Implement LCOV format reporting - #70
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Implements generating coverage reporting in LCOV format, controlled by the flag `--lcov`. Changes: - Added lcovreport.py module with LcovReporter class for generating LCOV format output - Integrated LCOV reporting into slipcover.py with print_lcov() function - Added --lcov command-line flag to __main__.py for selecting LCOV output - Added --lcov-test-name and --lcov-comment, common in other LCOV tools - Exported print_lcov in __init__.py to make it accessible - Added tests for LCOV reporting (with and without branches) The LCOV format includes: - TN: Test name (optional) - SF: Source file path - BRDA: Branch coverage data (when --branch is used) - BRF/BRH: Branch statistics - DA: Line coverage data - LF/LH: Line statistics - end_of_record marker Usage examples: python -m slipcover --lcov --out coverage.lcov script.py python -m slipcover --branch --lcov --out coverage.lcov script.py
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Pull request overview
This PR implements LCOV format coverage reporting for slipcover, enabling output compatible with tools that consume LCOV format. The implementation adds a new LcovReporter class and integrates it into the CLI with --lcov flag support, along with optional test name and comment features.
Changes:
- Added LCOV format reporting with line and branch coverage support
- Integrated LCOV output option into CLI with
--lcov,--lcov-test-name, and--lcov-commentflags - Added comprehensive test coverage for LCOV functionality including branches, test names, and comments
Reviewed changes
Copilot reviewed 5 out of 5 changed files in this pull request and generated 5 comments.
Show a summary per file
| File | Description |
|---|---|
| src/slipcover/lcovreport.py | New module implementing LCOV format reporter with line and branch coverage |
| src/slipcover/slipcover.py | Added print_lcov() function to expose LCOV reporting API |
| src/slipcover/main.py | Integrated LCOV CLI flags and output handling in both merge and normal execution modes |
| src/slipcover/init.py | Exported print_lcov in public API |
| tests/test_coverage.py | Added test suite for LCOV reporting covering various scenarios |
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@emeryberger addressed Copilot's findings and merged updated main. ptal! Thanks! |
…d tests SF: entries used the raw coverage-dict key, which on Windows contains backslashes (PathSimplifier renders WindowsPath natively) -- normalize to '/' as xmlreport.py already does, for genhtml/lcov tooling compatibility. get_branch_info() took a missing_arcs parameter (built by get_missing_branch_arcs()) that it never used -- it recomputed is_taken independently via an O(n) list-membership check per branch. Replaced with a proper O(1) set lookup instead of just deleting the dead code, normalizing branch tuples first since --merge round-trips coverage data through JSON, which deserializes branch arcs as unhashable lists rather than tuples. Added tests for: Windows path normalization, empty/100%/0% coverage files, --merge --lcov (previously untested, and the JSON round-trip issue above only surfaces through this path), and a test asserting exact per-branch BRDA taken/not-taken values -- the existing branch test only checks aggregate BRF/BRH counts, which stay identical even if taken/not-taken were fully inverted, since this fixture happens to have a symmetric 2-taken/2-missing split. Co-Authored-By: Claude Sonnet 5 <noreply@anthropic.com>
Backslashes inside an f-string expression part (`{...}`) are only
allowed since Python 3.12 (PEP 701); on 3.9-3.11 this was a hard
SyntaxError at import time, breaking every job in that range in CI.
Move the .replace() call to a separate statement before the f-string.
Co-Authored-By: Claude Sonnet 5 <noreply@anthropic.com>
An empty module compiles to a single line-1 entry on Python 3.9/3.10 (findlinestarts -> (0, 1)) but to (0, 0) on 3.11+, which slipcover's own line-collection already filters out as non-real. So an empty .py file legitimately has 1 trivially-executed line on 3.9/3.10 and 0 on 3.11+ -- both correct, and not something to "fix" in slipcover itself. The test's hardcoded LF:0/LH:0 assumption only held on 3.11+. Assert the actual invariant instead: no DA: line reports a zero hit count, i.e. nothing is missing, regardless of the exact (version-dependent) line count. Co-Authored-By: Claude Sonnet 5 <noreply@anthropic.com>
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Implements generating coverage reporting in LCOV format, controlled by the flag
--lcov.Changes:
lcovreport.pymodule withLcovReporterclass for generating LCOV format outputslipcover.pywithprint_lcov()function--lcovcommand-line flag to__main__.pyfor selecting LCOV output--lcov-test-nameand--lcov-comment, common in other LCOV toolsThe LCOV format includes:
Usage examples:
No specific issue is tracking this, but LCOV is a widely-used report format for tooling like
genhtml, Coveralls, and Codecov (see #30, a closed issue asking generally about Codecov compatibility) -- flagging in case it's relevant to anyone following those threads.