Refactor test as reusable components

tests/scans/test_data_watch.py

@@ -6,6 +6,7 @@
 # Distributed under the GNU LGPLv3. See LICENSE for more info.
 
 import gevent
+import contextlib
 import gevent.event
 import numpy
 from bliss import setup_globals
@@ -25,6 +26,61 @@ from bliss.scanning.group import Sequence
 from bliss.config.streaming import DataStreamReaderStopHandler
 
 
+@pytest.fixture
+def test_observer(mocker):
+    """Helper to check post mortem the events from the scans watcher"""
+    observer = mocker.Mock(spec=ScansObserver)
+
+    def read_scan_info(observer, method_name):
+        call = getattr(observer, method_name).call_args_list[0]
+        scan_info = call[0][1]
+        return scan_info
+
+    def read_scalar_data(observer, channel_name, scan_db_name):
+        data = []
+        for call_args in observer.on_scalar_data_received.call_args_list:
+            kwargs = call_args[1]
+            if channel_name is not None and kwargs["channel_name"] != channel_name:
+                continue
+            if scan_db_name is not None and kwargs["scan_db_name"] != scan_db_name:
+                continue
+            data.append(kwargs["data_bunch"])
+        if len(data) == 0:
+            return []
+        return numpy.concatenate(data)
+
+    observer.on_scan_created__scan_info = lambda: read_scan_info(
+        observer, "on_scan_created"
+    )
+    observer.on_scan_started__scan_info = lambda: read_scan_info(
+        observer, "on_scan_started"
+    )
+    observer.on_scan_finished__scan_info = lambda: read_scan_info(
+        observer, "on_scan_finished"
+    )
+    observer.on_scalar_data_received__get_data = lambda channel_name, scan_db_name: read_scalar_data(
+        observer, channel_name, scan_db_name
+    )
+
+    yield observer
+
+
+@contextlib.contextmanager
+def watching(session, observer, exclude_groups=False):
+    watcher = ScansWatcher(session.name)
+    watcher.set_exclude_existing_scans(True)
+    if not exclude_groups:
+        watcher.set_watch_scan_group(True)
+    watcher.set_observer(observer)
+    session_watcher = gevent.spawn(watcher.run)
+    watcher.wait_ready(timeout=3)
+    try:
+        yield watcher
+    finally:
+        gevent.sleep(0.5)
+        session_watcher.kill()
+
+
 def test_simple_continuous_scan_with_session_watcher(session, scan_saving, mocker):
 
     m1 = getattr(setup_globals, "m1")
@@ -446,7 +502,6 @@ def test_scan_groups(default_session, mocker):
     assert len(callbacks.scan_new_callback.call_args_list) == 2
 
 
-def test_scan_observer(session, diode_acq_device_factory, mocker):
     observer = mocker.Mock(spec=ScansObserver)
     watcher = ScansWatcher(session.name)
     watcher.set_exclude_existing_scans(True)
@@ -456,6 +511,9 @@ def test_scan_observer(session, diode_acq_device_factory, mocker):
     session_watcher = gevent.spawn(watcher.run)
     watcher.wait_ready(timeout=3)
 
+def test_scan_observer(
+    session, scan_saving, diode_acq_device_factory, test_observer, mocker
+):
     chain = AcquisitionChain()
     acquisition_device_1, _ = diode_acq_device_factory.get(count_time=0.1, npoints=1)
     master = SoftwareTimerMaster(0.1, npoints=1)
@@ -465,31 +523,27 @@ def test_scan_observer(session, diode_acq_device_factory, mocker):
     meta = {"kind": "foo"}
     acquisition_device_1.fill_meta_at_scan_start = mocker.Mock(return_value=meta)
 
-    try:
+    with watching(session, test_observer):
         scan.run()
-    finally:
-        gevent.sleep(0.5)
-        session_watcher.kill()
 
     # TODO check the order of the received events
-    observer.on_scan_created.assert_called_once()
-    observer.on_scan_started.assert_called_once()
-    observer.on_scan_finished.assert_called_once()
+    test_observer.on_scan_created.assert_called_once()
+    test_observer.on_scan_started.assert_called_once()
+    test_observer.on_scan_finished.assert_called_once()
 
     # Check that the scan_info looks like what it is expected
     sf = ScanInfo()
     device_key = sf._get_key_from_acq_obj(acquisition_device_1)
 
-    call = observer.on_scan_created.call_args_list[0]
-    scan_info = call[0][1]
+    scan_info = test_observer.on_scan_created__scan_info()
+    assert scan_info["session_name"] == scan_saving.session
+    assert scan_info["user_name"] == scan_saving.user_name
     assert "positioners_start" in scan_info["positioners"]
     assert "start_timestamp" in scan_info
 
-    call = observer.on_scan_started.call_args_list[0]
-    scan_info = call[0][1]
+    scan_info = test_observer.on_scan_started__scan_info()
     assert "kind" in scan_info["devices"][device_key]
 
-    call = observer.on_scan_finished.call_args_list[0]
-    scan_info = call[0][1]
+    scan_info = test_observer.on_scan_finished__scan_info()
     assert "end_timestamp" in scan_info
     assert "positioners_end" in scan_info["positioners"]