Add (invalid) test cases of proportions == 0.0 #189

	name: Run tests

	on:
	pull_request:
	push:
	branches: [main]

	jobs:
	tests:
	runs-on: ${{ matrix.os }}
	defaults:
	run:
	shell: bash
	strategy:
	fail-fast: false
	matrix:
	os: [ubuntu-24.04, windows-2022, macos-14]
	steps:
	- uses: actions/checkout@v2
	- uses: actions/setup-python@v2
	with:
	python-version: 3.12
	- name: Install dependencies
	run: \|
	python -m pip install --upgrade pip
	python -m pip install -r requirements_CI.txt
	- name: Tests for reference implementation
	run: \|
	cd reference_implementation
	# Require 100% test coverage for reference implementation.
	python -m pytest \
	--cov=demes_parser \
	--cov-report=term-missing \
	--cov-fail-under=100 \
	tests.py
	- name: Tests for schema
	run: \|
	python -m pytest tests.py

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