Add test for png size

Author: Vayel

tests/test_repr.py

@@ -48,16 +48,26 @@ def test__repr_png_no_image(m):
     assert png is None
 
 
-@pytest.mark.xfail
 def test__repr_png_is_bytes(m_png):
     png = m_png._repr_png_()
     assert isinstance(png, bytes)
 
 
-@pytest.mark.xfail
 @pytest.mark.skipif(sys.version_info < (3, 0),
                     reason="Doesn't work on Python 2.7.")
 def test_valid_png(m_png):
     png = m_png._repr_png_()
     img = PIL.Image.open(io.BytesIO(png))
-    isinstance(img, PIL.PngImagePlugin.PngImageFile)
+    assert isinstance(img, PIL.PngImagePlugin.PngImageFile)
+
+
+@pytest.mark.skipif(sys.version_info < (3, 0),
+                    reason="Doesn't work on Python 2.7.")
+def test_valid_png_size(m_png):
+    from folium.utilities import _parse_size
+    w = h = 500
+    m_png.width = _parse_size(w)
+    m_png.height = _parse_size(h)
+    png = m_png._repr_png_()
+    img = PIL.Image.open(io.BytesIO(png))
+    assert img.size == (w, h)