Test Optimization

Advanced test optimization with cargo-nextest, property testing, and benchmarking.

cargo-nextest (Primary Test Runner)

cargo nextest run --all # all tests cargo nextest run --profile ci # CI with retries + JUnit XML cargo nextest run --profile nightly # extended timeouts cargo nextest run -E 'package(memory-core)' # filterset DSL cargo test --doc --all # doctests (nextest limitation)

Configuration (.config/nextest.toml)

[profile.default] retries = 0 slow-timeout = { period = "60s", terminate-after = 2 } fail-fast = false

[profile.ci] retries = 2 slow-timeout = { period = "30s", terminate-after = 3 } failure-output = "immediate-final" junit.path = "target/nextest/ci/junit.xml"

[profile.nightly] retries = 3 slow-timeout = { period = "120s", terminate-after = 2 }

Mutation Testing (cargo-mutants)

Verifies tests actually catch bugs by injecting mutations:

cargo mutants -p memory-core --timeout 120 --jobs 4 -- --lib

• Acceptance: <20% missed mutants in core business logic

• Frequency: Nightly CI or pre-release

• Scope: Start with memory-core, expand incrementally

Property-Based Testing (proptest)

proptest! { #[test] fn serialization_roundtrip(episode in any_episode_strategy()) { let bytes = postcard::to_allocvec(&episode).unwrap(); let decoded: Episode = postcard::from_bytes(&bytes).unwrap(); assert_eq!(episode, decoded); } }

Snapshot Testing (insta)

#[test] fn test_mcp_response_format() { let response = build_tool_response("search_patterns", &params); insta::assert_json_snapshot!(response); }

cargo insta test # run snapshot tests cargo insta review # accept/reject changes

Performance Targets

Operation Target Actual

Episode Creation < 50ms ~2.5 µs

Step Logging < 20ms ~1.1 µs

Pattern Extraction < 1000ms ~10.4 µs

Memory Retrieval < 100ms ~721 µs

Best Practices

• Use nextest profiles for dev/CI/nightly separation

• Implement property tests for serialization roundtrips and state machines

• Use snapshot tests for MCP responses, CLI output

• Run mutation testing before releases

• Monitor test duration and coverage trends

References

• ADR-033: Modern Testing Strategy

• TESTING.md