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/tools/test_wait_tool.py

@@ -0,0 +1,114 @@
+# 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 asyncio
+import time
+from unittest.mock import AsyncMock, MagicMock
+
+from artemis.context import ArtemisContext
+from artemis.tools.base import ArtemisTool, ToolRegistry
+from artemis.tools.wait_tool import (
+    Wait,
+    WaitArgs,
+    WaitTool,
+    get_wait_tool,
+    wait,
+    wait_wrapper,
+)
+import pytest
+
+
+@pytest.fixture
+def mock_ctx():
+    ctx = MagicMock(spec=ArtemisContext)
+    return ctx
+
+
+def test_wait_tool_subclass_and_registry():
+    """Verify WaitTool is a subclass of ArtemisTool and properly registered."""
+    assert issubclass(WaitTool, ArtemisTool)
+    assert issubclass(Wait, ArtemisTool)
+    assert isinstance(wait, ArtemisTool)
+    assert isinstance(wait, WaitTool)
+
+    assert wait.name == "wait"
+    assert wait.category == "system"
+    assert wait.args_schema == WaitArgs
+
+    # Registry lookup
+    reg_tool = ToolRegistry.get("wait")
+    assert reg_tool is not None
+    assert isinstance(reg_tool, WaitTool)
+
+    # GenAI FunctionDeclaration export
+    declaration = wait.to_genai_declaration()
+    assert declaration.name == "wait"
+    assert "seconds" in declaration.parameters.properties
+
+    # Wrapper check
+    assert wait_wrapper is not None
+    assert wait_wrapper.tool_fn_getter == get_wait_tool
+
+
+@pytest.mark.asyncio
+async def test_wait_direct_execution(mock_ctx):
+    """Verify direct execution of WaitTool.execute."""
+    with pytest.MonkeyPatch.context() as mp:
+        mock_sleep = AsyncMock()
+        mp.setattr(asyncio, "sleep", mock_sleep)
+
+        result = await wait.execute(ctx=mock_ctx, seconds=5)
+        mock_sleep.assert_called_once_with(5)
+        assert result == "Successfully waited for 5 seconds."
+
+
+@pytest.mark.asyncio
+async def test_wait_callable_execution(mock_ctx):
+    """Verify invoking wait directly as a callable."""
+    with pytest.MonkeyPatch.context() as mp:
+        mock_sleep = AsyncMock()
+        mp.setattr(asyncio, "sleep", mock_sleep)
+
+        result = await wait(ctx=mock_ctx, seconds=3)
+        mock_sleep.assert_called_once_with(3)
+        assert result == "Successfully waited for 3 seconds."
+
+
+@pytest.mark.asyncio
+async def test_wait_tool(mock_ctx):
+    wait_tool = get_wait_tool(mock_ctx)
+
+    start_time = time.time()
+    result = await wait_tool.ainvoke({"seconds": 2})
+    end_time = time.time()
+
+    duration = end_time - start_time
+    assert duration >= 1.9  # Allow slight timing variations
+    assert "Successfully waited for 2 seconds" in result
+
+
+@pytest.mark.asyncio
+async def test_wait_tool_bounds(mock_ctx):
+    wait_tool = get_wait_tool(mock_ctx)
+
+    with pytest.MonkeyPatch.context() as mp:
+        mock_sleep = AsyncMock()
+        mp.setattr(asyncio, "sleep", mock_sleep)
+
+        await wait_tool.ainvoke({"seconds": 120})
+        mock_sleep.assert_called_once_with(60)
+
+        mock_sleep.reset_mock()
+        await wait_tool.ainvoke({"seconds": -5})
+        mock_sleep.assert_called_once_with(1)