Update many_independent_leaves test

distributed/tests/test_scheduler.py

@@ -100,14 +100,16 @@ async def test_recompute_released_results(c, s, a, b):
     assert result == 1
 
 
-@gen_cluster(client=True)
+@gen_cluster(client=True, config={"distributed.scheduler.bandwidth": "1mb"})
 async def test_decide_worker_with_many_independent_leaves(c, s, a, b):
+    # Make data large to penalize scheduling dependent tasks on other workers
+    ballast = b"\0" * int(s.bandwidth)
     xs = await asyncio.gather(
-        c.scatter(list(range(0, 100, 2)), workers=a.address),
-        c.scatter(list(range(1, 100, 2)), workers=b.address),
+        c.scatter([bytes(i) + ballast for i in range(0, 100, 2)], workers=a.address),
+        c.scatter([bytes(i) + ballast for i in range(1, 100, 2)], workers=b.address),
     )
     xs = list(concat(zip(*xs)))
-    ys = [delayed(inc)(x) for x in xs]
+    ys = [delayed(lambda s: s[0])(x) for x in xs]
 
     y2s = c.persist(ys)
     await wait(y2s)