Return '' for unsupported export type

Fixed the bug where unsupported export types throw 400 assertion error instead of 400 exporter error. Remove the misleading comment which wrongly claims that `get_exporter_name()` is always called with a supported exporter. Update tests accordingly.

Author: cslzchen

mfr/core/utils.py

@@ -112,12 +112,11 @@ def get_renderer_name(name: str) -> str:
  ep_iterator = pkg_resources.iter_entry_points(group='mfr.renderers', name=name.lower())
  ep_list = list(ep_iterator)
 
- # Empty list indicates unsupported file type.
- # Return a blank string and let `make_renderer()` handle it.
+ # Empty list indicates unsupported file type. Return '' and let `make_renderer()` handle it.
  if len(ep_list) == 0:
  return ''
 
- # If file type is supported, there must be only one element in the list.
+ # If the file type is supported, there must be only one element in the list.
  assert len(ep_list) == 1
  return ep_list[0].attrs[0]
 
@@ -135,7 +134,11 @@ def get_exporter_name(name: str) -> str:
  ep_iterator = pkg_resources.iter_entry_points(group='mfr.exporters', name=name.lower())
  ep_list = list(ep_iterator)
 
- # `make_renderer()` is called before `make_exporter()` to ensure the file type is supported
+ # Empty list indicates unsupported export type. Return '' and let `make_exporter()` handle it.
+ if len(ep_list) == 0:
+ return ''
+
+ # If the export type is supported, there must be only one element in the list.
  assert len(ep_list) == 1
  return ep_list[0].attrs[0]
 

tests/core/test_utils.py

@@ -36,5 +36,4 @@ def test_get_exporter_name(self):
  assert mfr_utils.get_exporter_name(ep.name) == expected
 
  def test_get_exporter_name_no_entry_point(self):
- with pytest.raises(AssertionError):
- mfr_utils.get_exporter_name('jpg')
+ assert mfr_utils.get_exporter_name('jpg') == ''