chore: Add abstract type annotation support to AFC

PiperOrigin-RevId: 831462920

tests/unittests/tools/test_from_function_with_options.py

@@ -12,6 +12,7 @@
 # See the License for the specific language governing permissions and
 # limitations under the License.
 
+from collections.abc import Sequence
 from typing import Any
 from typing import Dict
 
@@ -192,3 +193,52 @@ def test_from_function_with_options_no_params():
   # VERTEX_AI should have response schema for None return
   assert declaration.response is not None
   assert declaration.response.type == types.Type.NULL
+
+
+def test_from_function_with_collections_type_parameter():
+  """Test from_function_with_options with collections type parameter."""
+
+  def test_function(
+      artifact_key: str,
+      input_edit_ids: Sequence[str],
+  ) -> str:
+    """Saves a sequence of edit IDs."""
+    return f'Saved {len(input_edit_ids)} edit IDs for artifact {artifact_key}'
+
+  declaration = _automatic_function_calling_util.from_function_with_options(
+      test_function, GoogleLLMVariant.VERTEX_AI
+  )
+
+  assert declaration.name == 'test_function'
+  assert declaration.parameters.type == types.Type.OBJECT
+  assert (
+      declaration.parameters.properties['artifact_key'].type
+      == types.Type.STRING
+  )
+  assert (
+      declaration.parameters.properties['input_edit_ids'].type
+      == types.Type.ARRAY
+  )
+  assert (
+      declaration.parameters.properties['input_edit_ids'].items.type
+      == types.Type.STRING
+  )
+  assert declaration.response.type == types.Type.STRING
+
+
+def test_from_function_with_collections_return_type():
+  """Test from_function_with_options with collections return type."""
+
+  def test_function(
+      names: list[str],
+  ) -> Sequence[str]:
+    """Returns a sequence of names."""
+    return names
+
+  declaration = _automatic_function_calling_util.from_function_with_options(
+      test_function, GoogleLLMVariant.VERTEX_AI
+  )
+
+  assert declaration.name == 'test_function'
+  assert declaration.response.type == types.Type.ARRAY
+  assert declaration.response.items.type == types.Type.STRING