Business Rules - Testing & QA

This document lists the fundamental business rules of the Testing & QA domain, identified with a unique BR-NNN code. Each rule is technology-independent and describes an invariant constraint on the software quality verification process.

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BR-001 - Every TestCase has a verifiable oracle

Code: BR-001 Name: A TestCase defines an unambiguous expected outcome Description: Every test case has an explicit test oracle (the expected outcome) and assertions that verify it, typically in Arrange-Act-Assert structure. A test without meaningful assertions or without an expected outcome verifies nothing. Motivation: Ensure a test fails when behaviour is wrong and passes when it is correct. Priority: HIGH Actors: QA Engineer, Test Automation Engineer Traceability: glossary "Test Oracle", "Assertion", "Arrange-Act-Assert (AAA)"; BC-01.

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BR-002 - The suite respects the test pyramid

Code: BR-002 Name: The test distribution follows the pyramid (many unit, few E2E) Description: A TestSuite favours a wide base of fast unit tests, an intermediate level of integration tests and a small tip of end-to-end tests. Inverting the pyramid (many slow E2E) is an anti-pattern to avoid. Motivation: Maximise feedback speed and reliability while minimising fragile tests. Priority: HIGH Actors: QA Engineer, Test Automation Engineer Traceability: glossary "Test Pyramid", "Unit Test", "End-to-End Test (E2E)".

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BR-003 - Flaky tests are fixed or isolated

Code: BR-003 Name: A Flaky Test does not stay in the gate suite Description: A test that passes and fails non-deterministically erodes trust in the suite. It must be fixed (removing the source of non-determinism) or temporarily isolated and tracked, never silently ignored. Motivation: Preserve trust in results and the gate's ability to block real regressions. Priority: HIGH Actors: Test Automation Engineer, QA Engineer Violation: a suite with non-isolated flakies is not reliable as a release gate. Traceability: glossary "Flaky Test"; events/domain-events.md event RegressionDetected.

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BR-004 - Every defect is recorded as a traceable BugReport

Code: BR-004 Name: A detected Defect (Bug) generates a reproducible BugReport Description: Every defect is recorded with reproduction steps, expected and observed behaviour, severity and environment. A non-reproducible bug is triaged to obtain information, not silently closed. Motivation: Make every defect manageable, prioritisable and verifiable at closure. Priority: HIGH Actors: QA Engineer, Developer Traceability: glossary "Defect (Bug)"; state-machines/bug-report-lifecycle.md; BR-007.

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BR-005 - Modified code is covered by a regression test

Code: BR-005 Name: A fix includes a regression test that captures the defect Description: When a BugReport is resolved, a RegressionTest that fails before the fix and passes after is added to the suite. This prevents the same defect from returning. Motivation: Prevent the regression of already-fixed defects. Priority: HIGH Actors: Developer, Test Automation Engineer Traceability: glossary "Regression Test"; state-machines/bug-report-lifecycle.md verified state; BR-004.

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BR-006 - Coverage is meaningful, not just numeric

Code: BR-006 Name: The CoverageReport measures tested behaviour, not just executed lines Description: Coverage is a tool, not a goal: a threshold acts as a guardrail but high coverage with weak assertions does not protect. Edge cases, equivalence partitions and negative scenarios are prioritised. Motivation: Avoid the false security of high but empty coverage. Priority: MEDIUM Actors: QA Engineer, Developer Traceability: glossary "Code Coverage", "Boundary Value Analysis", "Equivalence Partitioning", "Negative Test".

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BR-007 - A release passes only with a green quality gate

Code: BR-007 Name: A release requires a green TestSuite and no open blocking bugs Description: The ReleaseGate is passed only when the suite is green, coverage respects the threshold and no blocking-severity BugReport are open. A failed gate blocks the release. Motivation: Ensure only verified software reaches production. Priority: HIGH Actors: Release Manager, QA Engineer Violation: release blocked until the gate is green. Traceability: glossary "Smoke Test", "Quality Assurance (QA)"; events/domain-events.md event ReleaseGatePassed.

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BR-008 - Tests are independent and repeatable

Code: BR-008 Name: Every TestCase is isolated and does not depend on execution order Description: Tests do not share mutable state nor depend on the outcome of other tests. Each sets up (Fixture) and cleans up its own context, so it can run in isolation and in parallel with a deterministic outcome. Motivation: Guarantee repeatable, parallelisable results, prevent flakiness from coupling. Priority: HIGH Actors: Test Automation Engineer, QA Engineer Traceability: glossary "Fixture", "Test Fixture", "System Under Test (SUT)"; BR-003.