[test] added test for ToTensor transform on grayscale images

bob/learn/pytorch/test/test.py

@@ -111,6 +111,11 @@ def test_transforms():
   tt = ToTensor()
   tt(sample)
   assert isinstance(sample['image'], torch.Tensor)
+  # grayscale 
+  image_gray = numpy.random.rand(128, 128).astype("uint8")
+  sample_gray = {'image': image_gray}
+  tt(sample_gray)
+  assert isinstance(sample['image'], torch.Tensor)
 
   from ..datasets import Normalize
   image_copy = torch.Tensor(sample['image'])