CI: Add poetry caching from libvcs, add python 2.7

.github/workflows/tests.yml

@@ -4,15 +4,59 @@ on: [push, pull_request]
 
 jobs:
   build:
+    # Don't run twice for internal PRs from our own repo
+    if: github.event_name == 'push' || github.event.pull_request.head.repo.full_name != github.repository
 
     runs-on: ubuntu-latest
     strategy:
       matrix:
-        python-version: [ '3.x' ]
+        python-version: [ '2.7', '3.x' ]
         tmux-version: [ '2.6', '2.7', '2.8', '3.0', 'master' ]
     steps:
     - uses: actions/checkout@v1
-    - name: Cache tmux build ${{ matrix.tmux-version }}
+
+    - name: Set up Python ${{ matrix.python-version }}
+      uses: actions/setup-python@v1
+      with:
+        python-version: ${{ matrix.python-version }}
+
+    - name: Get full Python version
+      id: full-python-version
+      shell: bash
+      run: echo ::set-output name=version::$(python -c "import sys; print('-'.join(str(v) for v in sys.version_info))")
+
+    - name: Install poetry
+      run: |
+        curl -O -sSL https://raw.githubusercontent.com/sdispater/poetry/master/get-poetry.py
+        python get-poetry.py -y
+        echo "::set-env name=PATH::$HOME/.poetry/bin:$PATH"
+        rm get-poetry.py
+
+    - name: Get poetry cache paths from config
+      run: |
+        echo ::set-env name=poetry_cache_dir::$(poetry config --list | sed -n 's/.*cache-dir = //p' | sed -e 's/^"//' -e 's/"$//')
+        echo ::set-env name=poetry_virtualenvs_path::$(poetry config --list | sed -n 's/.*virtualenvs.path = .* # //p' | sed -e 's/^"//' -e 's/"$//')
+
+    - name: Configure poetry
+      shell: bash
+      run: poetry config virtualenvs.in-project true
+
+    - name: Set up poetry cache
+      uses: actions/cache@v2
+      id: cache
+      with:
+        path: |
+          .venv
+          {{ env.poetry_cache_dir }}
+          {{ env.poetry_virtualenvs_path }}
+        key: venv-${{ runner.os }}-${{ steps.full-python-version.outputs.version }}-${{ hashFiles('**/poetry.lock') }}
+
+    - name: Ensure cache is healthy
+      if: steps.cache.outputs.cache-hit == 'true'
+      shell: bash
+      run: poetry run pip --version >/dev/null 2>&1 || rm -rf .venv
+
+    - name: Setup tmux build cache for tmux ${{ matrix.tmux-version }}
       id: tmux-build-cache
       uses: actions/cache@v1
       with:
@@ -33,18 +77,14 @@ jobs:
         export PATH=$HOME/tmux-builds/tmux-${{ matrix.tmux-version }}/bin:$PATH
         cd ~
         tmux -V
-    - name: Configure git
-      run: |
-        git config --global user.name 'travis-ci'
-        git config --global user.email 'travis@nowhere.edu'
-    - name: Set up Python ${{ matrix.python-version }}
-      uses: actions/setup-python@v1
-      with:
-        python-version: ${{ matrix.python-version }}
+
+    - name: Upgrade pip
+      shell: bash
+      run: poetry run python -m pip install pip -U
+
     - name: Install python dependencies
       run: |
-        python -m pip install --upgrade poetry
-        poetry install
+        poetry install -E "test coverage lint"
     - name: Lint with flake8
       run: |
         poetry run flake8