diff --git a/tests/base.py b/tests/base.py
index 1356533c95..a4d1b87bf2 100644
--- a/tests/base.py
+++ b/tests/base.py
@@ -130,6 +130,7 @@ import tests.fakegitlab
 FIXTURE_DIR = os.path.join(os.path.dirname(__file__), 'fixtures')
 
 KEEP_TEMPDIRS = bool(os.environ.get('KEEP_TEMPDIRS', False))
+SCHEDULER_COUNT = int(os.environ.get('ZUUL_SCHEDULER_COUNT', 1))
 
 
 def repack_repo(path):
@@ -4498,6 +4499,7 @@ class ZuulTestCase(BaseTestCase):
     git_url_with_auth: bool = False
     log_console_port: int = 19885
     validate_tenants = None
+    scheduler_count = SCHEDULER_COUNT
 
     def __getattr__(self, name):
         """Allows to access fake connections the old way, e.g., using
@@ -4675,7 +4677,8 @@ class ZuulTestCase(BaseTestCase):
         self.builds = self.executor_server.running_builds
 
         self.scheds = SchedulerTestManager(self.validate_tenants)
-        self.createScheduler()
+        for _ in range(self.scheduler_count):
+            self.createScheduler()
 
         self.merge_server = None
 
diff --git a/tests/unit/test_configloader.py b/tests/unit/test_configloader.py
index 7d5dc85422..7b0e0e3a18 100644
--- a/tests/unit/test_configloader.py
+++ b/tests/unit/test_configloader.py
@@ -981,6 +981,7 @@ class TestTenantExtraConfigsInvalidValue(TenantParserTestCase):
 
 class TestTenantDuplicate(TenantParserTestCase):
     tenant_config_file = 'config/tenant-parser/duplicate.yaml'
+    scheduler_count = 1
 
     def setUp(self):
         with testtools.ExpectedException(Exception, 'Duplicate configuration'):
diff --git a/tox.ini b/tox.ini
index 3707f21653..634d3a2ced 100644
--- a/tox.ini
+++ b/tox.ini
@@ -28,6 +28,7 @@ passenv =
   YARN_REGISTRY
   ZUUL_MYSQL_HOST
   ZUUL_POSTGRES_HOST
+  ZUUL_SCHEDULER_COUNT
   ZUUL_TEST_ROOT
   ZUUL_ZK_HOST
   ZUUL_ZK_CA