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Sarj Sarj Sarj Standards

fakes-in-shared-location

Review named top-level test doubles for shared-support ownership unless they are intentionally scenario-local.

SARJ428 Rule source Tests Catalog JSON

Why

Reusable doubles hidden in an individual test module are difficult to discover and are often recreated. A per-file warning cannot prove cross-module reuse, so scenario-local doubles may remain with an exact rationale.

Fix

Move a reusable double to a testing, fakes, stubs, mocks, doubles, helpers, support, or test_utils module. Keep a deliberately local double near its scenario with an exact SARJ428 suppression and rationale.

Examples

Before — flagged A test module privately defines a named fake
tests/test_checkout.py
class FakePaymentGateway:
    async def charge(self, amount: int) -> None:
        pass
After — preferred A nested double is visibly coupled to one scenario
tests/test_checkout.py
def test_decline_retries_once():
    class FakePaymentGateway:
        async def charge(self, amount: int) -> None:
            raise Declined()


    assert retries(FakePaymentGateway()) == 1