Implement unit tests for utilities, events, and TAP bridge (19 files)

[Koan-Bot]

Context

Across t/unit/Test2/Harness/, t/unit/Test2/Tools/, t/unit/Test2/EventFacet/, and t/unit/TAP/ there are 19 test stubs with skip_all "write me" placeholders. These cover utility functions, event handling, log processing, file I/O abstractions, and the TAP compatibility bridge.

Modules to test

Utilities (8 files):

• Util.t → Test2::Harness::Util (core utility functions)
• Util/Deprecated.t, Util/File.t, Util/File/JSON.t, Util/File/JSONL.t, Util/File/Stream.t, Util/File/Value.t, Util/HashBase.t

Log processing (4 files):

• Log.t → Test2::Harness::Log
• Log/CoverageAggregator.t, Log/CoverageAggregator/ByRun.t, Log/CoverageAggregator/ByTest.t
• Log/TimeTracker.t → Test2::Harness::Log::TimeTracker
• Util/LogFile.t → Test2::Harness::Util::LogFile

Events (1 file):

• Event.t → Test2::Harness::Event
• Test2/EventFacet/Binary.t → Test2::EventFacet::Binary

TAP bridge (2 files):

• TAP/Harness/Yath.t → TAP::Harness::Yath
• TAP/Harness/Yath/Aggregator.t → TAP::Harness::Yath::Aggregator

Test tools (1 file):

• Test2/Tools/HarnessTester.t → Test2::Tools::HarnessTester

Suggested test scenarios

Utility functions (Test2::Harness::Util)

• clean_path() — path normalization, absolute path handling
• find_in_updir() — upward directory search
• is_same_file() — inode comparison
• mod2file() / file2mod() — module ↔ file path conversion
• fqmod() — fully-qualified module name resolution
• parse_exit() — exit code interpretation (signal, core dump, status)
• open_file() / read_file() / write_file() / write_file_atomic() — file I/O
• lock_file() / unlock_file() — file locking
• sanitize_filename() — ANSI stripping, control char escaping

File abstractions

• File::JSON: JSON file read/write with atomic operations
• File::JSONL: line-delimited JSON (log files), append, iterate
• File::Stream: streaming file reader
• File::Value: single-value file (PID files, status files)

Log processing

• Log: JSONL log format documentation validation
• CoverageAggregator: coverage data aggregation (ByRun vs ByTest strategies)
• TimeTracker: test timing data collection and reporting
• LogFile: log file reading, event iteration

Events

• Event: as_json() serialization, trace() accessor, facet_data structure
• EventFacet::Binary: binary data facet handling

TAP bridge

• TAP::Harness::Yath: TAP::Harness compatibility wrapper — runtests() method
• Aggregator: TAP result aggregation

Test tools

• HarnessTester: test helpers for harness testing — event generation, assertion utilities

Notes

Many of these are excellent good first issue candidates, especially the utility functions and file abstractions — self-contained, well-defined input/output, no complex setup needed.

Test2::Harness::Util already has known edge cases documented:

• @INC can contain blessed objects and code refs (must filter for JSON encoding)
• sanitize_filename() must handle ANSI CSI/OSC sequences

[atoomic]

@Koan-Bot fix