Moves unittests to root folder and adds github action to run unit tests. (#72)

* Move unit tests to root package.

* Adds deps to "test" extra, and mark two broken tests in tests/unittests/auth/test_auth_handler.py

* Adds github workflow

* minor fix in lite_llm.py for python 3.9.

* format pyproject.toml

tests/unittests/tools/test_base_tool.py

@@ -0,0 +1,141 @@
+# Copyright 2025 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 typing import Optional
+
+from google.adk.agents.invocation_context import InvocationContext
+from google.adk.agents.sequential_agent import SequentialAgent
+from google.adk.models.llm_request import LlmRequest
+from google.adk.sessions.in_memory_session_service import InMemorySessionService
+from google.adk.tools.base_tool import BaseTool
+from google.adk.tools.tool_context import ToolContext
+from google.genai import types
+import pytest
+
+
+class _TestingTool(BaseTool):
+
+  def __init__(
+      self,
+      declaration: Optional[types.FunctionDeclaration] = None,
+  ):
+    super().__init__(name='test_tool', description='test_description')
+    self.declaration = declaration
+
+  def _get_declaration(self) -> Optional[types.FunctionDeclaration]:
+    return self.declaration
+
+
+def _create_tool_context() -> ToolContext:
+  session_service = InMemorySessionService()
+  session = session_service.create_session(
+      app_name='test_app', user_id='test_user'
+  )
+  agent = SequentialAgent(name='test_agent')
+  invocation_context = InvocationContext(
+      invocation_id='invocation_id',
+      agent=agent,
+      session=session,
+      session_service=session_service,
+  )
+  return ToolContext(invocation_context)
+
+
+@pytest.mark.asyncio
+async def test_process_llm_request_no_declaration():
+  tool = _TestingTool()
+  tool_context = _create_tool_context()
+  llm_request = LlmRequest()
+
+  await tool.process_llm_request(
+      tool_context=tool_context, llm_request=llm_request
+  )
+
+  assert llm_request.config is None
+
+
+@pytest.mark.asyncio
+async def test_process_llm_request_with_declaration():
+  declaration = types.FunctionDeclaration(
+      name='test_tool',
+      description='test_description',
+      parameters=types.Schema(
+          type=types.Type.STRING,
+          title='param_1',
+      ),
+  )
+  tool = _TestingTool(declaration)
+  llm_request = LlmRequest()
+  tool_context = _create_tool_context()
+
+  await tool.process_llm_request(
+      tool_context=tool_context, llm_request=llm_request
+  )
+
+  assert llm_request.config.tools[0].function_declarations == [declaration]
+
+
+@pytest.mark.asyncio
+async def test_process_llm_request_with_builtin_tool():
+  declaration = types.FunctionDeclaration(
+      name='test_tool',
+      description='test_description',
+      parameters=types.Schema(
+          type=types.Type.STRING,
+          title='param_1',
+      ),
+  )
+  tool = _TestingTool(declaration)
+  llm_request = LlmRequest(
+      config=types.GenerateContentConfig(
+          tools=[types.Tool(google_search=types.GoogleSearch())]
+      )
+  )
+  tool_context = _create_tool_context()
+
+  await tool.process_llm_request(
+      tool_context=tool_context, llm_request=llm_request
+  )
+
+  # function_declaration is added to another types.Tool without builtin tool.
+  assert llm_request.config.tools[1].function_declarations == [declaration]
+
+
+@pytest.mark.asyncio
+async def test_process_llm_request_with_builtin_tool_and_another_declaration():
+  declaration = types.FunctionDeclaration(
+      name='test_tool',
+      description='test_description',
+      parameters=types.Schema(
+          type=types.Type.STRING,
+          title='param_1',
+      ),
+  )
+  tool = _TestingTool(declaration)
+  llm_request = LlmRequest(
+      config=types.GenerateContentConfig(
+          tools=[
+              types.Tool(google_search=types.GoogleSearch()),
+              types.Tool(function_declarations=[types.FunctionDeclaration()]),
+          ]
+      )
+  )
+  tool_context = _create_tool_context()
+
+  await tool.process_llm_request(
+      tool_context=tool_context, llm_request=llm_request
+  )
+
+  # function_declaration is added to existing types.Tool with function_declaration.
+  assert llm_request.config.tools[1].function_declarations[1] == declaration