Stop 04 · SDLC, Agile & Testing MethodologiesTopics · 7/9

Acceptance Test-Driven Development (ATDD)

In short

ATDD is like TDD, but the tests come from the customer's point of view and are agreed by business, developers and QA before anyone starts building.

Similar to TDD but focused on acceptance criteria defined collaboratively by QA, developers, and business stakeholders before development begins — ensuring everyone shares the same definition of 'done' upfront.

The purple blob shakes hands with a carpenter next to a half-built wooden wardrobe.

Think of it like this

Agreeing with the carpenter

Before the carpenter builds your wardrobe, you agree: it fits in this corner, holds 20 hangers, doors close without touching the bed. On delivery day you check exactly those things. Nobody argues about what 'done' means.

Watch it happen

The four Ds of ATDD

Discuss

Distill

Develop

Demo

1/4Business, developers and QA discuss the story and collect real examples of expected behaviour.

The big ideas

What you need to know

Team-written tests

Acceptance tests are agreed together before development, not invented by QA afterwards.

Customer's view

TDD tests code units. ATDD tests whole behaviours the customer cares about.

Close cousin of BDD

BDD is a style of ATDD with Given/When/Then wording. Many teams use the terms loosely.

See it in code

Walk through the code

text

1Story: Late fee on library books2 3Days late   Member type   Expected fee40           Student       Rs 053           Student       Rs 1563           Staff         Rs 0730          Student       Rs 100 (capped)

1/3Columns are the inputs and the expected result.

An example table agreed in the Discuss step. Each row becomes one acceptance test.

Save yourself the pain

Common mistakes

Oops

QA writing acceptance tests alone after the feature is built.

Do this instead

Write them together before development, so they guide the build instead of judging it.

Oops

Using vague criteria like 'fees are calculated correctly'.

Do this instead

Use concrete example rows with real numbers anyone can check.

Your mission

Run a mini Discuss and Distill

~20 min

Quick check

What's the main difference between TDD and ATDD?

Go deeper

1Draft acceptance criteria collaboratively (in your head, simulating multiple stakeholders) for a feature.
2Learn why ATDD's upfront collaboration reduces late-stage requirement disputes.
3Compare ATDD, BDD, and TDD and note how they overlap and differ in focus.