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Show HN: Mirrors – test AI agent changes by replaying production traces
23 days ago
- Mirrors converts production traces into an isolated copy of an agent's environment for safe testing.
- It rebuilds schemas, discovers tools, and provides a runnable copy with seeded databases and scored tool matches.
- Enables replaying agents consistently to measure accuracy, catch regressions, and ensure changes work before deployment.
- Offers deterministic, byte-identical worlds for reliable failure reproduction without touching production systems.
- Supports on-demand launch, scaling to zero, per-minute metering, and integration via a versioned API and workspace keys.
- Provides free building with deterministic seeding, with Custom plans for unlimited sandboxes, API access, and SSO.
Tests Are SQL Files Too
21 days ago
- NpgsqlRest 3.12.0 introduced SQL files as REST endpoints, eliminating deployment and migration needs.
- NpgsqlRest 3.19.0 enhances this with named parameters, watch mode for real-time validation, and a native test runner.
- Test runner uses SQL files with embedded HTTP comments for in-process endpoint testing, with automatic rollback for isolation.
- PostgreSQL features like transactional DDL, deferrable constraints, and cheap database creation make database testing feasible.
- Watch mode provides continuous validation and re-runs tests on save, improving development experience.
- AI TDD is enabled by fast, isolated tests with truthful feedback loops for AI agents.
OpenCQRS 2.0: Tests That Read Like the Domain
20 days ago
- OpenCQRS 2.0 introduces a fluent Given/When/Then DSL that makes event-sourced tests read like domain specifications, acting as documentation that can't rot.
- Event sourcing changes testing by reducing ceremony, eliminating the need for mocks, and allowing tests to mirror command handlers as pure functions with events as inputs and outputs.
- The framework enforces consistency through preconditions like SubjectIsPopulated and EventQlQueryIsTrue, ensuring tests align with database-enforced business rules.
- The update includes modernizations like Spring Boot 4.1, Jackson 3, Gradle 9, EventSourcingDB 1.2 support, and JSpecify annotations for better null-safety.
- OpenCQRS 2.0 also adds features like readSubjects for hierarchical stream discovery and improved handling of deterministic time in tests for temporal domain rules.

testing

Show HN: Mirrors – test AI agent changes by replaying production traces

Tests Are SQL Files Too

OpenCQRS 2.0: Tests That Read Like the Domain