Add test workflow for the msi package

.github/workflows/ci.yaml

@@ -1011,5 +1011,8 @@ jobs:
 
   build-msi-package:
     uses: ./.github/workflows/build-msi.yml
-    if  : github.event_name == 'pull_request' && contains(github.event.pull_request.body, '[test_msi]')
-    # TODO: ADD A JOB THAT DEPENDS ON THIS TO TEST THE MSI
+
+  test-msi-package:
+    uses : ./.github/workflows/test-msi.yml
+    if   : github.event_name == 'pull_request' && contains(github.event.pull_request.body, '[test_msi]')
+    needs: build-msi-package

.github/workflows/test-msi.yml

@@ -0,0 +1,34 @@
+###################################################################################################
+###                        THIS IS A REUSABLE WORKFLOW TO TEST SCALA MSI                        ###
+### HOW TO USE:                                                                                 ###
+###                                                                                             ###
+### NOTE:                                                                                       ###
+###                                                                                             ###
+###################################################################################################
+
+name: Test the MSI package
+
+on:
+  workflow_call:
+
+jobs:
+  test:
+    runs-on: windows-latest
+    steps:
+      - name: Fetch the MSI package from GitHub Artifacts
+        uses: actions/download-artifact@v4
+        with:
+          name: scala.msi
+      - name : Install Scala from the MSI Package
+        run  : |
+          Start-Process msiexec -ArgumentList "/i scala.msi /qn /passive /quiet" -NoNewWindow -Wait
+        shell: pwsh
+      - name : Check that the `scala` command is available
+        run  : scala --version
+        shell: cmd
+      - name : Check that the `scalac` command is available
+        run  : scalac --version
+        shell: cmd
+      - name : Check that the `scaladoc` command is available
+        run  : scaladoc --version
+        shell: cmd