Download tri-pp in CI and add macOS

.github/workflows/scala.yml

@@ -2,23 +2,49 @@ name: Scala CI
 
 on:
   push:
-    branches: [ master ]
+    branches: 
+      - master
+      - mac-ci
   pull_request:
-    branches: [ master ]
+    branches: 
+      - master
+      - mac-ci
 
 jobs:
   build:
 
-    runs-on: ubuntu-latest
+    runs-on: ${{ matrix.os }}
+
+    strategy:
+      matrix:
+        os: [ubuntu-20.04, macos-13]
+      fail-fast: true # keep running other os on fail?
 
     steps:
     - uses: actions/checkout@v2
+
     - name: Set up JDK 11
       uses: actions/setup-java@v2
       with:
         java-version: '11'
         distribution: 'adopt'
+
+    - name: Download tri-pp binary
+      run: |
+        if [[ "$RUNNER_OS" == "Linux" ]]; then
+          wget https://github.com/zafer-esen/tri-pp/releases/download/v0.1.4/tri-pp-ubuntu-20.04 -O tri-pp
+        elif [[ "$RUNNER_OS" == "macOS" ]]; then
+          wget https://github.com/zafer-esen/tri-pp/releases/download/v0.1.4/tri-pp-macos-13 -O tri-pp
+          xattr -d com.apple.quarantine tri-pp || true
+        fi
+        chmod +x tri-pp
+
+    - name: Install sbt on macOS
+      if: runner.os == 'macOS'
+      run: brew install sbt
+
     - name: Build
       run: sbt assembly
+
     - name: Test
       run: cd regression-tests; export TERM=xterm; ./runalldirs