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/agents/test_sequential_agent.py

@@ -0,0 +1,114 @@
+# 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.
+
+"""Testings for the SequentialAgent."""
+
+from typing import AsyncGenerator
+
+from google.adk.agents.base_agent import BaseAgent
+from google.adk.agents.invocation_context import InvocationContext
+from google.adk.agents.sequential_agent import SequentialAgent
+from google.adk.events import Event
+from google.adk.sessions.in_memory_session_service import InMemorySessionService
+from google.genai import types
+import pytest
+from typing_extensions import override
+
+
+class _TestingAgent(BaseAgent):
+
+  @override
+  async def _run_async_impl(
+      self, ctx: InvocationContext
+  ) -> AsyncGenerator[Event, None]:
+    yield Event(
+        author=self.name,
+        invocation_id=ctx.invocation_id,
+        content=types.Content(
+            parts=[types.Part(text=f'Hello, async {self.name}!')]
+        ),
+    )
+
+  @override
+  async def _run_live_impl(
+      self, ctx: InvocationContext
+  ) -> AsyncGenerator[Event, None]:
+    yield Event(
+        author=self.name,
+        invocation_id=ctx.invocation_id,
+        content=types.Content(
+            parts=[types.Part(text=f'Hello, live {self.name}!')]
+        ),
+    )
+
+
+def _create_parent_invocation_context(
+    test_name: str, agent: BaseAgent
+) -> InvocationContext:
+  session_service = InMemorySessionService()
+  session = session_service.create_session(
+      app_name='test_app', user_id='test_user'
+  )
+  return InvocationContext(
+      invocation_id=f'{test_name}_invocation_id',
+      agent=agent,
+      session=session,
+      session_service=session_service,
+  )
+
+
+@pytest.mark.asyncio
+async def test_run_async(request: pytest.FixtureRequest):
+  agent_1 = _TestingAgent(name=f'{request.function.__name__}_test_agent_1')
+  agent_2 = _TestingAgent(name=f'{request.function.__name__}_test_agent_2')
+  sequential_agent = SequentialAgent(
+      name=f'{request.function.__name__}_test_agent',
+      sub_agents=[
+          agent_1,
+          agent_2,
+      ],
+  )
+  parent_ctx = _create_parent_invocation_context(
+      request.function.__name__, sequential_agent
+  )
+  events = [e async for e in sequential_agent.run_async(parent_ctx)]
+
+  assert len(events) == 2
+  assert events[0].author == agent_1.name
+  assert events[1].author == agent_2.name
+  assert events[0].content.parts[0].text == f'Hello, async {agent_1.name}!'
+  assert events[1].content.parts[0].text == f'Hello, async {agent_2.name}!'
+
+
+@pytest.mark.asyncio
+async def test_run_live(request: pytest.FixtureRequest):
+  agent_1 = _TestingAgent(name=f'{request.function.__name__}_test_agent_1')
+  agent_2 = _TestingAgent(name=f'{request.function.__name__}_test_agent_2')
+  sequential_agent = SequentialAgent(
+      name=f'{request.function.__name__}_test_agent',
+      sub_agents=[
+          agent_1,
+          agent_2,
+      ],
+  )
+  parent_ctx = _create_parent_invocation_context(
+      request.function.__name__, sequential_agent
+  )
+  events = [e async for e in sequential_agent.run_live(parent_ctx)]
+
+  assert len(events) == 2
+  assert events[0].author == agent_1.name
+  assert events[1].author == agent_2.name
+  assert events[0].content.parts[0].text == f'Hello, live {agent_1.name}!'
+  assert events[1].content.parts[0].text == f'Hello, live {agent_2.name}!'