diff --git a/.github/workflows/python_tests.yaml b/.github/workflows/python_tests.yaml
index 3db1677c..ad40bf2c 100644
--- a/.github/workflows/python_tests.yaml
+++ b/.github/workflows/python_tests.yaml
@@ -39,6 +39,19 @@ jobs:
           mamba install --quiet --file=requirements.txt
           mamba install --quiet --file=test-requirements.txt
 
+      - name: get rubin_sim from main
+        uses: actions/checkout@v3
+        with:
+          repository: lsst/rubin_sim
+          ref: main
+          path: rubin_sim
+
+      - name: install rubin_sim
+        shell: bash -l {0}
+        run: |
+          cd rubin_sim
+          python -m pip install .
+
       - name: download rubin_sim_data components needed for unit tests
         shell: bash -l {0}
         run: |
diff --git a/pyproject.toml b/pyproject.toml
index 811898c5..1b04e313 100644
--- a/pyproject.toml
+++ b/pyproject.toml
@@ -29,7 +29,7 @@ __version__ = "{version}"
 """
 
 [tool.pytest.ini_options]
-addopts = "--black --ignore-glob=*/version.py --ignore-glob=*data_dir/*"
+addopts = "--black --ignore-glob=*/version.py --ignore-glob=*data_dir/* --ignore-glob=*rubin_sim/*"
 testpaths = "."
 
 [tool.black]