Create testing fixtures

tests/component/conftest.py

@@ -0,0 +1,77 @@
+# SPDX-License-Identifier: BSD-3-Clause
+# Copyright (c) 2026 Nutanix, Inc. All rights reserved.
+#
+# Author: Leonardo Forchini <leonardo.forchini@nutanix.com>
+
+"""Fixtures for the local component-test harness."""
+
+import pytest
+
+from harness.common import POLL_S, built_binary
+from harness.controller import Controller
+from harness.dbus import DBusServer
+from harness.fake_backend import FakeBackend
+from harness.mockfs import MockProc
+
+
+@pytest.fixture
+def fake_backend(tmp_path):
+    return FakeBackend(tmp_path)
+
+
+@pytest.fixture
+def dbus_server(tmp_path):
+    server = DBusServer(tmp_path)
+    server.start()
+    yield server
+    server.stop()
+
+
+@pytest.fixture
+def mock_proc(tmp_path, dbus_server):
+    proc = MockProc(tmp_path, built_binary("mockfsd"), dbus_server)
+    yield proc
+    proc.stop()
+
+
+@pytest.fixture
+def controller(tmp_path, fake_backend, dbus_server):
+    del fake_backend  # created first so the state directory exists
+    launched = Controller(tmp_path, built_binary("io-thread-controller"), dbus_server)
+    yield launched
+    launched.stop()
+
+
+@pytest.fixture
+def fast_threshold():
+    """Decisions land on the next eligible poll, with validation disabled."""
+    return {
+        "scale_up_threshold_percent": 60,
+        "scale_down_sustain_polls": 1,
+        "max_scale_down_step": 1,
+        "scale_up_min_gain_percent": 0,
+        "scale_down_revert_drop_percent": 0,
+        "scale_validation_sample_polls": 0,
+    }
+
+
+@pytest.fixture
+def run_threshold(controller):
+    """Start the daemon on the threshold engine with open controller bounds."""
+
+    def start(engine_config, **overrides):
+        settings = {
+            "scale_poll_secs": POLL_S,
+            "min_thread_count": 1,
+            "max_thread_count": 8,
+            "host_cpu_scale_up_ceiling_percent": 0,
+            "cooldown_secs": 0,
+        }
+        settings.update(overrides)
+        controller(
+            engine="threshold",
+            engine_config=engine_config,
+            controller_overrides=settings,
+        )
+
+    return start