feat: add assert_stderr and assert_stderr_line

[adoyle-h]

fix #42

[adoyle-h]

@martin-schulze-vireso This PR is ready. Can you review it?

[martin-schulze-vireso]

I really dislike the amount of code duplication. Can we have a central implementation that is used by both assert_output and assert_stderr (and _lines likewise)? Similarly, I'd fold the documentation into assert_output's or link to it from there. Feature changes will sooner or later get lost on one of the two duplicates.

[martin-schulze-vireso]

@adoyle-h Do you plan to work on this?

[adoyle-h]

Sorry, I'm occupied with work.

[nicola-lunghi]

Hi @martin-schulze-vireso
just stumbled on this
can we reopen this so we can fix it?

[martin-schulze-vireso]

If you are willing to work in this, you can use the code as starting point but have to open your own PR.

I don't have the time to do so myself right now.

[nicola-lunghi]

If you are willing to work in this, you can use the code as starting point but have to open your own PR.

I don't have the time to do so myself right now.

Hi @martin-schulze-vireso started working on this
what about a --stderr option in assert_output?

assert_output --stderr "My stderr out"

I think this wil allows to reuse most of assert_output in

bats-assert/src/assert_output.bash

Lines 124 to 197 in e2d855b

	assert_output() {
	local -i is_mode_partial=0
	local -i is_mode_regexp=0
	local -i is_mode_nonempty=0
	local -i use_stdin=0
	: "${output?}"
	# Handle options.
	if (( $# == 0 )); then
	is_mode_nonempty=1
	fi
	while (( $# > 0 )); do
	case "$1" in
	-p|--partial) is_mode_partial=1; shift ;;
	-e|--regexp) is_mode_regexp=1; shift ;;
	-|--stdin) use_stdin=1; shift ;;
	--) shift; break ;;
	*) break ;;
	esac
	done
	if (( is_mode_partial )) && (( is_mode_regexp )); then
	echo "\`--partial' and \`--regexp' are mutually exclusive" \
	| batslib_decorate 'ERROR: assert_output' \
	| fail
	return $?
	fi
	# Arguments.
	local expected
	if (( use_stdin )); then
	expected="$(cat -)"
	else
	expected="${1-}"
	fi
	# Matching.
	if (( is_mode_nonempty )); then
	if [ -z "$output" ]; then
	echo 'expected non-empty output, but output was empty' \
	| batslib_decorate 'no output' \
	| fail
	fi
	elif (( is_mode_regexp )); then
	if [[ '' =~ $expected ]] || (( $? == 2 )); then
	echo "Invalid extended regular expression: \`$expected'" \
	| batslib_decorate 'ERROR: assert_output' \
	| fail
	elif ! [[ $output =~ $expected ]]; then
	batslib_print_kv_single_or_multi 6 \
	'regexp' "$expected" \
	'output' "$output" \
	| batslib_decorate 'regular expression does not match output' \
	| fail
	fi
	elif (( is_mode_partial )); then
	if [[ $output != *"$expected"* ]]; then
	batslib_print_kv_single_or_multi 9 \
	'substring' "$expected" \
	'output' "$output" \
	| batslib_decorate 'output does not contain substring' \
	| fail
	fi
	else
	if [[ $output != "$expected" ]]; then
	batslib_print_kv_single_or_multi 8 \
	'expected' "$expected" \
	'actual' "$output" \
	| batslib_decorate 'output differs' \
	| fail
	fi
	fi
	}

also we can define an "alias" for assert_stderr => assert_output --stderr

[nicola-lunghi]

see #69