Re: [PATCH v7 2/2] json-writer: t0019: add Python unit test

> > Probably. We may want to go the same route as we did for perl in 
> > a0e0ec9f7d (t: provide a perl() function which uses $PERL_PATH,
> > 2013-10-28) so that test writers don't have to remember this.
> > 
> > That said, I wonder if it would be hard to simply do the python bits
> > here in perl. This is the first use of python in our test scripts (and
> 
> Hmm, not quite the _first_ use:
> 
> $ git grep PYTHON_PATH -- t
> t/lib-git-p4.sh:        (cd / && "$PYTHON_PATH" -c 'import time; print(int(time.time()))')
> t/lib-git-p4.sh:        "$PYTHON_PATH" "$TRASH_DIRECTORY/marshal-dump.py"
> t/t9020-remote-svn.sh:export PATH PYTHON_PATH GIT_BUILD_DIR
> t/t9020-remote-svn.sh:exec "$PYTHON_PATH" "$GIT_BUILD_DIR/contrib/svn-fe/svnrdump_sim.py" "$@"
> t/t9802-git-p4-filetype.sh:             "$PYTHON_PATH" "$TRASH_DIRECTORY/k_smush.py" <"$cli/k-text-k" >cli-k-text-k-smush &&
> t/t9802-git-p4-filetype.sh:             "$PYTHON_PATH" "$TRASH_DIRECTORY/ko_smush.py" <"$cli/k-text-ko" >cli-k-text-ko-smush &&
> t/t9802-git-p4-filetype.sh:             "$PYTHON_PATH" "$TRASH_DIRECTORY/gendouble.py" >%double.png &&
> t/t9810-git-p4-rcs.sh:  "$PYTHON_PATH" "$TRASH_DIRECTORY/scrub_k.py" <"$git/$file" >"$scrub" &&
> t/t9810-git-p4-rcs.sh:  "$PYTHON_PATH" "$TRASH_DIRECTORY/scrub_ko.py" <"$git/$file" >"$scrub" &&
> $