From: Derrick Stolee <dstolee@xxxxxxxxxxxxx>
We have coverage targets in our Makefile for using gcov to display line
coverage based on our test suite. The way I like to do it is to run:
make coverage-test
make coverage-report
This leaves the repo in a state where every X.c file that was covered has
an X.c.gcov file containing the coverage counts for every line, and "#####"
at every uncovered line.
There have been a few bugs in recent patches what would have been caught
if the test suite covered those blocks (including a few of mine). I want
to work towards a "sensible" amount of coverage on new topics. In my opinion,
this means that any logic should be covered, but the 'die()' blocks covering
very unlikely (or near-impossible) situations may not warrant coverage.
It is important to not measure the coverage of the codebase by what old code
is not covered. To help, I created the 'contrib/coverage-diff.sh' script.
After creating the coverage statistics at a version (say, 'topic') you can
then run
contrib/coverage-diff.sh base topic
to see the lines added between 'base' and 'topic' that are not covered by the
test suite. The output uses 'git blame -c' format so you can find the commits
responsible and view the line numbers for quick access to the context.
Helped-by: Junio C Hamano <gister@xxxxxxxxx>
Signed-off-by: Derrick Stolee <dstolee@xxxxxxxxxxxxx>
---
contrib/coverage-diff.sh | 79 ++++++++++++++++++++++++++++++++++++++++
1 file changed, 79 insertions(+)
create mode 100755 contrib/coverage-diff.sh
diff --git a/contrib/coverage-diff.sh b/contrib/coverage-diff.sh
new file mode 100755
index 0000000000..48b9a3ae96
--- /dev/null
+++ b/contrib/coverage-diff.sh
@@ -0,0 +1,79 @@
+#!/bin/sh
+
+# Usage: Run 'contrib/coverage-diff.sh <version1> <version2>' from source-root
+# after running
+#
+# make coverage-test
+# make coverage-report
+#
+# while checked out at <version2>. This script combines the *.gcov files
+# generated by the 'make' commands above with 'git diff <version1> <version2>'
+# to report new lines that are not covered by the test suite.
+
+V1=$1
+V2=$2
+
+diff_lines () {
+ perl -e '
+ my $line_num;
+ while (<>) {
+ # Hunk header? Grab the beginning in postimage.
+ if (/^@@ -\d+(?:,\d+)? \+(\d+)(?:,\d+)? @@/) {
+ $line_num = $1;
+ next;
+ }
+
+ # Have we seen a hunk? Ignore "diff --git" etc.
+ next unless defined $line_num;
+
+ # Deleted line? Ignore.
+ if (/^-/) {
+ next;
+ }
+
+ # Show only the line number of added lines.
+ if (/^\+/) {
+ print "$line_num\n";
+ }
+ # Either common context or added line appear in
+ # the postimage. Count it.
+ $line_num++;
+ }
+ '
+}
+
+files=$(git diff --name-only $V1 $V2 -- *.c)
+
+for file in $files
+do
+ git diff $V1 $V2 -- $file \
+ | diff_lines \
+ | sort >new_lines.txt
+
+ if ! test -s new_lines.txt
+ then
+ continue
+ fi
+
+ hash_file=$(echo $file | sed "s/\//\#/")
+ sed -ne '/#####:/{
+ s/ #####://
+ s/:.*//
+ s/ //g
+ p
+ }' "$hash_file.gcov" \
+ | sort >uncovered_lines.txt
+
+ comm -12 uncovered_lines.txt new_lines.txt \
+ | sed -e 's/$/\)/' \
+ | sed -e 's/^/\t/' \
+ >uncovered_new_lines.txt
+
+ grep -q '[^[:space:]]' < uncovered_new_lines.txt && \
+ echo $file && \
+ git blame -c $file \
+ | grep -f uncovered_new_lines.txt
+
+ rm -f new_lines.txt uncovered_lines.txt uncovered_new_lines.txt
+done
+
--
gitgitgadget
