test-coverage

===TEST_COVERAGE=== META: TYPE::SKILL VERSION::"1.0" STATUS::ACTIVE PURPOSE::"Python pytest coverage analysis, gap identification, and TDD workflow for achieving 90%+ coverage" DOMAIN::ATHENA[quality]⊕ARTEMIS[precision_targeting]

§1::WHEN_TO_USE TRIGGERS::[ "Analyzing coverage reports and identifying gaps", "Planning tests to achieve 90%+ coverage targets", "Understanding uncovered line categories", "Applying TDD discipline to fill gaps systematically" ] COMPLEMENTARY::[test-infrastructure,test-ci-pipeline,testing]

§2::ANALYSIS_PROTOCOL STEP_1::RUN_COVERAGE[ COMMAND::"pytest --cov=src/{module} --cov-report=term-missing", OUTPUT::[Stmts::total,Miss::uncovered,Cover::percentage,Missing::line_numbers] ] STEP_2::CATEGORIZE_GAPS[ A::VALIDATION_PATHS[HIGH::security_critical,"raise ValueError('...')"], B::EDGE_CASES[MEDIUM::behavioral,"if not items: return None"], C::ERROR_HANDLERS[MEDIUM::defensive,"except OSError: logger.warning(...)"], D::INFRASTRUCTURE[LOW::diminishing_returns,"logger.debug(...)"] ] STEP_3::PRIORITIZE[ORDER::A→B→C→D,"Security first, then behavioral, then defensive, then optional"]

§3::TEST_PATTERNS VALIDATION_PATH::[ PATTERN::"Test invalid inputs raise appropriate exceptions", TEMPLATE::"def test_{fn}rejects{case}(): with pytest.raises({Error}): {fn}({invalid})" ] EDGE_CASE::[ PATTERN::"Test boundary conditions and None/empty handling", TEMPLATE::"def test_{fn}handles{edge}(): assert {fn}({input}) == {expected}", COMMON::[None,empty_string,empty_list,zero,negative,max_value] ] ERROR_HANDLER::[ PATTERN::"Mock dependencies to trigger exception paths", TEMPLATE::"with patch.object({T}, '{m}', side_effect={E}): assert {fn}(...) == {fallback}" ]

§4::TARGETS THRESHOLDS::[ 90%::MINIMUM[quality_gate], 95%::RECOMMENDED[comprehensive], 100%::ASPIRATIONAL[critical_paths_only] ] CRITICAL_PATHS::[security_validation,auth,data_transformation,public_api] ACCEPTABLE_GAPS::[platform_specific,debug_logging,rare_defensive_handlers,third_party_errors]

§5::TDD_DISCIPLINE RED_GREEN_REFACTOR::[ RED::"Write failing test that exercises uncovered line", GREEN::"Verify test passes (line already implemented)", REFACTOR::"Improve test clarity" ] COVERAGE_ADAPTATION::[ DIFFERENCE::"Code exists, tests retroactive", APPROACH::"Write test FIRST, verify covers target line", VERIFICATION::"Run --cov before/after" ] GIT_EVIDENCE::"test({module}): improve coverage from X% to Y%"

§6::COMMANDS BASIC::"pytest --cov=src/{module}" TERM_MISSING::"pytest --cov=src/{module} --cov-report=term-missing" HTML::"pytest --cov=src/{module} --cov-report=html" FAIL_UNDER::"pytest --cov=src/{module} --cov-fail-under=90" SPECIFIC::"pytest tests/unit/{path}/test_{file}.py --cov=src/{path}/{file}" BRANCH::"pytest --cov=src/{module} --cov-branch"

§7::COMMON_PATTERNS RECOGNITION::[ EARLY_RETURN::"if not x: return None"→test_with_falsy, EXCEPTION_RAISE::"raise ValueError(...)"→test_invalid_expect_raises, EXCEPT_BLOCK::"except {E}: logger.warning(...)"→mock_to_raise, FALLBACK_PATH::"else: return default"→test_else_condition, LOOP_CONTINUE::"if not cond: continue"→include_failing_item, OS_ERROR::"except OSError: pass"→mock_file_op_to_raise ]

§8::ANTI_PATTERNS COVERAGE_THEATER::[ SYMPTOM::"Tests exercise code but don't assert behavior", EXAMPLE::"def test_fn(): fn() # no assertions", REMEDY::"Every test must have meaningful assertions" ] OVER_MOCKING::[ SYMPTOM::"Mock so much tests prove nothing", EXAMPLE::"Mock all deps, assert mock called", REMEDY::"Mock only external boundaries" ] CHASING_100::[ SYMPTOM::"Excessive effort for marginal gains", EXAMPLE::"Complex mocks to hit debug log", REMEDY::"Accept 95% with documented gaps" ]

§9::WORKFLOW STEPS::[ 1::"Run pytest --cov with term-missing", 2::"Identify highest-priority gaps (A→B→C→D)", 3::"Write targeted tests per category", 4::"Verify improvement after each batch", 5::"Commit: test({module}): improve coverage", 6::"Document remaining acceptable gaps" ]