diff --git a/.github/workflows/tests.yml b/.github/workflows/tests.yml
index 8848caaf26..474ef457a3 100644
--- a/.github/workflows/tests.yml
+++ b/.github/workflows/tests.yml
@@ -131,6 +131,19 @@ jobs:
           python=${{ matrix.python-version }}
           ${{ env.CONDA_CHANNEL_LABEL }}${{ env.CONDA_VERSION }}
 
+      - name: Checkout development conda
+        uses: actions/checkout@44c2b7a8a4ea60a981eaca3cf939b5f4305c123b # v4.1.5
+        with:
+          repository: zklaus/conda.git
+          ref: lazy-index
+          path: conda-src
+
+      - name: Install development conda
+        run: |
+          cd conda-src
+          pip install -e .
+          cd ..
+
       # TODO: how can we remove this step?
       - name: Install Self
         run: pip install -e .