refactor(ci): generate unit test workflow matrix dynamically

this will allow us to have different matrix expansions for different
use cases, will be used to add iterative expansion on infrequent schedule
or on workflow dispatch with parameters to add statistical power to
flake-hunting attempts

.github/workflows/tests_unit.yml

@@ -19,23 +19,43 @@ concurrency:
   cancel-in-progress: true
 
 jobs:
+  # We want to generate our matrix dynamically
+  # Initial job generates the matrix as a JSON, and following job will use deserialize and use the result
+  matrix_prep:
+    runs-on: ubuntu-latest
+    outputs:
+      matrix: ${{ steps.build-matrix.outputs.result }}
+    steps:
+      - id: build-matrix
+        uses: actions/github-script@v7
+        with:
+          # Notes:
+          # 1) 'os'
+          #   - https://docs.github.com/en/actions/using-github-hosted-runners/about-github-hosted-runners/about-github-hosted-runners#supported-runners-and-hardware-resources
+          #   - macOS 14 is in beta and runs on Apple Silicon [M1]
+          # 2) 'include'
+          #   - define 'name' so we don't need to update branch protection rules if the os changes
+          script: |
+            return {
+              "os": ["ubuntu-latest", "macos-14", "windows-latest"],
+              "include": [
+                {"os": "ubuntu-latest", "name": "ubuntu"},
+                {"os": "macos-14", "name": "macos"},
+                {"os": "windows-latest", "name": "windows"}
+              ]
+            }
+      - name: Debug Output
+        run: echo "${{ steps.build-matrix.outputs.result }}"
+
+  # This uses the matrix generated from the matrix-prep stage
+  # it will run unit tests on whatever OS combinations are desired
   unit:
     name: JUnit Tests (${{ matrix.name }})
+    needs: matrix_prep
     timeout-minutes: 40
     strategy:
       fail-fast: false
-      matrix:
-        # https://docs.github.com/en/actions/using-github-hosted-runners/about-github-hosted-runners/about-github-hosted-runners#supported-runners-and-hardware-resources
-        # macOS 14 is in beta and runs on Apple Silicon [M1]
-        os: [ubuntu-latest, macos-14, windows-latest]
-        # define 'name' so we don't need to update branch protection rules if the os changes
-        include:
-          - os: ubuntu-latest
-            name: ubuntu
-          - os: macos-14
-            name: macos
-          - os: windows-latest
-            name: windows
+      matrix: ${{fromJson(needs.matrix_prep.outputs.matrix)}}
     runs-on: ${{ matrix.os }}
     #env:
     #  CODACY_TOKEN: ${{ secrets.CODACY_TOKEN }}