test macos too

.github/workflows/ci_nix.yml

@@ -8,8 +8,13 @@ concurrency:
     cancel-in-progress: true
 
 jobs:
-    build-and-test:
-        runs-on: [ubuntu-22.04]
+    build-and-test-nix:
+        strategy:
+            fail-fast: false
+            matrix:
+              # macos-11 uses x86-64 machine, macos-14 uses aarch64  
+              os: [ macos-11, macos-14, ubuntu-22.04 ]
+        runs-on: ${{ matrix.os }}
         steps:
             - uses: actions/checkout@v3
 
@@ -26,4 +31,4 @@ jobs:
             #  the result folder is produced by the previous step
             - name: Run all tests 
               run: nix develop -c sh -c 'export ROC=roc && export EXAMPLES_DIR=./examples/ && ./ci/all_tests.sh'
-
+