TST: add helper script to compare images in the browser

jankatins · jankatins · commit 9c353f07873f · 2016-01-26T23:42:53.000+01:00
This is a script which I developed for ggplot https://github.com/yhat/ggplot/blob/master/visual_tests.py The script will go over the images in result_images and add them to a webpage, sorted by test files. At the top, there will be the test failures, so you can inspect the visually and try to figure out what's wrong with matplotlib (or the tests...) :-)
diff --git a/visual_tests.py b/visual_tests.py
@@ -0,0 +1,91 @@
+#!/usr/bin/env python
+#
+# This builds a html page of all images from the image comparison tests
+# and opens that page in the browser.
+#
+#   $ python visual_tests.py
+#
+
+import os
+import time
+import six
+
+from collections import defaultdict
+
+def run():
+    # Build a website for visual comparison
+    image_dir = "result_images"
+    # build the website
+    _html = ""
+    _html += """<html><head><style media="screen" type="text/css">
+    img{
+        width:100%;
+        max-width:800px;
+    }
+    </style>
+    </head><body>\n"""
+    _subdirs = [name for name in os.listdir(image_dir) if os.path.isdir(os.path.join(image_dir, name))]
+    # loop over all pictures
+    _row = '<tr><td>{0} {1}</td><td>{2}</td><td><a href="{3}"><img src="{3}"></a></td><td>{4}</td>\n'
+    _failed = ""
+    _failed += "<h2>Only Failed</h2>"
+    _failed += "<table>\n<thead><td>name</td><td>actual</td><td>expected</td><td>diff</td></thead>\n"
+    _has_failure = False
+    _body = ""
+    for subdir in _subdirs:
+        if subdir == "test_compare_images":
+            # these are the image which test the image comparison functions...
+            continue
+        pictures = defaultdict(dict)
+        for file in os.listdir(os.path.join(image_dir, subdir)):
+            if os.path.isdir(os.path.join(image_dir, subdir, file)):
+                continue
+            fn, fext = os.path.splitext(file)
+            if fext != ".png":
+                continue
+            if "-failed-diff" in fn:
+                pictures[fn[:-12]]["f"] = os.path.join(subdir, file)
+            elif "-expected" in fn:
+                pictures[fn[:-9]]["e"] = os.path.join(subdir, file)
+            else:
+                pictures[fn]["c"] = os.path.join(subdir, file)
+        
+        _body += "<h2>{0}</h2>".format(subdir)
+        _body += "<table>\n<thead><td>name</td><td>actual</td><td>expected</td><td>diff</td></thead>\n"
+        for name, test in six.iteritems(pictures):
+            if test.get("f", None):
+                # a real failure in the image generation, resulting in different images
+                _has_failure = True
+                s = "(failed)"
+                failed = '<a href="{0}">diff</a>'.format(test.get("f", ""))
+                current = '<a href="{0}"><img src="{0}"></a>'.format(test.get("c", ""))
+                _failed += _row.format(name, "", current, test.get("e", ""), failed)
+            elif test.get("c", None) is None:
+                # A failure in the test, resulting in no current image
+                _has_failure = True
+                s = "(failed)"
+                failed = '--'
+                current = '(Failure in test, no image produced)'
+                _failed += _row.format(name, "", current, test.get("e", ""), failed)
+            else:
+                s = "(passed)"
+                failed = '--'
+                current = '<a href="{0}"><img src="{0}"></a>'.format(test.get("c", ""))
+            _body += _row.format(name, "", current, test.get("e", ""), failed)
+        _body += "</table>\n"
+    _failed += "</table>\n"
+    if _has_failure:
+        _html += _failed
+    _html += _body
+    _html += "\n</body></html>"
+    index = os.path.join(image_dir, "index.html")
+    with open(index, "w") as f:
+        f.write(_html)
+    try:
+        import webbrowser
+        webbrowser.open(index)
+    except:
+        print("Open {0} in a browser for a visual comparison.".format(str(index)))
+
+if __name__ == '__main__':
+    run()
