Build CoolProp so we can test on Python 3.8

CoolProp 6.3.0 from PyPI raises a TypeError due to some changes that
since the release of Python 3.8. The master branch of CoolProp has
the fixes, so build that and test ThermoState on Python 3.8.

Don't do this on Windows, since Windows should be covered by the
other Python versions, and I can't easily test compiling CoolProp
on Windows right now.

.github/workflows/pythonpackage.yml

@@ -18,7 +18,7 @@ jobs:
     runs-on: ${{ matrix.os }}
     strategy:
       matrix:
-        python-version: [3.6, 3.7, 3.8]
+        python-version: [3.6, 3.7]
         os: [ubuntu-latest, macos-latest, windows-latest]
       fail-fast: false
 
@@ -41,11 +41,62 @@ jobs:
         token: ${{ secrets.CODECOV_TOKEN }}
         file: ./coverage.xml
 
+  # CoolProp has to be built from the master branch for Python 3.8
+  build-py38:
+    runs-on: ${{ matrix.os }}
+    strategy:
+      matrix:
+        # Don't want to figure out compiling CoolProp on Windows for tests.
+        # These OS should be good enough
+        os: [ubuntu-latest, macos-latest]
+      fail-fast: false
+    steps:
+      - name: Check out the repository
+        uses: actions/checkout@v2
+        with:
+          path: main
+      - name: Set up Python 3.8
+        uses: actions/setup-python@v1
+        with:
+          python-version: 3.8
+      - name: Clone CoolProp
+        uses: actions/checkout@v2
+        with:
+          repository: CoolProp/CoolProp
+          path: CoolProp
+          submodules: 'recursive'
+      - name: Install CoolProp dependencies
+        run: |
+          python -m pip install --upgrade pip setuptools
+          python -m pip install cython wheel
+      - name: Build CoolProp wheel
+        env:
+          MACOSX_DEPLOYMENT_TARGET: 10.13
+        run: |
+          pushd CoolProp/wrappers/Python
+          python ../../dev/generate_headers.py
+          python setup.py bdist_wheel
+          popd
+      - name: Install test dependencies
+        run: |
+          python -m pip install tox tox-venv
+      - name: Test with tox
+        env:
+          CP_PACKAGE_DIST_DIR: ${{ github.workspace }}/CoolProp/wrappers/Python/dist
+        run: |
+          pushd main
+          tox -v -e py38
+      - name: Upload coverage to Codecov
+        uses: codecov/codecov-action@v1
+        with:
+          token: ${{ secrets.CODECOV_TOKEN }}
+          file: main/coverage.xml
+
   notebooks:
     runs-on: ubuntu-latest
     steps:
     - name: Check out the repository
-    uses: actions/checkout@v2
+      uses: actions/checkout@v2
     - name: Set up Python 3.7
       uses: actions/setup-python@v1
       with:

tox.ini

@@ -11,7 +11,6 @@ requires = tox-venv
 python =
     3.6: py36
     3.7: py37
-    3.8: py38
 
 [testenv]
 description = run the tests with pytest under {basepython}
@@ -25,6 +24,9 @@ download = true
 
 [testenv:py38]
 description = run the tests with pytest under {basepython}, allowing failures due to CoolProp
+install_command=python -m pip install --find-links={env:CP_PACKAGE_DIST_DIR:} {opts} {packages}
+pip_pre = true
+
 [testenv:notebooks]
 description = run the Notebooks in the docs folder
 deps =