build: separate tests to different instances

When we are allocating `cpus`, we need to ensure they roughly match the
core count used by the CI, otherwise there is a risk of GitHub shutting
the runner down due to overloading.

.github/workflows/test.yml

@@ -15,6 +15,12 @@ jobs:
     name: Test
     runs-on: macos-12
     continue-on-error: ${{ inputs.continue-on-error }}
+    strategy:
+      matrix:
+        platform-name:
+          - workstation-pop-os
+          - server-nas
+          - server-pi
 
     steps:
       - name: Checkout
@@ -58,4 +64,4 @@ jobs:
           restore-keys: ${{ runner.os }}-vagrant-
 
       - name: Test
-        run: just test
+        run: just test --platform-name ${{ matrix.platform-name }}

ansible/molecule/default/molecule.yml

@@ -12,9 +12,11 @@ driver:
 platforms:
   - name: workstation-pop-os
     groups: [workstations]
-    # `cpus` need to roughly match the core count used by the CI. Currently, we
-    # are using a 3-core macos-12 instance in '.github/workflows/test.yml',
-    # therefore we are using 2x 2-core instances with vagrant.
+    # `cpus` need to roughly match the core count used by the CI, otherwise
+    # there is a risk of GitHub shutting the runner down due to overloading.
+    # Currently, we are using a 3-core macos-12 instance in
+    # '.github/workflows/test.yml' which runs a single vagrant instance per
+    # matrix test, therefore we are using 2 cores per instance with vagrant.
     # See:
     # https://docs.github.com/en/actions/using-github-hosted-runners/about-github-hosted-runners#supported-runners-and-hardware-resources
     cpus: 2