Test flakiness investigation and attempted fixes ❄ #5806

	name: Test Textual module

	on:
	pull_request:
	paths:
	- '.github/workflows/pythonpackage.yml'
	- '**.py'
	- '**.pyi'
	- '**.css'
	- '**.ambr'
	- '**.lock'
	- 'Makefile'

	jobs:
	build:
	runs-on: ${{ matrix.os }}
	strategy:
	matrix:
	os: [ubuntu-latest, macos-latest, windows-latest]
	python-version: ["3.7", "3.8", "3.9", "3.10", "3.11", "3.12"]
	defaults:
	run:
	shell: bash
	steps:
	- uses: actions/[email protected]
	- name: Install and configure Poetry # This could be cached, too...
	uses: snok/[email protected]
	with:
	version: 1.4.2
	virtualenvs-in-project: true
	- name: Set up Python ${{ matrix.python-version }}
	uses: actions/[email protected]
	with:
	python-version: ${{ matrix.python-version }}
	architecture: x64
	allow-prereleases: true
	- name: Load cached venv
	id: cached-poetry-dependencies
	uses: actions/cache@v3
	with:
	path: .venv
	key: venv-${{ runner.os }}-${{ matrix.python-version }}-${{ hashFiles('**/poetry.lock') }}
	- name: Install dependencies
	run: poetry install --extras syntax
	if: steps.cached-poetry-dependencies.outputs.cache-hit != 'true'
	# - name: Typecheck with mypy
	# run: \|
	# make typecheck
	- name: Test with pytest
	run: \|
	source $VENV
	pytest tests -v --cov=./src/textual --cov-report=xml:./coverage.xml --cov-report term-missing
	- name: Upload snapshot report
	if: always()
	uses: actions/upload-artifact@v3
	with:
	name: snapshot-report-textual
	path: snapshot_report.html

Provide feedback