Add executable tests to low-coverage modules

Why use this

1. A low coverage score identifies unexercised code but does not say which behaviours deserve protection. Tests can raise the number while simply reproducing implementation details, missing the failure cases that make future changes risky.

2. This job could give engineers a focused test proposal tied to observable contracts and important branches. The review should explain what each test protects and which dependencies remain simulated, making the contribution useful beyond a coverage increase.

Why an agent / simpler alternative

Useful judgment

Infer candidate behaviours from code and documentation and design edge cases for engineer review.

Simpler alternative

Write a small manual test when the contract is narrow and well understood.

Unsuitable when

Expected behaviour is disputed or tests require production credentials and side effects.

Proposed inputs

1. Name

   Scoped module snapshot

   Owner

   Repository owner

   Minimum scope

   Assigned files, dependency interfaces and existing test conventions

   Quality check

   Use a known revision and identify externally visible contracts.

2. Name

   Test priorities

   Owner

   Engineer

   Minimum scope

   Relevant defects, unsupported inputs and desired regression protection

   Quality check

   Separate documented expectations from current accidental behaviour.

Access and setup — proposed or unknown

Proposed minimum

1. Inspect an authorized repository copy and propose isolated tests with fake dependencies.

Compatibility unknowns

1. Unknown: test runner, dependency versions, fixture support and runtime compatibility.

External actions requiring approval

1. Installing dependencies, executing side-effecting tests, opening PRs or changing production code.

Expected deliverable and review checks

Proposed artifact

Reviewable test patch with behavioural rationale, fixture descriptions and execution status.

Critical checks

1. Assertions would detect the targeted defect rather than echoing implementation outputs.

2. Network, clock and filesystem effects are isolated or explicitly blocked.

Missing output evidence

No new run or output inspection in this editorial layer; see linked source-specific limits.

Failure signals and proposed responses

1. Signal

   A mock returns the exact value the test asserts without exercising the module.

   Why it matters

   The test may pass while the behaviour is broken.

   Proposed response

   Trace the assertion to real module logic and simplify the mocked boundary.

2. Signal

   Tests depend on the wall clock or execution order.

   Why it matters

   Intermittent failures undermine confidence and slow review.

   Proposed response

   Use controlled time and independent fixtures; expose any unavoidable nondeterminism.

Effort and cost — unknown

Setup work

1. Identify contracts and establish isolated fixtures.

Ongoing review

1. Review test meaning and maintain fixtures as interfaces change.

Unknowns

1. Unknown: environment setup, CI resources and engineer review effort.

First check — proposed, unexecuted

Status

proposed_unexecuted

Synthetic fixture

Synthetic module specifications describe empty input, malformed input and a simulated dependency failure.

Acceptance checks

1. Each proposed test names an expected observable outcome.

2. No fixture reaches a real service or needs credentials.

Stop conditions

1. The contract must be guessed or production side effects cannot be isolated.

Limits

1. Useful tests reduce specific uncertainty; coverage percentages alone do not establish correctness or complete protection.