chore: import upstream snapshot with attribution

tests/unittests/utils/test_content_utils.py

@@ -0,0 +1,68 @@
+# Copyright 2026 Google LLC
+#
+# Licensed under the Apache License, Version 2.0 (the "License");
+# you may not use this file except in compliance with the License.
+# You may obtain a copy of the License at
+#
+#     http://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing, software
+# distributed under the License is distributed on an "AS IS" BASIS,
+# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+# See the License for the specific language governing permissions and
+# limitations under the License.
+
+from __future__ import annotations
+
+from google.adk.utils.content_utils import SKIP_THOUGHT_SIGNATURE_VALIDATOR
+from google.adk.utils.content_utils import to_user_content
+from google.genai import types
+from pydantic import BaseModel
+
+
+def test_skip_thought_signature_validator_wire_value():
+  # The backend recognizes this exact byte string to bypass validation;
+  # changing it would break every replayed synthetic part.
+  assert SKIP_THOUGHT_SIGNATURE_VALIDATOR == b'skip_thought_signature_validator'
+
+
+def test_skip_thought_signature_validator_assignable_to_part():
+  part = types.Part(
+      text='injected',
+      thought_signature=SKIP_THOUGHT_SIGNATURE_VALIDATOR,
+  )
+  assert part.thought_signature == SKIP_THOUGHT_SIGNATURE_VALIDATOR
+
+
+def test_to_user_content_str_input_becomes_user_text():
+  content = to_user_content('hello')
+  assert content.role == 'user'
+  assert content.parts[0].text == 'hello'
+
+
+def test_to_user_content_input_is_normalized_to_user_role():
+  original = types.Content(role='model', parts=[types.Part(text='hi')])
+  content = to_user_content(original)
+  assert content.role == 'user'
+  assert content.parts[0].text == 'hi'
+
+
+def test_to_user_content_basemodel_input_is_json():
+  class _M(BaseModel):
+    a: int
+
+  content = to_user_content(_M(a=1))
+  assert content.role == 'user'
+  assert '"a":1' in content.parts[0].text.replace(' ', '')
+
+
+def test_to_user_content_dict_input_is_json():
+  content = to_user_content({'a': 1})
+  assert content.role == 'user'
+  assert content.parts[0].text.replace(' ', '') == '{"a":1}'
+
+
+def test_to_user_content_other_input_is_str():
+  content = to_user_content(42)
+  assert content.role == 'user'
+  assert content.parts[0].text == '42'