diff --git a/metropolis/node/core/consensus/consensus_test.go b/metropolis/node/core/consensus/consensus_test.go
index 2671432..77ea63b 100644
--- a/metropolis/node/core/consensus/consensus_test.go
+++ b/metropolis/node/core/consensus/consensus_test.go
@@ -93,7 +93,7 @@
 		externalHost: "127.0.0.1",
 	})
 
-	supervisor.New(b.ctx, etcd.Run)
+	supervisor.TestHarness(t, etcd.Run)
 	waitEtcd(t, etcd)
 
 	kv := etcd.Client()
@@ -116,7 +116,7 @@
 		Port:         freeport.MustConsume(freeport.AllocateTCPPort()),
 		externalHost: "127.0.0.1",
 	})
-	supervisor.New(b.ctx, etcd.Run)
+	supervisor.TestHarness(t, etcd.Run)
 	waitEtcd(t, etcd)
 
 	id, name, err := etcd.MemberInfo(b.ctx)
@@ -159,9 +159,9 @@
 			Port:         freeport.MustConsume(freeport.AllocateTCPPort()),
 			externalHost: "127.0.0.1",
 		})
-		ctx, ctxC := context.WithCancel(b.ctx)
-		supervisor.New(ctx, etcd.Run)
+		ctxC, _ := supervisor.TestHarness(t, etcd.Run)
 		waitEtcd(t, etcd)
+
 		kv := etcd.Client()
 		if new {
 			if _, err := kv.Put(b.ctx, "/foo", "bar"); err != nil {
@@ -203,7 +203,7 @@
 		Port:         freeport.MustConsume(freeport.AllocateTCPPort()),
 		externalHost: "127.0.0.1",
 	})
-	supervisor.New(b.ctx, etcd.Run)
+	supervisor.TestHarness(t, etcd.Run)
 	waitEtcd(t, etcd)
 
 	etcd.stateMu.Lock()
diff --git a/metropolis/node/core/curator/curator_test.go b/metropolis/node/core/curator/curator_test.go
index 6ce489d..14c705a 100644
--- a/metropolis/node/core/curator/curator_test.go
+++ b/metropolis/node/core/curator/curator_test.go
@@ -221,7 +221,7 @@
 
 	// Start a new supervisor in which we create all curator DUTs.
 	dutC := make(chan *dut)
-	supervisor.New(ctx, func(ctx context.Context) error {
+	supervisor.TestHarness(t, func(ctx context.Context) error {
 		for e, _ := range endpointToNum {
 			dutC <- newDut(ctx, t, e)
 		}
diff --git a/metropolis/node/core/curator/listener_test.go b/metropolis/node/core/curator/listener_test.go
index 0739d84..7e998da 100644
--- a/metropolis/node/core/curator/listener_test.go
+++ b/metropolis/node/core/curator/listener_test.go
@@ -54,15 +54,17 @@
 	}
 
 	// Start listener under supervisor.
-	ctx, ctxC := context.WithCancel(context.Background())
-	defer ctxC()
-	supervisor.New(ctx, l.run)
+	supervisor.TestHarness(t, l.run)
 
 	// Begin with a follower.
 	val.Set(electionStatus{
 		follower: &electionStatusFollower{},
 	})
 
+	// Context for this test.
+	ctx, ctxC := context.WithCancel(context.Background())
+	defer ctxC()
+
 	// Simulate a request context.
 	ctxR, ctxRC := context.WithCancel(ctx)