alknet/tasks/typedef/tests.md

id, name, status, depends_on, scope, risk, impact, level

id	name	status	depends_on	scope	risk	impact	level
typedef/tests	Write comprehensive tests for alknet-typedef: unit tests, integration tests, and POC round-trip tests	pending	typedef/engine	moderate	low	component	implementation

Description

Write comprehensive tests for the alknet-typedef crate. Tests should cover all 17 TypeDef:* kinds, both layout modes, endianness, TUnion dispatch, validation, and error paths. Include the POC-verified round-trip tests that validate byte-identical output against known-good serialization.

Test categories

1. Schema layer tests (tests/schema_tests.rs or #[cfg(test)] mod tests in schema.rs)

• get_typedef_kind() correctly identifies all 17 kinds
• type_size() returns correct sizes for all fixed-size types
• type_size() returns None for variable-length types
• natural_alignment() returns correct alignment
• Endian::from_schema() defaults to Little, parses "big" correctly
• parse_encoding() handles true, { "encoding": "length-prefixed" }, { "encoding": "offset-indirect" }
• parse_align() returns None when absent, correct value when present
• parse_max_length() returns None when absent, correct value when present
• parse_discriminator() handles byte-offset and field-name discriminators
• normalize_refs() rewrites bare-name refs, leaves full paths unchanged, handles nested objects

2. Data access tests (tests/data_access_tests.rs)

• Fixed-size read/write round-trip for all types: i8, i16, i32, u8, u16, u32, u64, f32, f64, bool, enum
• Endianness: little-endian and big-endian produce correct byte order
• read_bool: 0x00 → false, 0x01 → true, other values → error
• read_string: correct length-prefixed read, UTF-8 validation, buffer-too-short error
• read_bytes: correct length-prefixed read, buffer-too-short error
• write_string / write_bytes: correct length prefix + data written, returns bytes written
• read_string_indirect / read_bytes_indirect: correct offset-indirect read
• Buffer bounds checking: all functions return TypedefError::Access for too-short buffers
• Field path in error messages is correct

3. OffsetMap tests (aligned static mode) (tests/offset_map_tests.rs)

• Simple struct: { u8, u32, f32 } → correct offsets with natural alignment (0, 4, 8)
• Nested struct: { header: { version: u32, magic: u32 }, payload: bytes } → correct dotted paths
• TArray of fixed-size elements: correct stride and element offsets
• TArray with fixed count (minItems == maxItems): correct total size
• TArray with variable count: length-prefixed encoding
• Variable-length types (inline length-prefixing): 4-byte length prefix at known offset
• Variable-length types (maxLength): reserved bytes at fixed offset
• Variable-length types (offset-indirect): 8-byte {offset, length} struct
• TUnion with byte-offset discriminator: discriminator at offset, variant at offset + disc_size
• TUnion with field-name discriminator: discriminator is a regular field
• Struct-level "align" annotation: rounds up total size
• Field-level "align" annotation: overrides struct default
• OffsetMap::get() returns correct ByteRange for dotted paths
• OffsetMap::total_size() is correct
• OffsetMap::iter() returns all fields

4. LayoutBuilder tests (packed sequential mode, write-side) (tests/layout_builder_tests.rs)

• Simple struct: { u8, u32, string } → packed offsets (0, 1, 5) with no padding
• Variable-length fields shift subsequent fields based on actual sizes
• Nested struct: correct dotted paths with packed offsets
• TArray of fixed-size elements: correct stride (element size, no padding)
• TUnion with byte-offset discriminator: correct discriminator and variant positions
• Missing variable-length field size → TypedefError::Offset

5. SequentialReader tests (packed sequential mode, read-side) (tests/sequential_reader_tests.rs)

• Read fields sequentially: correct values and position advancement
• Variable-length fields: reads length prefix, skips data, advances correctly
• read_next() returns None when all fields read
• read_field() walks through preceding fields
• reset() resets position
• Nested struct: returns FieldValue::Struct { start, end }
• TUnion: returns FieldValue::Union { ... }
• TArray: returns FieldValue::Array { count, element_start, element_stride }
• Endianness respected for multi-byte reads

6. TUnion dispatch tests (tests/tunion_tests.rs)

• Byte-offset discriminator: reads u8 at offset 0, returns correct key and variant offset
• Byte-offset discriminator with u16 and u32 types
• Field-name discriminator: reads string field, returns correct key
• Field-name discriminator with u8 and enum field types
• resolve_variant(): resolves $ref pointers, returns error for unknown keys
• discriminator_size(): correct for each discriminator type

7. Validation tests (tests/validation_tests.rs)

• build_validator() returns a working validator
• Each TypeDef:* kind's validator rejects invalid values
• Float32Validator: rejects NaN, Infinity
• Int8Validator: rejects 128, -129
• Uint8Validator: rejects -1, 256
• StringValidator: rejects non-string, respects maxLength
• TimestampValidator: rejects non-RFC 3339 strings
• StructValidator: validates nested fields
• UnionValidator: validates discriminator membership
• ArrayValidator: validates element types and length bounds

8. TypedefEngine integration tests (tests/engine_tests.rs)

• compile() in aligned mode produces a working engine
• compile() in packed mode produces a working engine
• compile() normalizes $ref values
• compile() returns error for invalid schemas
• endian() and mode() accessors
• offset_map(), layout_builder(), sequential_reader() accessors
• validate_json() and is_valid_json() work correctly
• read_field() and write_field() in aligned mode

9. POC round-trip tests (tests/poc_roundtrip_tests.rs)

Replicate the key POC tests from /workspace/alknet-typedef-poc/:

• Fixed-size round-trip: Write u8, u16, u32, u64, f32, f64, bool, enum to a buffer at computed offsets; read back; verify values match.
• String round-trip: Write a length-prefixed string; read back; verify.
• Nested struct round-trip: Write a struct with nested fields; read back; verify.
• Endianness round-trip: Write in big-endian; read back in big-endian; verify.
• SFTP packet round-trip (if SFTP schemas are available): Write an SFTP Read/Write/Status packet; verify byte-identical output against known-good serialization.

10. Error path tests

• Buffer too short for every read function
• Invalid UTF-8 in read_string
• Invalid boolean byte value
• Missing required schema keywords
• Unknown TypeDef:* kind
• Malformed discriminator annotation
• Unknown discriminator value
• Missing variable-length field size in LayoutBuilder::build()

Test organization

Tests can be organized as:

• Unit tests in #[cfg(test)] mod tests blocks within each source file (for module-internal functions).
• Integration tests in tests/ directory (for public API tests that exercise multiple modules).

What this does NOT include

• Tests for arrays of variable-length-element structs (deferred, OQ-069)
• WASM-specific tests (deferred, OQ-070)
• Performance benchmarks

Acceptance Criteria

• Schema layer tests: all schema.rs public functions tested
• Data access tests: all read/write functions tested with round-trip, endianness, and error paths
• OffsetMap tests: aligned static layout with alignment, nesting, arrays, unions, variable-length types
• LayoutBuilder tests: packed sequential layout with variable-length shifting
• SequentialReader tests: sequential field reading with position tracking
• TUnion tests: both discriminator kinds, variant resolution
• Validation tests: all 17 custom keyword validators tested
• Engine tests: compile, accessors, convenience methods
• POC round-trip tests: fixed-size, string, nested struct, endianness
• Error path tests: buffer-too-short, invalid UTF-8, malformed schemas
• All tests pass: cargo test -p alknet-typedef
• No unwrap() in test code that would mask failures (use ? or assert!(matches!(...)))
• cargo clippy -p alknet-typedef --all-targets succeeds with no warnings
• cargo build --workspace still succeeds
• cargo test --workspace still succeeds (old tests untouched)

References

• docs/research/alknet-typedef/findings.md — POC results (26 tests passing)
• /workspace/alknet-typedef-poc/src/lib.rs — POC test reference
• docs/architecture/crates/typedef/README.md — design principles
• All preceding task files in tasks/typedef/

Notes

This is the testing task — it validates the entire crate. The POC had 26 tests passing; this task should cover at least that many scenarios plus additional error-path tests. Tests should be organized by module/concern. The SFTP round-trip test is a stretch goal — it requires SFTP packet schemas which may not be in the repo yet. If SFTP schemas aren't available, test with hand-crafted schemas that exercise the same patterns (byte-offset TUnion, big-endian, mixed fixed/variable fields).

Summary

To be filled on completion