diff --git a/nova/tests/functional/api/openstack/placement/db/test_consumer.py b/nova/tests/functional/api/openstack/placement/db/test_consumer.py
index 9fe2f2493d19..9055b650a5e2 100644
--- a/nova/tests/functional/api/openstack/placement/db/test_consumer.py
+++ b/nova/tests/functional/api/openstack/placement/db/test_consumer.py
@@ -11,6 +11,7 @@
 #    under the License.
 
 from oslo_config import cfg
+from oslo_db import exception as db_exc
 import sqlalchemy as sa
 
 from nova.api.openstack.placement import db_api
@@ -104,7 +105,7 @@ class CreateIncompleteConsumersTestCase(base.TestCase):
         self.ctx = self.context
 
     @db_api.placement_context_manager.writer
-    def _create_incomplete_allocations(self, ctx):
+    def _create_incomplete_allocations(self, ctx, num_of_consumer_allocs=1):
         # Create some allocations with consumers that don't exist in the
         # consumers table to represent old allocations that we expect to be
         # "cleaned up" with consumers table records that point to the sentinel
@@ -113,10 +114,14 @@ class CreateIncompleteConsumersTestCase(base.TestCase):
         c2_missing_uuid = uuids.c2_missing
         c3_missing_uuid = uuids.c3_missing
         for c_uuid in (c1_missing_uuid, c2_missing_uuid, c3_missing_uuid):
-            ins_stmt = ALLOC_TBL.insert().values(
-                resource_provider_id=1, resource_class_id=0,
-                consumer_id=c_uuid, used=1)
-            ctx.session.execute(ins_stmt)
+            # Create $num_of_consumer_allocs allocations per consumer with
+            # different resource classes.
+            for resource_class_id in range(num_of_consumer_allocs):
+                ins_stmt = ALLOC_TBL.insert().values(
+                    resource_provider_id=1,
+                    resource_class_id=resource_class_id,
+                    consumer_id=c_uuid, used=1)
+                ctx.session.execute(ins_stmt)
         # Verify there are no records in the projects/users table
         project_count = ctx.session.scalar(
             sa.select([sa.func.count('*')]).select_from(PROJECT_TBL))
@@ -216,6 +221,31 @@ class CreateIncompleteConsumersTestCase(base.TestCase):
         res = consumer_obj.create_incomplete_consumers(self.ctx, 10)
         self.assertEqual((0, 0), res)
 
+    def test_create_incomplete_consumers_multiple_allocs_per_consumer(self):
+        """Tests that missing consumer records are created when listing
+        allocations against a resource provider or running the online data
+        migration routine when the consumers have multiple allocations on the
+        same provider.
+        """
+        self._create_incomplete_allocations(self.ctx, num_of_consumer_allocs=2)
+        # Run the online data migration to migrate one consumer. The batch size
+        # needs to be large enough to hit more than one consumer for this test
+        # where each consumer has two allocations.
+        # FIXME(mriedem): This should not raise a UniqueConstraint error once
+        # bug 1798163 is fixed.
+        # res = consumer_obj.create_incomplete_consumers(self.ctx, 2)
+        # self.assertEqual((2, 2), res)
+        self.assertRaises(db_exc.DBDuplicateEntry,
+                          consumer_obj.create_incomplete_consumers,
+                          self.ctx, 2)
+        # Migrate the rest by listing allocations on the resource provider.
+        rp1 = rp_obj.ResourceProvider(self.ctx, id=1)
+        # FIXME(mriedem): This should not raise a UniqueConstraint error once
+        # bug 1798163 is fixed.
+        self.assertRaises(db_exc.DBDuplicateEntry,
+                          rp_obj.AllocationList.get_all_by_resource_provider,
+                          self.ctx, rp1)
+
 
 class DeleteConsumerIfNoAllocsTestCase(tb.PlacementDbBaseTestCase):
     def test_delete_consumer_if_no_allocs(self):