time + other devs time
• Design ahead... and think twice before diving in this complex algorithm

Parenthesis: FIRST properties

• Fast
• Isolate
• Repeatable
• Self-verifying
• Timely

Is it only for unit testing?

No.

Acceptance Test Driven Development

• TDD at the feature level
• Think about all the back and forths you are doing with product and stakeholders
  • Miscommunication
  • Forgotten specs: error states, edge cases, ...

ATDD in practice

• QA and product write a list of scenarios for the story
• QA / dev write an automated test
• Dev implements the feature and make the tests pass

ATDD benefits

• Better communication : an automated scenario is clearer than a JIRA description
• Design ahead with Product Guy (forgotten states...)
• Less back-and-forths and more asynchronous work
• Non-Regression: did I break feature A while doing feature B ?
• Documentation: what is the product supposed to do?

ATDD at Dashlane

• Could be done on so many things!
  • Each feature
  • Installer & Usage logs
  • ...

What's the catch ?

BDD: one DD to rule them all

BDD principles

• Test => scenario or specification
• Natural language
• Focus on the business outcome (from the outside-in)
• Applicable at every level of the stack (Unit tests, Acceptance tests)

Emphasis on documentation

• Expected behaviors
• Everyone can collaborate (QA, product, dev)
• Readable by everyone
• Single source of truth

The feedback loop
is everywhere

• Development
• Product
• Business
• Management

Where do I start?

Thanks!