os: linux # Use linux unless specified otherwise.
dist: xenial
sudo: required

language: cpp

matrix:
  include:
    - os: linux
      compiler: g++
      addons:
        apt:
          sources:
            - ubuntu-toolchain-r-test
          packages:
            - g++-7
      env:
        - CXX_COMPILER=g++-7 CC_COMPILER=gcc-7

    - os: linux
      compiler: g++
      addons:
        apt:
          sources:
            - ubuntu-toolchain-r-test
          packages:
            - g++-8
      env:
        - CXX_COMPILER=g++-8 CC_COMPILER=gcc-8

    - os: linux
      compiler: g++
      addons:
        apt:
          sources:
            - ubuntu-toolchain-r-test
          packages:
            - g++-9
      env:
        - CXX_COMPILER=g++-9 CC_COMPILER=gcc-9

    - os: linux
      compiler: clang++
      addons:
        apt:
          sources:
            - ubuntu-toolchain-r-test
            - sourceline: 'deb https://apt.llvm.org/xenial/ llvm-toolchain-xenial-5.0 main'
              key_url: 'https://apt.llvm.org/llvm-snapshot.gpg.key'
          packages:
            - g++-7
            - clang-5.0
      env:
        - CXX_COMPILER=clang++-5.0 CC_COMPILER=clang-5.0

    - os: linux
      compiler: clang++
      addons:
        apt:
          sources:
            - ubuntu-toolchain-r-test
            - sourceline: 'deb https://apt.llvm.org/xenial/ llvm-toolchain-xenial-6.0 main'
              key_url: 'https://apt.llvm.org/llvm-snapshot.gpg.key'
          packages:
            - g++-7
            - clang-6.0
      env:
        - CXX_COMPILER=clang++-6.0 CC_COMPILER=clang-6.0

    - os: linux
      compiler: clang++
      addons:
        apt:
          sources:
            - ubuntu-toolchain-r-test
            - sourceline: 'deb https://apt.llvm.org/xenial/ llvm-toolchain-xenial-7 main'
              key_url: 'https://apt.llvm.org/llvm-snapshot.gpg.key'
          packages:
            - g++-7
            - clang-7
      env:
        - CXX_COMPILER=clang++-7 CC_COMPILER=clang-7

    - os: linux
      compiler: clang++
      addons:
        apt:
          sources:
            - ubuntu-toolchain-r-test
            - sourceline: 'deb https://apt.llvm.org/xenial/ llvm-toolchain-xenial-8 main'
              key_url: 'https://apt.llvm.org/llvm-snapshot.gpg.key'
          packages:
            - g++-7
            - clang-8
      env:
        - CXX_COMPILER=clang++-8 CC_COMPILER=clang-8

    - os: linux
      compiler: clang++
      addons:
        apt:
          sources:
            - ubuntu-toolchain-r-test
            - sourceline: 'deb https://apt.llvm.org/xenial/ llvm-toolchain-xenial-9 main'
              key_url: 'https://apt.llvm.org/llvm-snapshot.gpg.key'
          packages:
            - g++-7
            - clang-9
      env:
        - CXX_COMPILER=clang++-9 CC_COMPILER=clang-9

    - os: osx
      compiler: clang++
      osx_image: xcode10.3
      env:
        - CXX_COMPILER=clang++ CC_COMPILER=clang

    - os: osx
      compiler: clang++
      osx_image: xcode11.2
      env:
        - CXX_COMPILER=clang++ CC_COMPILER=clang

install:
  - export CC=${CC_COMPILER}
  - export CXX=${CXX_COMPILER}
  - JOBS=2 # Travis machines have 2 cores.

before_script:
  - rm -rf build
  - mkdir -p build
  - cd build
  - cmake -G "Unix Makefiles" ..

script:
  - cmake --build . -- -j${JOBS}
  - ctest --output-on-failure -j${JOBS}

notifications:
  email: false