Lexicon Spec Test Fixtures#

This directory contains test fixtures organized by ATProto Lexicon specification features, not by real-world examples.

Organization#

Each subdirectory focuses on a specific feature from the Lexicon spec:

• union/ - Union type features (open, closed, variants)
• string-constraints/ - String knownValues, enum, formats
• validation/ - Constraints (min/max length/value, graphemes)
• primary-types/ - Record, query, procedure, subscription
• field-types/ - Primitive types and their features
• refs/ - Reference patterns (local, cross-namespace)
• nullable/ - Nullable field handling
• unknown/ - Unknown type usage
• tokens/ - Token definitions and usage
• binary/ - Blob and bytes types
• evolution/ - Schema evolution patterns

Purpose#

Unlike test/scenarios/atproto/ which tests real ATProto lexicons, these fixtures:

1. Test each spec feature in isolation
2. Demonstrate minimal, focused examples
3. Serve as documentation for TypeSpec → Lexicon mappings
4. Catch edge cases and corner cases in the spec

Example Structure#

Each feature directory contains:

• input/*.tsp - TypeSpec definitions for that feature
• output/*.json - Expected Lexicon JSON output

Tests should be atomic and focus on one feature at a time.