Module 5 · Python for SDETs

Test data
setup & teardown

Every test starts from a state you control — and leaves no mess behind

reset baseline arrange via API yield teardown factory fixtures
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The flakiness you can't reproduce

Tests that share state fail in ways you can't reproduce

🔀

Order-dependent

test B only passes if test A ran first — reorder and it breaks.

👻

Leftover data

yesterday's order or user lingers and skews today's assertion.

🎲

Green then red

the same test passes solo, fails in the suite — the classic flake.

🎯The fix: each test owns its state — start from a known baseline, set up exactly what it needs, clean up after.
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Known slate, every time

Reset to a known baseline

POST /api/reset
→
seed data restored ✅
→
your test runs on a clean slate
@pytest.fixture
def reset_db(base_url):
requests.post(f"{base_url}/api/reset")
yield # test runs here, on fresh data
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Arrange via the API, not the UI

Need a logged-in user with an order? Don't click through signup → login → checkout. POST the data straight in — one fast, reliable call — then test the thing you actually care about.

⚡API setup is faster and far less flaky than driving the UI to build state.
# arrange: one API call, not 6 UI clicks
order = api.post(
f"{base_url}/api/orders",
json={"email": user, "items": […]},
).json()
# act + assert on what matters
assert order["total"] == pytest.approx(59.98)
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Set up before yield, clean up after
@pytest.fixture
def temp_product(api, base_url):
# setup
p = api.post(…/products).json()
yield p # hand it to the test
# teardown — always runs
api.delete(f"…/products/{p['id']}")
♻️Code before yield is setup; code after is teardown — and it runs even if the test fails.
🏭Need several? A factory fixture returns a function the test calls N times — each with a unique name, and reset_db reseeds it all away after.
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♻️

Own your
test state

Reset the baseline, arrange through the API, and let fixtures clean up

🧪
Practice
A reset_db fixture + arrange an order via the API and assert its total
🏭
Factory
A factory fixture that makes N products, each with a unique name
➡️
Module 6
UI automation — drive the browser with Playwright for Python
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← / → · space