chore: import upstream snapshot with attribution

tests/unittests/utils/test_yaml_utils.py

@@ -0,0 +1,154 @@
+# 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.
+
+"""Tests for YAML utility functions."""
+
+from pathlib import Path
+from typing import Optional
+
+from google.adk.utils.yaml_utils import dump_pydantic_to_yaml
+from google.genai import types
+from pydantic import BaseModel
+
+
+class SimpleModel(BaseModel):
+  """Simple test model."""
+
+  name: str
+  age: int
+  active: bool
+  finish_reason: Optional[types.FinishReason] = None
+  multiline_text: Optional[str] = None
+  items: Optional[list[str]] = None
+
+
+def test_yaml_file_generation(tmp_path: Path):
+  """Test that YAML file is correctly generated."""
+  model = SimpleModel(
+      name="Alice",
+      age=30,
+      active=True,
+      finish_reason=types.FinishReason.STOP,
+  )
+  yaml_file = tmp_path / "test.yaml"
+
+  dump_pydantic_to_yaml(model, yaml_file)
+
+  assert yaml_file.read_text(encoding="utf-8") == """\
+active: true
+age: 30
+finish_reason: STOP
+name: Alice
+"""
+
+
+def test_multiline_string_pipe_style(tmp_path: Path):
+  """Test that multiline strings use | style."""
+  multiline_text = """\
+This is a long description
+that spans multiple lines
+and should be formatted with pipe style"""
+  model = SimpleModel(
+      name="Test",
+      age=25,
+      active=False,
+      multiline_text=multiline_text,
+  )
+  yaml_file = tmp_path / "test.yaml"
+
+  dump_pydantic_to_yaml(model, yaml_file)
+
+  assert yaml_file.read_text(encoding="utf-8") == """\
+active: false
+age: 25
+multiline_text: |-
+  This is a long description
+  that spans multiple lines
+  and should be formatted with pipe style
+name: Test
+"""
+
+
+def test_list_indentation(tmp_path: Path):
+  """Test that lists in mappings are properly indented."""
+  model = SimpleModel(
+      name="Test",
+      age=25,
+      active=True,
+      items=["item1", "item2", "item3"],
+  )
+  yaml_file = tmp_path / "test.yaml"
+
+  dump_pydantic_to_yaml(model, yaml_file)
+
+  expected = """\
+active: true
+age: 25
+items:
+  - item1
+  - item2
+  - item3
+name: Test
+"""
+  assert yaml_file.read_text(encoding="utf-8") == expected
+
+
+def test_empty_list_formatting(tmp_path: Path):
+  """Test that empty lists are formatted properly."""
+  model = SimpleModel(
+      name="Test",
+      age=25,
+      active=True,
+      items=[],
+  )
+  yaml_file = tmp_path / "test.yaml"
+
+  dump_pydantic_to_yaml(model, yaml_file)
+
+  expected = """\
+active: true
+age: 25
+items: []
+name: Test
+"""
+  assert yaml_file.read_text(encoding="utf-8") == expected
+
+
+def test_non_ascii_character_preservation(tmp_path: Path):
+  """Test that non-ASCII characters are preserved in YAML output."""
+  model = SimpleModel(
+      name="你好世界",  # Chinese
+      age=30,
+      active=True,
+      multiline_text="🌍 Hello World 🌏\nこんにちは世界\nHola Mundo 🌎",
+      items=["Château", "naïve", "café", "🎉"],
+  )
+  yaml_file = tmp_path / "test.yaml"
+
+  dump_pydantic_to_yaml(model, yaml_file)
+
+  assert yaml_file.read_text(encoding="utf-8") == """\
+active: true
+age: 30
+items:
+  - Château
+  - naïve
+  - café
+  - 🎉
+multiline_text: |-
+  🌍 Hello World 🌏
+  こんにちは世界
+  Hola Mundo 🌎
+name: 你好世界
+"""