qemu/scripts/coverage/compare_gcov_json.py
Alex Bennée 899c3fc2dc scripts/coverage: initial coverage comparison script
This is a very rough and ready first pass at comparing gcovr's json
output between two different runs. At the moment it will give you a
file level diff between two runs but hopefully it wont be too hard to
extend to give better insight.

After generating the coverage results you run with something like:

  ./scripts/coverage/compare_gcov_json.py \
    -a ./builds/gcov.config1/coverage.json \
    -b ./builds/gcov.config2/coverage.json

My hope is we can use this to remove some redundancy from testing as
well as evaluate if new tests are actually providing additional
coverage or just burning our precious CI time.

Signed-off-by: Alex Bennée <alex.bennee@linaro.org>
Cc: Kautuk Consul <kconsul@linux.vnet.ibm.com>
Acked-by: Thomas Huth <thuth@redhat.com>
Message-Id: <20230403134920.2132362-2-alex.bennee@linaro.org>
2023-04-04 15:16:29 +01:00

120 lines
3.5 KiB
Python
Executable File

#!/usr/bin/env python3
#
# Compare output of two gcovr JSON reports and report differences. To
# generate the required output first:
# - create two build dirs with --enable-gcov
# - run set of tests in each
# - run make coverage-html in each
# - run gcovr --json --exclude-unreachable-branches \
# --print-summary -o coverage.json --root ../../ . *.p
#
# Author: Alex Bennée <alex.bennee@linaro.org>
#
# SPDX-License-Identifier: GPL-2.0-or-later
#
import argparse
import json
import sys
from pathlib import Path
def create_parser():
parser = argparse.ArgumentParser(
prog='compare_gcov_json',
description='analyse the differences in coverage between two runs')
parser.add_argument('-a', type=Path, default=None,
help=('First file to check'))
parser.add_argument('-b', type=Path, default=None,
help=('Second file to check'))
parser.add_argument('--verbose', action='store_true', default=False,
help=('A minimal verbosity level that prints the '
'overall result of the check/wait'))
return parser
# See https://gcovr.com/en/stable/output/json.html#json-format-reference
def load_json(json_file_path: Path, verbose = False) -> dict[str, set[int]]:
with open(json_file_path) as f:
data = json.load(f)
root_dir = json_file_path.absolute().parent
covered_lines = dict()
for filecov in data["files"]:
file_path = Path(filecov["file"])
# account for generated files - map into src tree
resolved_path = Path(file_path).absolute()
if resolved_path.is_relative_to(root_dir):
file_path = resolved_path.relative_to(root_dir)
# print(f"remapped {resolved_path} to {file_path}")
lines = filecov["lines"]
executed_lines = set(
linecov["line_number"]
for linecov in filecov["lines"]
if linecov["count"] != 0 and not linecov["gcovr/noncode"]
)
# if this file has any coverage add it to the system
if len(executed_lines) > 0:
if verbose:
print(f"file {file_path} {len(executed_lines)}/{len(lines)}")
covered_lines[str(file_path)] = executed_lines
return covered_lines
def find_missing_files(first, second):
"""
Return a list of files not covered in the second set
"""
missing_files = []
for f in sorted(first):
file_a = first[f]
try:
file_b = second[f]
except KeyError:
missing_files.append(f)
return missing_files
def main():
"""
Script entry point
"""
parser = create_parser()
args = parser.parse_args()
if not args.a or not args.b:
print("We need two files to compare")
sys.exit(1)
first_coverage = load_json(args.a, args.verbose)
second_coverage = load_json(args.b, args.verbose)
first_missing = find_missing_files(first_coverage,
second_coverage)
second_missing = find_missing_files(second_coverage,
first_coverage)
a_name = args.a.parent.name
b_name = args.b.parent.name
print(f"{b_name} missing coverage in {len(first_missing)} files")
for f in first_missing:
print(f" {f}")
print(f"{a_name} missing coverage in {len(second_missing)} files")
for f in second_missing:
print(f" {f}")
if __name__ == '__main__':
main()