Handle the argument deserialize_method in mocked data sources.

tensorflow_datasets/testing/mocking.py

@@ -44,12 +44,13 @@
 import tree
 
 
-def _get_fake_data_components(decoders, features):
+def _get_fake_data_components(decoders, features, deserialize_method=None):
   """Gets all the components to generate fake data in the tests.
 
   Args:
     decoders: The decoders to override, or `None` if no decoding is used.
     features: The original features.
+    deserialize_method: The deserialize method to use.
 
   Returns:
     A tuple with the data generator class, the features, the feature specs and
@@ -64,18 +65,27 @@ def _get_fake_data_components(decoders, features):
   else:
     decoders = decoders  # pylint: disable=self-assigning-variable
 
-  has_nested_dataset = any(
-      isinstance(f, features_lib.Dataset) for f in features._flatten(features)  # pylint: disable=protected-access
-  )
-  if decoders is not None or has_nested_dataset:
-    # If a decoder is passed, encode/decode the examples.
-    generator_cls = EncodedRandomFakeGenerator
+  if deserialize_method == decode.DeserializeMethod.RAW_BYTES:
+    generator_cls = SerializedRandomFakeGenerator
     specs = features.get_serialized_info()
-    decode_fn = functools.partial(features.decode_example, decoders=decoders)
-  else:
-    generator_cls = RandomFakeGenerator
-    specs = features.get_tensor_info()
     decode_fn = lambda ex: ex  # identity
+  else:
+    has_nested_dataset = any(
+        isinstance(f, features_lib.Dataset) for f in features._flatten(features)  # pylint: disable=protected-access
+    )
+    if (
+        decoders is not None
+        or has_nested_dataset
+        or deserialize_method == decode.DeserializeMethod.DESERIALIZE_NO_DECODE
+    ):
+      # If a decoder is passed, encode/decode the examples.
+      generator_cls = EncodedRandomFakeGenerator
+      specs = features.get_serialized_info()
+      decode_fn = functools.partial(features.decode_example, decoders=decoders)
+    else:
+      generator_cls = RandomFakeGenerator
+      specs = features.get_tensor_info()
+      decode_fn = lambda ex: ex  # identity
   return generator_cls, features, specs, decode_fn
 
 
@@ -352,7 +362,9 @@ def mock_as_dataset(self, split, decoders=None, read_config=None, **kwargs):
 
     return ds
 
-  def mock_as_data_source(self, split, decoders=None, **kwargs):
+  def mock_as_data_source(
+      self, split, decoders=None, deserialize_method=None, **kwargs
+  ):
     """Mocks `builder.as_data_source`."""
     del kwargs
     nonlocal mock_array_record_data_source
@@ -362,7 +374,7 @@ def mock_as_data_source(self, split, decoders=None, **kwargs):
       split = {s: s for s in self.info.splits}
 
     generator_cls, features, _, _ = _get_fake_data_components(
-        decoders, self.info.features
+        decoders, self.info.features, deserialize_method=deserialize_method
     )
     generator = generator_cls(features, num_examples)
 

tensorflow_datasets/testing/mocking_test.py

@@ -372,6 +372,15 @@ def test_mock_data_source():
     )
     assert isinstance(data_source[0]['image'], bytes)
 
+    # Without deserializing the examples
+    data_source = tfds.data_source(
+        'imagenet2012',
+        split='train',
+        deserialize_method=tfds.decode.DeserializeMethod.RAW_BYTES,
+    )
+    assert len(data_source) == 10
+    assert isinstance(data_source[0], bytes)
+
 
 def test_mock_multiple_data_source():
   with tfds.testing.mock_data(num_examples=10):