go-test-implementationlisted

# Go Test Implementation Write tests that reject wrong behavior through an observable independent of the implementation being tested. Routine tests alongside production code stay with `go-coder`; this method handles test-only work or non-routine controls. Choose cases, fixtures, assertions, and commands while writing the tests from accepted product behavior and existing repository patterns. No pre-approved scenario, oracle, matrix, or separate test plan is required. Use the smallest deterministic layer that observes the claim. A source-string assertion proves behavior only when the exact text is itself the accepted output contract. For a new integration scenario family, write one complete path through state creation, the operation, independent observation, and cleanup before expanding cases. Reuse that foundation while binding each case to its own inputs. An existing valid scenario already supplies this foundation; do not rebuild it. The active workflow decides when the scenario runs. Load the [reference selector](references/index.md) only for a concrete problem with the proving layer, fixture, control, or command. Keep the result in test code and any existing task packet; add no proof-design artifact. This method is complete when required tests and fixtures are written and their execution commands are recorded. The active workflow and [Evidence Contract](../../../docs/spec-first-workflow/shared/evidence-contract.md) own validation timing and task completion. Missing tes