Moved flake8, shell and documentation tests to Github Action (#17328)

* Move flake8 tests on Github Actions

* Move shell test to Github Actions

* Moved documentation build to Github Action

* Don't run coverage on Python 2.6

Since we get connection errors consistently on Travis
when trying to upload coverage results for Python 2.6,
avoid computing coverage entirely to speed-up tests.

.github/workflows/linux_unit_tests.yaml

@@ -60,3 +60,83 @@ jobs:
       uses: codecov/codecov-action@v1
       with:
         flags: unittests,linux
+  flake8:
+    runs-on: ubuntu-latest
+    steps:
+    - uses: actions/checkout@v2
+    - uses: actions/setup-python@v2
+      with:
+        python-version: 3.8
+    - name: Install Python packages
+      run: |
+        pip install --upgrade pip six setuptools flake8
+    - name: Setup git configuration
+      run: |
+        # Need this for the git tests to succeed.
+        git --version
+        git config --global user.email "spack@example.com"
+        git config --global user.name "Test User"
+        git fetch -u origin develop:develop
+    - name: Run flake8 tests
+      run: |
+          share/spack/qa/run-flake8-tests
+  shell:
+    runs-on: ubuntu-latest
+    steps:
+    - uses: actions/checkout@v2
+    - uses: actions/setup-python@v2
+      with:
+        python-version: 3.8
+    - name: Install System packages
+      run: |
+          sudo apt-get -y update
+          sudo apt-get install -y coreutils gfortran gnupg2 mercurial ninja-build patchelf zsh fish
+          # Needed for kcov
+          sudo apt-get -y install cmake binutils-dev libcurl4-openssl-dev zlib1g-dev libdw-dev libiberty-dev
+    - name: Install Python packages
+      run: |
+          pip install --upgrade pip six setuptools codecov coverage
+    - name: Setup git configuration
+      run: |
+          # Need this for the git tests to succeed.
+          git --version
+          git config --global user.email "spack@example.com"
+          git config --global user.name "Test User"
+          git fetch -u origin develop:develop
+    - name: Install kcov for bash script coverage
+      env:
+          KCOV_VERSION: 38
+      run: |
+          KCOV_ROOT=$(mktemp -d)
+          wget --output-document=${KCOV_ROOT}/${KCOV_VERSION}.tar.gz https://github.com/SimonKagstrom/kcov/archive/v${KCOV_VERSION}.tar.gz
+          tar -C ${KCOV_ROOT} -xzvf ${KCOV_ROOT}/${KCOV_VERSION}.tar.gz
+          mkdir -p ${KCOV_ROOT}/build
+          cd ${KCOV_ROOT}/build && cmake -Wno-dev ${KCOV_ROOT}/kcov-${KCOV_VERSION} && cd -
+          make -C ${KCOV_ROOT}/build && sudo  make -C ${KCOV_ROOT}/build install
+    - name: Run shell tests
+      env:
+          COVERAGE: true
+      run: |
+          share/spack/qa/run-shell-tests
+    - name: Upload to codecov.io
+      uses: codecov/codecov-action@v1
+      with:
+        flags: shelltests,linux
+  documentation:
+    runs-on: ubuntu-latest
+    steps:
+    - uses: actions/checkout@v2
+    - uses: actions/setup-python@v2
+      with:
+        python-version: 3.8
+    - name: Install System packages
+      run: |
+        sudo apt-get -y update
+        sudo apt-get install -y coreutils ninja-build graphviz
+    - name: Install Python packages
+      run: |
+        pip install --upgrade pip six setuptools
+        pip install --upgrade -r lib/spack/docs/requirements.txt
+    - name: Build documentation
+      run: |
+          share/spack/qa/run-doc-tests