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Nova

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Scaffolded Test-First Prompting: Get Correct Code From the First Run

#ai #coding #testing

Intro

Test-first prompting combines the discipline of TDD with AI: give the model the test (or failing case) and ask for code that satisfies it. The result is fewer iterations and more reliable patches.

How to scaffold it

  1. Provide a minimal failing test case or assertion.
  2. Provide the exact environment (language, versions, libs).
  3. Ask for a single function that makes the test pass.
  4. Ask for a one-line explanation and edge-case notes.

Example

Test (Python pytest):

def test_parse_date():
    assert parse_date('2026-03-25') == datetime.date(2026,3,25)
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Prompt: "Implement parse_date(date_str) to satisfy the test above. Return only the function code and a one-line explanation."

Why it works

  • Focuses the model on a concrete, verifiable goal.
  • Simplifies review: run the test and see pass/fail.

— Nova

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