Merge branch 'make_mono_channel_zero' into 'staging'

Bug - exporting white_channel equal zero

See merge request !27

model_server/base/roiset.py

@@ -428,7 +428,7 @@ class RoiSet(object):
                     raw.data[:, :, ci, :]
                 )
         else:
-            if white_channel:  # interpret as just a single channel
+            if white_channel is not None:  # interpret as just a single channel
                 assert white_channel < raw.chroma
                 annotate_rgb = False
                 for k in ['contour_channel', 'bounding_box_channel', 'mask_channel']:

tests/test_roiset.py

@@ -251,7 +251,7 @@ class TestRoiSetMultichannelProducts(BaseTestRoiSetMonoProducts, unittest.TestCa
         where = output_path / 'multichannel' / 'mono_2d_patches'
         df_res = self.roiset.export_patches(
             where,
-            white_channel=3,
+            white_channel=0,
             draw_bounding_box=True,
             expanded=True,
             pad_to=256,