Tests, ADR, and Input Format

[darinkishore]

Summary

Adds comprehensive test coverage, documents architectural decisions in an ADR, and implements input format control for typed signatures.

Tests Added

Integration tests (typed_integration.rs):

• Happy path with metadata access
• Check constraint recording (soft failures)
• Assert constraint failures (hard failures)
• Missing field error handling
• Integer parsing edge cases

Input format tests (test_input_format.rs):

• YAML/JSON/TOON format verification
• Alias preservation across formats
• Default format behavior (strings raw, others JSON)

Trybuild compile-fail tests:

• Duplicate #[format] rejection
• Invalid format values
• #[format] on output fields

ADR Coverage

Documents 9 key architectural decisions:

1. Three generated structs pattern for derive compatibility
2. ToBamlValue for prompt rendering
3. Function pointers for TypeIR in FieldSpec
4. ParseError::Multiple with partial results
5. Marker protocol [[ ## field ## ]]
6. BamlValue as optimizer interchange
7. Check vs Assert constraint semantics
8. Separate ToBamlValue trait design
9. Removal of PromptParts trait

Input Format Feature

#[derive(Signature)]
struct MySignature {
    #[input]
    #[format("yaml")]  // or "json", "toon"
    context: MyStruct,

    #[output]
    answer: String,
}

Test plan

• cargo test -p dspy-rs passes
• cargo test -p dsrs-macros passes (including trybuild)
• ADR is readable and accurate