diff --git a/tests/test_api_images.py b/tests/test_api_images.py
index f9357f94..7c561f1f 100644
--- a/tests/test_api_images.py
+++ b/tests/test_api_images.py
@@ -2431,6 +2431,9 @@ class TestSharedListing(ImageAPITestCase):
         async def settle():
             while self.api._listing_tasks:
                 await asyncio.gather(*list(self.api._listing_tasks))
+                # A finished walk leaves the set in a done callback, which needs
+                # a loop turn; gather over finished tasks does not yield one.
+                await asyncio.sleep(0)
 
         await asyncio.wait_for(settle(), _HANG_LIMIT)
 
diff --git a/tests/test_api_workspace_images.py b/tests/test_api_workspace_images.py
index cd8fe396..dceae1f6 100644
--- a/tests/test_api_workspace_images.py
+++ b/tests/test_api_workspace_images.py
@@ -196,6 +196,9 @@ class TestWorkspaceImages(ImageAPITestCase):
             await self.get()  # served at once; one background walk runs
             while self.api._listing_tasks:
                 await asyncio.gather(*list(self.api._listing_tasks))
+                # A finished walk leaves the set in a done callback, which needs
+                # a loop turn; gather over finished tasks does not yield one.
+                await asyncio.sleep(0)
             _, again = await self.get()
         self.assertEqual(scan.call_count, 1)
         self.assertIs(record.files, files)