tests/test-diffstat

diff: add --stat for diffstat output

diff/qdiff --stat invokes patch.diffstat() on the diff output.

When in interactive mode, the output's maximum width is determined by the
terminal's width.

#!/bin/sh

hg init repo
cd repo
i=0; while (( $i < 213 )); do echo a >> a; i=$(($i + 1)); done
hg add a

echo '% wide diffstat'
hg diff --stat

echo '% diffstat width'
COLUMNS=24 hg diff --config ui.interactive=true --stat

hg ci -m adda

cat >> a <<EOF
a
a
a
EOF

echo '% narrow diffstat'
hg diff --stat

hg ci -m appenda

printf '%b' '\x00' > b
hg add b

echo '% binary diffstat'
hg diff --stat