added capture time for every sweep

python_app/tests/test_switched_matrix_capture.py

@@ -140,6 +140,36 @@ class SwitchedMatrixComboAcquisitionTest(unittest.TestCase):
             expected_combos,
         )
 
+    def test_each_switch_step_stamps_its_traces_with_its_own_capture_window(self) -> None:
+        # The whole point of per-trace timing: three switch steps are measured one
+        # after another, so their traces must NOT all share the collection window.
+        service, _inner, _input_switch = _switched_service(input_steps=3)
+
+        collection = service.acquire_collection(collection_id=7)
+
+        windows_by_step: dict[int, set[tuple[int, int]]] = {}
+        for trace in collection.traces:
+            step = int(trace.combo.input) // _INNER_INPUTS
+            windows_by_step.setdefault(step, set()).add(
+                (int(trace.capture_start_ns), int(trace.capture_end_ns))
+            )
+
+        self.assertEqual(sorted(windows_by_step), [0, 1, 2])
+        for step, windows in windows_by_step.items():
+            self.assertEqual(len(windows), 1, f"step {step} traces disagree on their window")
+            start_ns, end_ns = next(iter(windows))
+            self.assertGreater(start_ns, 0)
+            self.assertGreaterEqual(end_ns, start_ns)
+            # Each step's window sits inside the collection's.
+            self.assertGreaterEqual(start_ns, collection.capture_start_ns)
+            self.assertLessEqual(end_ns, collection.capture_end_ns)
+
+        # Steps are strictly ordered in time — the whole reason the collection-level
+        # window cannot stand in for a per-combo timestamp.
+        step_starts = [next(iter(windows_by_step[step]))[0] for step in sorted(windows_by_step)]
+        self.assertEqual(step_starts, sorted(step_starts))
+        self.assertGreater(len(set(step_starts)), 1)
+
 
 class ManualComboCaptureUsesTargetedAcquisitionTest(unittest.TestCase):
     """The per-combo capture session must not sweep the full widened matrix."""