From: Jonathan Nieder <jrnieder@gmail.com>
Date: Tue, 04 Aug 2020 17:02:20 GMT
Subject: Re: [PATCH v2 01/18] maintenance: create basic maintenance runner
Message-ID: <20200804170220.GB227292@google.com>
In-Reply-To: <2b6da345-d004-1d83-78cd-3f1ceaf278d9@gmail.com>

Derrick Stolee wrote:

> Here is my attempt so far:
[...]
> 	test_subcommand_called "gc" run-no-auto.txt &&
> 	test_subcommand_not_called "gc --auto" run-auto.txt &&
> 	test_subcommand_called "gc --quiet" run-quiet.txt

I like it.  Some tweaks:
- can simplify by using 'printf' instead of sed
- passing the trace in stdin
- following the convention that helpers like test_i18ngrep use of
  accepting ! as a parameter to negate the exit code

That would make (untested)

# Check that the given command was invoked as part of the
# trace2-format trace on stdin.
#
#	test_subcommand_called [!] <command> <args>... < <trace>
#
# For example, to look for an invocation of "git upload-pack
# /path/to/repo"
#
#	GIT_TRACE2_EVENT=event.log git fetch ... &&
#	test_subcommand_called git upload-pack "$PATH" <event.log
#
# If the first parameter passed is !, this instead checks that
# the given command was not called.
#
test_subcommand_called () {
	local negate=
	if test "$1" = "!"
	then
		negate=t
		shift
	fi

	local expr=$(printf '"%s",' "$@")
	expr="${expr%,}"

	if test -n "$negate"
	then
		! grep "\[$expr\]"
	else
		grep "\[$expr\]"
	fi
}