diff --git a/tests/visual_tests/test.py b/tests/visual_tests/test.py
index ddcec05bf..f9f46f257 100755
--- a/tests/visual_tests/test.py
+++ b/tests/visual_tests/test.py
@@ -7,8 +7,7 @@ import os.path
 from compare import compare, summary
 
 defaults = {
-    'sizes': [(500, 100)],
-    'bbox': mapnik.Box2d(-0.05, -0.01, 0.95, 0.01)
+    'sizes': [(500, 100)]
 }
 
 sizes_many_in_big_range = [(800, 100), (600, 100), (400, 100),
@@ -18,33 +17,36 @@ sizes_few_square = [(800, 800), (600, 600), (400, 400), (200, 200)]
 sizes_many_in_small_range = [(490, 100), (495, 100), (497, 100), (498, 100),
     (499, 100), (500, 100), (501, 100), (502, 100), (505, 100), (510, 100)]
 
+default_text_box = mapnik.Box2d(-0.05, -0.01, 0.95, 0.01)
+
 dirname = os.path.dirname(__file__)
 
 files = [
-    {'name': "list", 'sizes': sizes_many_in_big_range},
-    {'name': "simple", 'sizes': sizes_many_in_big_range},
-    {'name': "lines-1", 'sizes': sizes_few_square},
-    {'name': "lines-2", 'sizes': sizes_few_square},
-    {'name': "lines-3", 'sizes': sizes_few_square},
-    {'name': "lines-shield", 'sizes': sizes_few_square},
-    {'name': "simple-E"},
-    {'name': "simple-NE"},
-    {'name': "simple-NW"},
-    {'name': "simple-N"},
-    {'name': "simple-SE"},
-    {'name': "simple-SW"},
-    {'name': "simple-S"},
-    {'name': "simple-W"},
-    {'name': "formatting-1"},
-    {'name': "formatting-2"},
-    {'name': "formatting-3"},
-    {'name': "formatting-4"},
-    {'name': "expressionformat"},
-    {'name': "shieldsymbolizer-1", 'sizes': sizes_many_in_small_range},
-    {'name': "rtl-point", 'sizes': [(200, 200)]},
-    {'name': "jalign-auto", 'sizes': [(200, 200)]},
-    {'name': "line-offset", 'sizes':[(900, 250)],
-        'bbox': mapnik.Box2d(-5.192, 50.189, -5.174, 50.195)},
+    {'name': "list", 'sizes': sizes_many_in_big_range,'bbox':default_text_box},
+    {'name': "simple", 'sizes': sizes_many_in_big_range,'bbox':default_text_box},
+    {'name': "lines-1", 'sizes': sizes_few_square,'bbox':default_text_box},
+    {'name': "lines-2", 'sizes': sizes_few_square,'bbox':default_text_box},
+    {'name': "lines-3", 'sizes': sizes_few_square,'bbox':default_text_box},
+    {'name': "lines-shield", 'sizes': sizes_few_square,'bbox':default_text_box},
+    {'name': "simple-E", 'bbox':mapnik.Box2d(-0.05, -0.01, 0.95, 0.01)},
+    {'name': "simple-NE",'bbox':default_text_box},
+    {'name': "simple-NW",'bbox':default_text_box},
+    {'name': "simple-N",'bbox':default_text_box},
+    {'name': "simple-SE",'bbox':default_text_box},
+    {'name': "simple-SW",'bbox':default_text_box},
+    {'name': "simple-S",'bbox':default_text_box},
+    {'name': "simple-W",'bbox':default_text_box},
+    {'name': "formatting-1",'bbox':default_text_box},
+    {'name': "formatting-2",'bbox':default_text_box},
+    {'name': "formatting-3",'bbox':default_text_box},
+    {'name': "formatting-4",'bbox':default_text_box},
+    {'name': "expressionformat",'bbox':default_text_box},
+    {'name': "shieldsymbolizer-1", 'sizes': sizes_many_in_small_range,'bbox':default_text_box},
+    {'name': "rtl-point", 'sizes': [(200, 200)],'bbox':default_text_box},
+    {'name': "jalign-auto", 'sizes': [(200, 200)],'bbox':default_text_box},
+    {'name': "line-offset", 'sizes':[(900, 250)],'bbox': mapnik.Box2d(-5.192, 50.189, -5.174, 50.195)},
+    {'name': "tiff-alpha-gdal", 'sizes':[(600,400)]},
+    {'name': "tiff-alpha-raster", 'sizes':[(600,400)]},
     ]
 
 def render(filename, width, height, bbox, quiet=False):
@@ -89,7 +91,7 @@ if __name__ == "__main__":
             config = dict(defaults)
             config.update(f)
             for size in config['sizes']:
-                m = render(config['name'], size[0], size[1], config['bbox'], quiet=quiet)
+                m = render(config['name'], size[0], size[1], config.get('bbox'), quiet=quiet)
             mapnik.save_map(m, os.path.join(dirname, 'xml_output', "%s-out.xml" % config['name']))
 
-        summary()
+        summary(generate=False)