tests/test-dispatch

cmdutil: changeset_printer: use methods of filectx/changectx.

This allows extensions that modify changeset metadata (e.g.
description) by overriding methods of changectx to get consistent
behavior from all log-like commands, regardless of whether templates
or styles are used. Without this, overriding changectx methods works
if you use styles or templates, but not with default log format.

This meant adding filectx.extra() for consistency with changectx.

#!/bin/sh
# test command parsing and dispatch

"$TESTDIR/hghave" no-outer-repo || exit 80

hg init a
cd a
echo a > a
hg ci -Ama

echo "# missing arg"
hg cat

echo '% [defaults]'
hg cat a
cat >> $HGRCPATH <<EOF
[defaults]
cat = -r null
EOF
hg cat a

echo '% no repo'
cd ..
hg cat

exit 0