TST: Use compare_images rather than decorator and switch back to unittest.TestCase

tests/test_plotting.py

@@ -1,8 +1,10 @@
 import os
+import tempfile
 import unittest
 
 from matplotlib.pyplot import Artist, savefig
-from matplotlib.testing.decorators import image_comparison
+from matplotlib.testing.noseclasses import ImageComparisonFailure
+from matplotlib.testing.compare import compare_images
 from shapely.geometry import Polygon, LineString, Point
 
 from geopandas import GeoSeries
@@ -10,23 +12,33 @@ from geopandas import GeoSeries
 # If set to True, generate images rather than perform tests (all tests will pass!)
 GENERATE_BASELINE = False
 
+TEMPDIR = tempfile.gettempdir()
 BASELINE_DIR = os.path.join(os.path.dirname(__file__), 'baseline_images', 'test_plotting')
 
-def save_baseline_image(filename):
-    """ save a baseline image """
-    savefig(os.path.join(BASELINE_DIR, filename))
 
-@image_comparison(baseline_images=['poly_plot'], extensions=['png'])
-def test_poly_plot():
-    """ Test plotting a simple series of polygons """
-    t1 = Polygon([(0, 0), (1, 0), (1, 1)])
-    t2 = Polygon([(1, 0), (2, 1), (2, 1)])
-    polys = GeoSeries([t1, t2])
-    ax = polys.plot()
-    assert isinstance(ax, Artist)
-    if GENERATE_BASELINE:
-        save_baseline_image('poly_plot.png')
+class PlotTests(unittest.TestCase):
+    
+    def test_poly_plot(self, tol=8):
+        """ Test plotting a simple series of polygons """
+        filename = 'poly_plot.png'
+        t1 = Polygon([(0, 0), (1, 0), (1, 1)])
+        t2 = Polygon([(1, 0), (2, 0), (2, 1)])
+        polys = GeoSeries([t1, t2])
+        ax = polys.plot()
+        assert isinstance(ax, Artist)
+        if GENERATE_BASELINE:
+            savefig(os.path.join(BASELINE_DIR, filename))
+        savefig(os.path.join(TEMPDIR, filename))
+        err = compare_images(os.path.join(BASELINE_DIR, filename),
+                             os.path.join(TEMPDIR, filename),
+                             tol, in_decorator=True)
+        try:
+            if err:
+                raise ImageComparisonFailure('images not close: %(actual)s '
+                                             'vs. %(expected)s '
+                                             '(RMS %(rms).3f)' % err)
+        finally:
+            os.remove(os.path.join(TEMPDIR, filename))
 
 if __name__ == '__main__':
-    import nose
-    nose.runmodule(argv=['-s', '--with-doctest'])
+    unittest.main()