add a test that should fail since px doesn't support pandas 2

Author: alexcjohnson

Diff for: .circleci/config.yml

@@ -92,7 +92,21 @@ commands:
             cd packages/python/plotly
             . venv/bin/activate
             pytest -x test_init/test_lazy_imports.py
-
+      - run:
+          name: Test PX if Pandas 2
+          command: |
+            if [ "<<parameters.py>>" == "39_pandas_2" ]; then
+              . packages/python/plotly/venv/bin/activate
+              pip install -e ./packages/python/plotly
+              pip install -e ./packages/python/plotly-geo
+              python test/percy/plotly-express.py
+              mkdir test/percy/pandas2
+              mv test/percy/*.html test/percy/pandas2/
+              # 1.1 is the earliest minor with Py3.9 wheels
+              pip install "pandas==1.1.5"
+              python test/percy/plotly-express.py
+              python test/percy/compare-pandas.py
+            fi
   test_orca:
     parameters:
       py:

Diff for: .gitignore

@@ -54,3 +54,4 @@ packages/python/plotly/jupyterlab_plotly/labextension/
 packages/python/plotly/jupyterlab_plotly/nbextension/index.js*
 
 test/percy/*.html
+test/percy/pandas2/*.html

Diff for: test/percy/compare-pandas.py

@@ -0,0 +1,8 @@
+import os
+
+os.chdir(os.path.dirname(__file__))
+
+for filename in os.listdir("pandas2"):
+    with open(filename, encoding="utf-8") as f:
+        with open(os.path.join("pandas2", filename)) as f2:
+            assert f.read() == f2.read(), f"Pandas 1/2 difference in {filename}"