Module testing (#1255)

Address issue #1254

---------

Co-authored-by: pre-commit-ci[bot] <66853113+pre-commit-ci[bot]@users.noreply.github.com>
Co-authored-by: Henry Schreiner <HenrySchreinerIII@gmail.com>

.github/workflows/tests.yml

@@ -314,6 +314,29 @@ jobs:
       - name: Run tests
         run: ctest --output-on-failure -L Packaging
         working-directory: build
+        
+  install-module:
+    name: install module tests
+    runs-on: ubuntu-latest
+    container: gcc:15
+    steps:
+      - uses: actions/checkout@v4
+        with:
+          submodules: true
+      - uses: ./.github/actions/quick_cmake
+        with:
+          cmake-version: "4.2"
+      - uses: seanmiddleditch/gha-setup-ninja@master
+      - name: Configure
+        run: cmake -S . -B build -DCLI11_INSTALL_PACKAGE_TESTS=ON -DCLI11_MODULE_TESTS=ON -DCMAKE_INSTALL_PREFIX=/home/runner/work/install -DCMAKE_CXX_STANDARD=23
+      - name: Build
+        run: cmake --build build  -j2
+      - name: install
+        run: cmake --install build
+      - name: Run tests
+        run: ctest --output-on-failure -L Packaging
+        working-directory: build
+
 
   cmake-config-ubuntu-2204:
     name: CMake config check (Ubuntu 22.04)
@@ -449,3 +472,9 @@ jobs:
         with:
           cmake-version: "4.1"
         if: success() || failure()
+      
+      - name: Check CMake 4.2
+        uses: ./.github/actions/quick_cmake
+        with:
+          cmake-version: "4.2"
+        if: success() || failure()