SERVER-58576 Improve build variant task gen unit tests

2 files changed, 5 insertions, 3 deletions

diff --git a/buildscripts/evergreen_gen_build_variant.py b/buildscripts/evergreen_gen_build_variant.py
index 4bf805d0122..65597d5aa4d 100644
--- a/buildscripts/evergreen_gen_build_variant.py
+++ b/buildscripts/evergreen_gen_build_variant.py
@@ -389,7 +389,7 @@ class GenerateBuildVariantOrchestrator:
         LOGGER.info("Configure task", task_id=task.task_id, priority=priority)
         self.evg_api.configure_task(task.task_id, priority=priority)
 
-    def adjust_gen_tasks_priority(self, gen_tasks: Set[str]) -> None:
+    def adjust_gen_tasks_priority(self, gen_tasks: Set[str]) -> int:
         """
         Increase the priority of any "_gen" tasks.
 
@@ -407,7 +407,8 @@ class GenerateBuildVariantOrchestrator:
                 if task.display_name in gen_tasks
             ]
 
-        [j.result() for j in jobs]  # pylint: disable=expression-not-assigned
+        results = [j.result() for j in jobs]
+        return len(results)
 
 
 @click.command()
diff --git a/buildscripts/tests/test_evergreen_gen_build_variant.py b/buildscripts/tests/test_evergreen_gen_build_variant.py
index a2fa41bd5db..e14689a3169 100644
--- a/buildscripts/tests/test_evergreen_gen_build_variant.py
+++ b/buildscripts/tests/test_evergreen_gen_build_variant.py
@@ -300,6 +300,7 @@ class TestAdjustGenTasksPriority(unittest.TestCase):
         ]
         mock_orchestrator = build_mock_orchestrator(build_task_list=mock_task_list)
 
-        mock_orchestrator.adjust_gen_tasks_priority(gen_tasks)
+        n_tasks_adjusted = mock_orchestrator.adjust_gen_tasks_priority(gen_tasks)
 
+        self.assertEqual(len(gen_tasks), n_tasks_adjusted)
         self.assertEqual(len(gen_tasks), mock_orchestrator.evg_api.configure_task.call_count)