Move the pngsuite test (which tests the PNG reader code) into the regression test framework.

Author: mdboom

examples/tests/pngsuite/pngsuite.py

@@ -0,0 +1,29 @@
+from matplotlib.testing.decorators import image_comparison, knownfailureif
+from matplotlib import pyplot as plt
+import matplotlib.cm as cm
+import glob
+import os
+
+@image_comparison(baseline_images=['pngsuite'])
+def test_pngsuite():
+    dirname = os.path.join(
+        os.path.dirname(__file__),
+        'baseline_images',
+        'pngsuite')
+    files = glob.glob(os.path.join(dirname, 'basn*.png'))
+    files.sort()
+
+    fig = plt.figure(figsize=(len(files), 2))
+
+    for i, fname in enumerate(files):
+        data = plt.imread(fname)
+        cmap = None # use default colormap
+        if data.ndim==2:
+            # keep grayscale images gray
+            cmap = cm.gray
+        plt.imshow(data, extent=[i,i+1,0,1], cmap=cmap)
+
+    plt.gca().get_frame().set_facecolor("#ddffff")
+    plt.gca().set_xlim(0, len(files))
+
+    fig.savefig('pngsuite')