test-writer

Ask the user to share the function or code they want tests for.

Then write tests covering:

Tests for [functionName]

Testing framework: [detect from package.json — Jest, Vitest, pytest, etc. Ask if unclear]

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Happy path

Test the expected behavior with valid inputs. One test per meaningful variation.

test('returns [expected] when given [input]', () => {
  // arrange
  // act
  // assert
})

Edge cases

Tests for boundary conditions and unusual but valid inputs:

• Empty input (empty string, empty array, 0)
• Single item
• Maximum size or value
• Special characters (if string input)

Error cases

Tests that verify the function fails correctly:

• Invalid input types
• Null/undefined inputs
• Inputs that should trigger error handling

Mock requirements

List any external dependencies (API calls, database queries, file system) that need mocking, with example mock setup.

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Coverage target: Aim for all branches, not just lines. Flag any branch that is difficult to test and explain why.

Write tests that read like documentation — the test name should be a sentence explaining what the function does in that scenario.