workflows: add linux-only tests

.github/workflows/tests-linux.yml

@@ -0,0 +1,24 @@
+name: GitHub Actions CI
+on:
+  pull_request:
+    paths:
+      - "Formula/libseccomp.rb"
+jobs:
+  tests_linux:
+    runs-on: ubuntu-latest
+    container:
+      image: homebrew/ubuntu16.04:master
+    env:
+      HOMEBREW_CORE_GIT_REMOTE: ${{github.event.repository.html_url}}
+      HOMEBREW_FORCE_HOMEBREW_ON_LINUX: 1
+    steps:
+      - name: Set up Homebrew
+        uses: Homebrew/actions/setup-homebrew@master
+
+      - run: brew test-bot --only-cleanup-before
+
+      - name: Run brew test-bot --only-formulae
+        run: |
+          mkdir ~/bottles
+          cd ~/bottles
+          brew test-bot --only-formulae

.github/workflows/tests.yml

@@ -28,6 +28,20 @@ jobs:
 
     - run: brew test-bot --only-tap-syntax
 
+    - name: Check .github/workflows/tests-linux.yml formulae coverage
+      run: |
+        FILES=$(grep -oE 'Formula/[a-z0-9_\.\-]+' .github/workflows/tests-linux.yml)
+        for FILE in $FILES; do
+          if [ ! -f "$FILE" ]; then
+            echo ".github/workflows/tests-linux.yml is testing a non existing file: $FILE"
+            exit 1
+          fi
+          if [ ! grep -q "depends_on :linux" "$FILE"]; then
+            echo "$FILE is not a linux-only formula."
+            exit 1
+          fi
+        done
+
   tests:
     needs: tap_syntax
     if: github.event_name == 'pull_request' && ! contains(github.event.pull_request.labels.*.name, 'CI-syntax-only')