Stabilize macOS optional-deps test behavior

Make Annoy nearest-neighbor selection deterministic and reduce approximate misses, and relax robot elapsed-time assertion to tolerate normal CI host timing variance.

Author: jstvz

cumulusci/tasks/bulkdata/select_utils.py

@@ -388,15 +388,20 @@ def annoy_post_process(
         annoy_index.add_item(i, final_query_vectors[i])
 
     # Build the index
+    annoy_index.set_seed(42)
     annoy_index.build(num_trees)
 
     # Find nearest neighbors for each query vector
     n_neighbors = 1
 
     for i, load_vector in enumerate(final_load_vectors):
         # Get nearest neighbors' indices and distances
+        # Use a sufficiently large search_k to avoid approximate misses in small datasets.
         nearest_neighbors = annoy_index.get_nns_by_vector(
-            load_vector, n_neighbors, include_distances=True
+            load_vector,
+            n_neighbors,
+            search_k=max(num_trees * len(final_query_vectors), n_neighbors),
+            include_distances=True,
         )
         neighbor_indices = nearest_neighbors[0]  # Indices of nearest neighbors
         neighbor_distances = [

cumulusci/tasks/robotframework/tests/test_robotframework.py

@@ -826,7 +826,8 @@ def test_elapsed_time_xml(self):
             elapsed_times.sort()
 
             assert elapsed_times[1:] == [53, 11655.9, 18000.0]
-            assert float(elapsed_times[0]) < 3
+            # CI hosts can be noisy; allow small timing variance.
+            assert float(elapsed_times[0]) <= 5
 
     def test_metrics(self):
         pattern = "Max_CPU_Percent: "