PyTest - Writing Assertions
You want to test if a list of floating numbers is approximately equal to expected values with a tolerance of 0.01. Which is the best way to write the assertion?
You want to test if a list of floating numbers is approximately equal to expected values with a tolerance of 0.01. Which is the best way to write the assertion?
hard🚀 Application Q8 of 15
Step-by-Step Solution
Solution:
Step 1: Understand absolute vs relative tolerance
abs=0.01 sets an absolute tolerance, suitable for fixed margin comparisons.Step 2: Check options for list comparison
pytest.approx supports list comparisons with abs parameter. assert actual_list == pytest.approx(expected_list, abs=0.01) uses this correctly. assert actual_list == pytest.approx(expected_list, rel=0.01) uses relative tolerance which may not fit fixed margin. assert all(abs(a - e) < 0.01 for a, e in zip(actual_list, expected_list)) is manual but less concise. assert actual_list == expected_list requires exact equality.Final Answer:
assert actual_list == pytest.approx(expected_list, abs=0.01) -> Option AQuick Check:
Use abs= for fixed tolerance in list approx comparison [OK]
Quick Trick: Use abs= for fixed tolerance in pytest.approx [OK]
Common Mistakes:
MISTAKES- Using rel= when abs= is needed
- Not using pytest.approx for list comparison
- Expecting exact equality for floats
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