Migrate build tests from Travis to Github Actions (#13967)

This PR moves build smoke tests from TravisCI and migrates them to Github Actions. The result is that build tests are performed in parallel with unit tests and they don't hog additional resources on Travis. The workflow will not run if a PR only changes packages in the built-in repository, but will always run on pushes to develop or master.

* Removed build tests from Travis and passed them to Github Actions
* Store ~/.ccache in Github Actions cache
* Add filters on paths and make sure this workflow don't run
* Use paths-ignore and exclude only files in the built-in repo
* Added a badge to README.md

4 files changed, 74 insertions, 50 deletions

diff --git a/.github/workflows/build_tests_linux.yaml b/.github/workflows/build_tests_linux.yaml
new file mode 100644
index 0000000000..15aaa19f06
--- /dev/null
+++ b/.github/workflows/build_tests_linux.yaml
@@ -0,0 +1,57 @@
+name: Build Tests Linux
+
+on:
+  push:
+    branches:
+    - master
+    - develop
+  pull_request:
+    branches:
+    - master
+    - develop
+    paths-ignore:
+      # Don't run if we only modified packages in the built-in repository
+      - 'var/spack/repos/builtin/**'
+      - '!var/spack/repos/builtin/packages/lz4/**'
+      - '!var/spack/repos/builtin/packages/mpich/**'
+      - '!var/spack/repos/builtin/packages/tut/**'
+      - '!var/spack/repos/builtin/packages/py-setuptools/**'
+      - '!var/spack/repos/builtin/packages/openjpeg/**'
+      - '!var/spack/repos/builtin/packages/r-rcpp/**'
+
+jobs:
+  build:
+
+    runs-on: ubuntu-latest
+    strategy:
+      max-parallel: 4
+      matrix:
+        package: [lz4, mpich, tut, py-setuptools, openjpeg, r-rcpp]
+    steps:
+    - uses: actions/checkout@v1
+    - name: Cache ccache's store
+      uses: actions/cache@v1
+      with:
+        path: ~/.ccache
+        key: ccache-build-${{ matrix.package }}
+        restore-keys: |
+          ccache-build-${{ matrix.package }}
+    - name: Setup Python
+      uses: actions/setup-python@v1
+      with:
+        python-version: 3.8
+    - name: Install System Packages
+      run: |
+        sudo apt-get -yqq install ccache gfortran perl perl-base r-base r-base-core r-base-dev findutils openssl libssl-dev libpciaccess-dev
+        R --version
+        perl --version
+    - name: Copy Configuration
+      run: |
+        ccache -M 300M && ccache -z
+        # Set up external deps for build tests, b/c they take too long to compile
+        cp share/spack/qa/configuration/*.yaml etc/spack/
+    - name: Run the build test
+      run: |
+        . share/spack/setup-env.sh
+        SPEC=${{ matrix.package }} share/spack/qa/run-build-tests
+        ccache -s
diff --git a/.travis.yml b/.travis.yml
index f276c3ba34..86b9f4d3db 100644
--- a/.travis.yml
+++ b/.travis.yml
@@ -61,52 +61,10 @@ jobs:
       language: generic
       env: [ TEST_SUITE=unit, PYTHON_VERSION=2.7, COVERAGE=true ]
       if: type != pull_request
-# mpich (AutotoolsPackage)
-    - stage: 'build tests'
-      python: '2.7'
-      os: linux
-      language: python
-      env: [ TEST_SUITE=build, 'SPEC=mpich' ]
-# astyle (MakefilePackage)
-    - python: '3.8'
-      os: linux
-      language: python
-      env: [ TEST_SUITE=build, 'SPEC=astyle' ]
-# tut (WafPackage)
-    - python: '3.8'
-      os: linux
-      language: python
-      env: [ TEST_SUITE=build, 'SPEC=tut' ]
-# py-setuptools (PythonPackage)
-    - python: '3.8'
-      os: linux
-      language: python
-      env: [ TEST_SUITE=build, 'SPEC=py-setuptools' ]
-# perl-dbi (PerlPackage)
-#    - python: '3.8'
-#      os: linux
-#      language: python
-#      env: [ TEST_SUITE=build, 'SPEC=perl-dbi' ]
-# openjpeg (CMakePackage + external cmake)
-    - python: '3.8'
-      os: linux
-      language: python
-      env: [ TEST_SUITE=build, 'SPEC=openjpeg' ]
-# r-rcpp (RPackage + external R)
-    - python: '3.8'
-      os: linux
-      language: python
-      env: [ TEST_SUITE=build, 'SPEC=r-rcpp' ]
-# mpich (AutotoolsPackage)
-    - python: '3.8'
-      os: linux
-      language: python
-      env: [ TEST_SUITE=build, 'SPEC=mpich' ]
 
 stages:
   - 'style checks'
   - 'unit tests + documentation'
-  - 'build tests'
 
 
 #=============================================================================
@@ -182,11 +140,6 @@ before_script:
   # Need this to be able to compute the list of changed files
   - git fetch origin ${TRAVIS_BRANCH}:${TRAVIS_BRANCH}
 
-  # Set up external deps for build tests, b/c they take too long to compile
-  - if [[ "$TEST_SUITE" == "build" ]]; then
-        cp share/spack/qa/configuration/*.yaml etc/spack/;
-    fi
-
 #=============================================================================
 # Building
 #=============================================================================
diff --git a/README.md b/README.md
index 2f0d5dfd8f..51155f9cb5 100644
--- a/README.md
+++ b/README.md
@@ -1,6 +1,7 @@
 # <img src="https://cdn.rawgit.com/spack/spack/develop/share/spack/logo/spack-logo.svg" width="64" valign="middle" alt="Spack"/> Spack
 
 [![Build Status](https://travis-ci.org/spack/spack.svg?branch=develop)](https://travis-ci.org/spack/spack)
+[![](https://github.com/spack/spack/workflows/Build%20Tests%20Linux/badge.svg)](https://github.com/spack/spack/actions)
 [![codecov](https://codecov.io/gh/spack/spack/branch/develop/graph/badge.svg)](https://codecov.io/gh/spack/spack)
 [![Read the Docs](https://readthedocs.org/projects/spack/badge/?version=latest)](https://spack.readthedocs.io)
 [![Slack](https://spackpm.herokuapp.com/badge.svg)](https://spackpm.herokuapp.com)
diff --git a/share/spack/qa/configuration/packages.yaml b/share/spack/qa/configuration/packages.yaml
index fad3489d3b..076095a7ca 100644
--- a/share/spack/qa/configuration/packages.yaml
+++ b/share/spack/qa/configuration/packages.yaml
@@ -2,12 +2,25 @@ packages:
   cmake:
     buildable: False
     paths:
-      cmake@2.8.12.2: /usr
+      cmake@3.12.4: /usr
   r:
     buildable: False
     paths:
-      r@3.0.2: /usr
+      r@3.4.4: /usr
   perl:
     buildable: False
     paths:
-      perl@5.18.2: /usr
+      perl@5.26.1: /usr
+  findutils:
+    buildable: False
+    paths:
+      findutils@4.6.0: /usr
+  openssl:
+    buildable: False
+    paths:
+      openssl@1.1.1: /usr
+  libpciaccess:
+    buildable: False
+    paths:
+      libpciaccess@0.13.5: /usr
+