[ENH] do not add subject to layout if it is empty #666

	---
	name: 'octave: tests'

	on:
	push:
	branches:
	- master
	- dev
	paths:
	- '**.m'
	pull_request:
	branches: ['*']

	env:
	OCTFLAGS: --no-gui --no-window-system --silent

	jobs:
	test:

	runs-on: ubuntu-22.04

	steps:

	- name: Clone bids-matlab
	uses: actions/checkout@v3
	with:
	submodules: true
	fetch-depth: 1

	- name: Install dependencies
	run: \|
	sudo apt-get -y -qq update
	sudo apt-get -y install unzip wget

	- name: Install bids validator
	run: npm install -g bids-validator

	- name: Install bids-example
	run: \|
	cd tests
	make data

	- name: Install Moxunit and MOcov
	run: \|
	git clone https://github.com/MOxUnit/MOxUnit.git --depth 1
	git clone https://github.com/MOcov/MOcov.git --depth 1

	- name: Install octave
	run: \|
	sudo apt-get -y -qq update
	sudo apt-get -y install \
	octave \
	liboctave-dev\
	octave-common \
	octave-io \
	octave-image \
	octave-signal \
	octave-statistics
	make -C MOxUnit install
	make -C MOcov install

	- name: Install JSONio
	run: \|
	git clone https://github.com/gllmflndn/JSONio.git --depth 1
	cd JSONio
	mkoctfile --mex jsonread.c jsmn.c -DJSMN_PARENT_LINKS
	octave $OCTFLAGS --eval "addpath(fullfile(pwd)); savepath();"

	- name: Run unit tests Octave
	run: \|
	octave $OCTFLAGS --eval "success = run_tests(); assert(success);"

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