test: add comprehensive unit, integration, and e2e test suites

Introduce complete test coverage for the ARTEMIS platform across multiple layers:
Unit tests: Add tests for agent nodes (Planner, Operator, Validator, Diagnoser, FlashRunner, Explorer), tools, utils (OCR/XML fusion, UI hierarchy), and data engine.
Integration tests: Add live tool verification, reactive runner, IME, and standalone workflow tests.
E2E tests: Add end-to-end scenario tests for media playback and failure recovery flows.
Fixtures & mocks: Add mock inputs (audio, video, screenshot) and test utilities.

tests/tools/video_analyzer/test_video_analyzer_tools.py

@@ -0,0 +1,103 @@
+# 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 pathlib import Path
+from unittest.mock import MagicMock, patch
+
+import pytest
+from artemis.agents.video_analyzer.video_analyzer import VideoAnalyzer
+
+
+@pytest.mark.asyncio
+async def test_video_analyzer_tools(artemis_context, mock_state, inputs_dir):
+    artemis_context.device.mobile_platform = "android"
+    artemis_context.adb_client = artemis_context.ui_adb_client
+
+    agent = VideoAnalyzer(ctx=artemis_context)
+
+    agent.local_files_to_cleanup = set()
+    agent.local_dirs_to_cleanup = set()
+    agent.cloud_files_to_cleanup = set()
+    agent.blackboard_entries = []
+    agent.sub_system_prompt = "You are a sub agent"
+    agent.audio_system_prompt = "You are an audio sub agent"
+    agent.model_name = "gemini-3.6-flash"
+
+    # We must provide a valid FunctionDeclaration for the tool otherwise Pydantic will complain
+    from google.genai import types
+
+    agent.submit_answer_tool = types.FunctionDeclaration(
+        name="submit_answer",
+        description=("Submit the final findings for the requested segment analysis."),
+        parameters=types.Schema(
+            type=types.Type.OBJECT,
+            properties={
+                "summary": types.Schema(type=types.Type.STRING, description="summary"),
+                "analysis": types.Schema(type=types.Type.STRING, description="analysis"),
+                "timeline_events": types.Schema(
+                    type=types.Type.ARRAY,
+                    items=types.Schema(
+                        type=types.Type.OBJECT,
+                        properties={
+                            "start_time": types.Schema(type=types.Type.NUMBER),
+                            "end_time": types.Schema(type=types.Type.NUMBER),
+                            "transcription": types.Schema(type=types.Type.STRING),
+                            "confidence_score": types.Schema(type=types.Type.NUMBER),
+                            "verification_timestamp_secs": types.Schema(type=types.Type.NUMBER),
+                        },
+                    ),
+                ),
+            },
+        ),
+    )
+
+    import google.genai as genai
+    from artemis.config import settings
+
+    agent.client = genai.Client(
+        api_key=settings.GOOGLE_API_KEY.get_secret_value() if settings.GOOGLE_API_KEY else None
+    )
+    artemis_context._genai_client = agent.client
+
+    mock_session = MagicMock()
+    mock_session.local_video_path = Path(inputs_dir) / "recording.mp4"
+    mock_session.start_time = 0.0
+    mock_session.data_engine_start_time = None
+    mock_session.process = MagicMock()
+    mock_session.process.returncode = None
+    mock_session.android_video_segments = []
+    mock_session.android_segment_index = 0
+
+    from unittest.mock import AsyncMock
+
+    sample_video = Path(inputs_dir) / "recording.mp4"
+    mock_driver = MagicMock()
+    mock_driver.stop_video_recording = AsyncMock(return_value=sample_video)
+    artemis_context._active_driver = mock_driver
+
+    with patch(
+        "artemis.controllers.android_controller.get_active_session",
+        return_value=mock_session,
+    ):
+        result = await agent.exec_extract_segment_metadata(start_time=0.0, end_time=1.0)
+        assert isinstance(result, str)
+        assert len(result) > 0
+
+        # Test sub-agent with extremely short audio query to not waste resources and time
+        audio_result = await agent.exec_analyze_audio_only(
+            start_time=0.0,
+            end_time=1.0,
+            specific_query="Reply with a short summary only.",
+        )
+        assert isinstance(audio_result, str)