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/unit/agents/test_outputter_tools_unit.py

@@ -0,0 +1,102 @@
+# 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.
+
+import json
+from unittest.mock import MagicMock, mock_open, patch
+
+from artemis.agents.outputter.tools import (
+    get_search_history_tool,
+    get_step_details_tool,
+    get_step_screenshot_tool,
+)
+from artemis.context import ArtemisContext
+import pytest
+
+
+@pytest.fixture
+def mock_context():
+    ctx = MagicMock(spec=ArtemisContext)
+    ctx.data_engine = MagicMock()
+    ctx.data_engine.global_base_dir = "/tmp/fake_traces"
+    return ctx
+
+
+def test_get_step_details_tool():
+    steps = [
+        {
+            "step_number": 1,
+            "relative_time": "1s",
+            "summary": "Step 1",
+            "action_taken": "tap",
+        },
+        {
+            "step_number": 2,
+            "relative_time": "2s",
+            "summary": "Step 2",
+            "action_taken": "swipe",
+        },
+    ]
+    tool = get_step_details_tool(steps)
+
+    # Test valid range
+    result = tool.invoke({"start_step": 1, "end_step": 1})
+    parsed = json.loads(result)
+    assert len(parsed) == 1
+    assert parsed[0]["step_number"] == 1
+    assert parsed[0]["action_taken"] == "tap"
+
+    # Test invalid range
+    result_invalid = tool.invoke({"start_step": 3, "end_step": 4})
+    assert "No steps found" in result_invalid
+
+
+def test_get_step_screenshot_tool(mock_context):
+    steps = [
+        {"step_number": 1, "pre_image_name": "img1", "post_image_name": "img2"},
+    ]
+    tool = get_step_screenshot_tool(mock_context, steps)
+
+    # Mock open and exists
+    with (
+        patch("pathlib.Path.exists", return_value=True),
+        patch("builtins.open", mock_open(read_data=b"fake_image_bytes")),
+    ):
+        result = tool.invoke({"step_number": 1})
+        assert isinstance(result, list)
+        assert result[0]["type"] == "text"
+        assert result[1]["type"] == "image_url"
+        assert "data:image/jpeg;base64" in result[1]["image_url"]["url"]
+
+
+def test_search_history_tool(mock_context):
+    tool = get_search_history_tool(mock_context)
+
+    # Mock steps returned by storage
+    mock_step_1 = MagicMock()
+    mock_step_1.step_number = 1
+    mock_step_1.pre_image_name = "img1"
+    mock_step_1.post_image_name = None
+
+    mock_context.data_engine.storage.get_steps.return_value = [mock_step_1]
+
+    # Mock search_ui_by_hash
+    mock_context.data_engine.storage.search_ui_by_hash.return_value = [
+        {"type": "ocr", "matched_text": "verification code: 1234", "score": 0.9}
+    ]
+
+    result = tool.invoke({"query": "verification"})
+    parsed = json.loads(result)
+    assert len(parsed) == 1
+    assert parsed[0]["step_number"] == 1
+    assert parsed[0]["matches"][0]["matched_text"] == "verification code: 1234"