test that nested experimental KubeClusters can be run on the same eve…

…nt loop

dask_kubernetes/experimental/tests/test_kubecluster.py

@@ -39,6 +39,17 @@ def test_multiple_clusters_simultaneously(kopf_runner, docker_image):
                 assert client2.submit(lambda x: x + 1, 10).result() == 11
 
 
+def test_multiple_clusters_simultaneously_same_loop(kopf_runner, docker_image):
+    with kopf_runner:
+        with KubeCluster(name="fizz", image=docker_image) as cluster1, KubeCluster(
+            name="buzz", image=docker_image, loop=cluster1.loop
+        ) as cluster2:
+            with Client(cluster1) as client1, Client(cluster2) as client2:
+                assert cluster1.loop is cluster2.loop is client1.loop is client2.loop
+                assert client1.submit(lambda x: x + 1, 10).result() == 11
+                assert client2.submit(lambda x: x + 1, 10).result() == 11
+
+
 def test_cluster_from_name(kopf_runner, docker_image):
     with kopf_runner:
         with KubeCluster(name="abc", image=docker_image) as firstcluster: