Diff engine param

.github/workflows/build.yml

@@ -54,6 +54,8 @@ jobs:
 
     steps:
       - uses: actions/checkout@v5
+        with:
+          submodules: recursive
       - name: Set Additional Envs
         run: |
           echo "PYTHON_SUBVERSION=$(echo $PYTHON_VERSION | cut -c 3-)" >> $GITHUB_ENV
@@ -114,6 +116,8 @@ jobs:
 
     steps:
       - uses: actions/checkout@v5
+        with:
+          submodules: recursive
       - uses: actions/setup-python@v6
         with:
           python-version: ${{ matrix.python-version }}

.github/workflows/test_backends.yml

@@ -16,6 +16,8 @@ jobs:
         with:
           python-version: "3.12"
       - uses: actions/checkout@v5
+        with:
+          submodules: recursive
       - name: Install cvxpy dependencies
         run: |
           pip install -e .

.github/workflows/test_nlp_solvers.yml

@@ -0,0 +1,46 @@
+name: test_nlp_solvers
+
+on:
+    pull_request:
+    push:
+        branches:
+            - master
+        tags:
+          - '*'
+jobs:
+  run_nlp_tests:
+    runs-on: ${{ matrix.os }}
+    defaults:
+      run:
+        shell: bash -l {0}
+    strategy:
+      fail-fast: false
+      matrix:
+        os: [ubuntu-latest, macos-latest]
+    steps:
+      - uses: actions/setup-python@v6
+        with:
+          python-version: "3.12"
+      - uses: actions/checkout@v5
+        with:
+          submodules: recursive
+      - name: Set up Conda
+        uses: conda-incubator/setup-miniconda@v3
+        with:
+          activate-environment: nlp-test
+          python-version: 3.12
+          channels: conda-forge
+          channel-priority: strict
+          auto-update-conda: true
+          miniforge-version: latest
+          use-mamba: true
+      - name: Install cyipopt via conda
+        run: |
+          conda install -y -c conda-forge cyipopt
+      - name: Install test dependencies
+        run: |
+          pip install -e .
+          pip install pytest hypothesis
+      - name: Run nlp tests
+        run: |
+          pytest -s -v cvxpy/tests/nlp_tests/.

.github/workflows/test_optional_solvers.yml

@@ -31,7 +31,6 @@ jobs:
         with:
           python-version: 3.12
           enable-cache: true
-      - uses: actions/checkout@v5
       - name: Setup Julia 
         uses: julia-actions/setup-julia@v2
         with: