pandas 1/2 px comparison: looser equality of just the figure spec

Author: alexcjohnson

Diff for: .circleci/config.yml

@@ -275,6 +275,8 @@ jobs:
             npx percy snapshot -c test/percy/snapshots.yml test/percy/
             rm test/percy/*.html
             rm -rf test/percy/pandas2
+      - store_artifacts:
+          path: test/percy
 
   # Chart studio
   python_37_chart_studio:

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

@@ -1,8 +1,26 @@
+import difflib
+import json
 import os
 
 os.chdir(os.path.dirname(__file__))
 
+def clean_float(numstr):
+    # round numbers to 3 digits, to remove floating-point differences
+    return round(float(numstr), 3)
+
+def get_fig(html):
+    # strip off all the rest of the html and js
+    fig_str = html[html.index('[{', html.rindex('Plotly.newPlot(')):]
+    fig_str = fig_str[:fig_str.index('}    ') + 1]
+    data, layout, config = json.loads(f'[{fig_str}]', parse_float=clean_float)
+    fig_dict = dict(data=data, layout=layout, config=config)
+    return json.dumps(fig_dict, indent=2).splitlines(keepends=True)
+
 for filename in os.listdir("pandas2"):
-    with open(filename, encoding="utf-8") as f:
+    with open(filename, encoding="utf-8") as f1:
         with open(os.path.join("pandas2", filename)) as f2:
-            assert f.read() == f2.read(), f"Pandas 1/2 difference in {filename}"
+            fig1 = get_fig(f1.read())
+            fig2 = get_fig(f2.read())
+            if any(l1 != l2 for l1, l2 in zip(fig1, fig2)):
+                print(''.join(difflib.unified_diff(fig1, fig2)))
+                raise ValueError(f"Pandas 1/2 difference in {filename}")