Added unit tests to Github Actions (#16610)

* Added unit tests to Github Actions

* Set user e-mail and name for git tests to succeed

* Simplify setup.sh logic

* Replicate Travis script on Github Actions

* Update flags since '.' is not allowed

* Added badge, simplified workflow

* Remove pinning of coverage

* Remove unit tests run on Github Actions from Travis

.github/workflows/linux_unit_tests.yaml

@@ -0,0 +1,61 @@
+name: linux tests
+
+on:
+  push:
+    branches:
+      - master
+      - develop
+  pull_request:
+    branches:
+      - master
+      - develop
+jobs:
+  unittests:
+    runs-on: ubuntu-latest
+    strategy:
+      matrix:
+        python-version: [2.7, 3.5, 3.6, 3.7, 3.8]
+
+    steps:
+    - uses: actions/checkout@v2
+    - name: Setup Python ${{ matrix.python-version }}
+      uses: actions/setup-python@v2
+      with:
+        python-version: ${{ matrix.python-version }}
+    - name: Install System packages
+      run: |
+          sudo apt-get -y update
+          sudo apt-get install -y coreutils gfortran graphviz gnupg2 mercurial ninja-build patchelf
+          # Needed for kcov
+          sudo apt-get -y install cmake binutils-dev libcurl4-openssl-dev zlib1g-dev libdw-dev libiberty-dev
+    - name: Install Python packages
+      run: |
+          pip install --upgrade pip six setuptools codecov coverage
+    - name: Setup git configuration
+      run: |
+          # Need this for the git tests to succeed.
+          git --version
+          git config --global user.email "spack@example.com"
+          git config --global user.name "Test User"
+          git fetch -u origin develop:develop
+    - name: Install kcov for bash script coverage
+      env:
+          KCOV_VERSION: 34
+      run: |
+          KCOV_ROOT=$(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 unit tests
+      env:
+          COVERAGE: true
+      run: |
+          share/spack/qa/run-unit-tests
+          coverage combine
+          coverage xml
+    - name: Upload to codecov.io
+      uses: codecov/codecov-action@v1
+      with:
+        flags: unittests,linux