diff --git a/tests/base.py b/tests/base.py
index b6c8291509..e74980d109 100644
--- a/tests/base.py
+++ b/tests/base.py
@@ -3228,6 +3228,10 @@ class RecordingExecutorServer(zuul.executor.server.ExecutorServer):
         super(RecordingExecutorServer, self).stop()
 
 
+class TestScheduler(zuul.scheduler.Scheduler):
+    _merger_client_class = RecordingMergeClient
+
+
 class FakeGearmanServer(gear.Server):
     """A Gearman server for use in tests.
 
@@ -4020,28 +4024,18 @@ class SchedulerTestApp:
         )
         self.connections.configure(self.config, source_only=source_only)
 
-        self.sched = zuul.scheduler.Scheduler(self.config, self.connections)
+        self.sched = TestScheduler(self.config, self.connections, self)
+        self.sched._stats_interval = 1
+
         if validate_tenants is None:
             self.connections.registerScheduler(self.sched)
 
-        self.sched.setZuulApp(self)
-        self.sched._stats_interval = 1
-
         self.event_queues = [
             self.sched.result_event_queue,
             self.sched.trigger_event_queue,
             self.sched.management_event_queue
         ]
 
-        executor_client = zuul.executor.client.ExecutorClient(
-            self.config, self.sched)
-        merge_client = RecordingMergeClient(self.config, self.sched)
-        nodepool = zuul.nodepool.Nodepool(self.sched)
-
-        self.sched.setExecutor(executor_client)
-        self.sched.setMerger(merge_client)
-        self.sched.setNodepool(nodepool)
-
     def start(self, validate_tenants: list):
         self.sched.start()
         self.sched.executor.gearman.waitForServer()
diff --git a/zuul/cmd/client.py b/zuul/cmd/client.py
index 5c4c096056..0240f8b5ba 100755
--- a/zuul/cmd/client.py
+++ b/zuul/cmd/client.py
@@ -728,7 +728,7 @@ class Client(zuul.cmd.ZuulApp):
         from zuul import configloader
         self.configure_connections(source_only=True)
         sched = scheduler.Scheduler(self.config, self.connections,
-                                    testonly=True)
+                                    self, testonly=True)
         loader = configloader.ConfigLoader(
             sched.connections, sched, None, None)
         tenant_config, script = sched._checkTenantSourceConf(self.config)
diff --git a/zuul/cmd/scheduler.py b/zuul/cmd/scheduler.py
index 89435b39da..d1ec602147 100755
--- a/zuul/cmd/scheduler.py
+++ b/zuul/cmd/scheduler.py
@@ -19,11 +19,8 @@ import sys
 import signal
 
 import zuul.cmd
-import zuul.executor.client
 from zuul.lib.config import get_default
 from zuul.lib.statsd import get_statsd_config
-import zuul.merger.client
-import zuul.nodepool
 import zuul.scheduler
 
 
@@ -139,24 +136,11 @@ class Scheduler(zuul.cmd.ZuulDaemonApp):
         self.log = logging.getLogger("zuul.Scheduler")
 
         self.configure_connections(require_sql=True)
-        self.sched = zuul.scheduler.Scheduler(self.config, self.connections)
+        self.sched = zuul.scheduler.Scheduler(self.config,
+                                              self.connections, self)
         if self.args.validate_tenants is None:
             self.connections.registerScheduler(self.sched)
 
-        self.sched.setZuulApp(self)
-        merger = zuul.merger.client.MergeClient(self.config, self.sched)
-        self.sched.setMerger(merger)
-
-        if self.args.validate_tenants is None:
-
-            # Only needed in full mode
-            gearman = zuul.executor.client.ExecutorClient(self.config,
-                                                          self.sched)
-            nodepool = zuul.nodepool.Nodepool(self.sched)
-
-            self.sched.setExecutor(gearman)
-            self.sched.setNodepool(nodepool)
-
         self.log.info('Starting scheduler')
         try:
             self.sched.start()
diff --git a/zuul/scheduler.py b/zuul/scheduler.py
index 1731106515..ba673ec3a6 100644
--- a/zuul/scheduler.py
+++ b/zuul/scheduler.py
@@ -41,6 +41,9 @@ from zuul.lib.logutil import get_annotated_logger
 from zuul.lib.statsd import get_statsd, normalize_statsd_name
 import zuul.lib.queue
 import zuul.lib.repl
+from zuul import nodepool
+from zuul.executor.client import ExecutorClient
+from zuul.merger.client import MergeClient
 from zuul.model import Build, HoldRequest, Tenant, TriggerEvent
 from zuul.zk import ZooKeeperClient
 from zuul.zk.nodepool import ZooKeeperNodepool
@@ -287,11 +290,12 @@ class Scheduler(threading.Thread):
 
     log = logging.getLogger("zuul.Scheduler")
     _stats_interval = 30
+    _merger_client_class = MergeClient
 
     # Number of seconds past node expiration a hold request will remain
     EXPIRED_HOLD_REQUEST_TTL = 24 * 60 * 60
 
-    def __init__(self, config, connections, testonly=False):
+    def __init__(self, config, connections, app, testonly=False):
         threading.Thread.__init__(self)
         self.daemon = True
         self.hostname = socket.getfqdn()
@@ -307,9 +311,8 @@ class Scheduler(threading.Thread):
         }
         self._hibernate = False
         self._stopped = False
-        self._zuul_app = None
-        self.executor = None
-        self.merger = None
+
+        self._zuul_app = app
         self.connections = connections
         self.statsd = get_statsd(config)
         self.rpc = rpclistener.RPCListener(config, self)
@@ -367,6 +370,11 @@ class Scheduler(threading.Thread):
         self.ansible_manager = AnsibleManager(
             default_version=default_ansible_version)
 
+        if not testonly:
+            self.executor = ExecutorClient(self.config, self)
+            self.merger = self._merger_client_class(self.config, self)
+            self.nodepool = nodepool.Nodepool(self)
+
     def start(self):
         super(Scheduler, self).start()
         self._command_running = True
@@ -409,22 +417,6 @@ class Scheduler(threading.Thread):
     def stopConnections(self):
         self.connections.stop()
 
-    def setZuulApp(self, app):
-        self._zuul_app = app
-
-    def setExecutor(self, executor):
-        self.executor = executor
-
-    def setMerger(self, merger):
-        self.merger = merger
-
-    def setNodepool(self, nodepool):
-        self.nodepool = nodepool
-
-    def setZooKeeper(self, zk_client):
-        self.zk_client = zk_client
-        self.zk_nodepool = ZooKeeperNodepool(zk_client)
-
     def runStats(self):
         while not self.stats_stop.wait(self._stats_interval):
             try: