diff --git a/nova/tests/functional/api/openstack/placement/gabbits/resource-provider-bug-1779818.yaml b/nova/tests/functional/api/openstack/placement/gabbits/resource-provider-bug-1779818.yaml
new file mode 100644
index 000000000000..4fea10004137
--- /dev/null
+++ b/nova/tests/functional/api/openstack/placement/gabbits/resource-provider-bug-1779818.yaml
@@ -0,0 +1,126 @@
+# Test launchpad bug https://bugs.launchpad.net/nova/+bug/1779818
+
+fixtures:
+    - APIFixture
+
+defaults:
+    request_headers:
+        x-auth-token: admin
+        accept: application/json
+        openstack-api-version: placement latest
+
+tests:
+
+- name: post a resource provider as alt_parent
+  POST: /resource_providers
+  request_headers:
+      content-type: application/json
+  data:
+      name: alt_parent
+      uuid: $ENVIRON['ALT_PARENT_PROVIDER_UUID']
+  status: 200
+  response_json_paths:
+      $.uuid: $ENVIRON['ALT_PARENT_PROVIDER_UUID']
+      $.name: alt_parent
+      $.parent_provider_uuid: null
+      $.generation: 0
+
+- name: post another resource provider as parent
+  POST: /resource_providers
+  request_headers:
+      content-type: application/json
+  data:
+      name: parent
+      uuid: $ENVIRON['PARENT_PROVIDER_UUID']
+  status: 200
+  response_json_paths:
+      $.uuid: $ENVIRON['PARENT_PROVIDER_UUID']
+      $.name: parent
+      $.parent_provider_uuid: null
+      $.generation: 0
+
+- name: post a child resource provider of the parent
+  POST: /resource_providers
+  request_headers:
+      content-type: application/json
+  data:
+      name: child
+      uuid: $ENVIRON['RP_UUID']
+      parent_provider_uuid: $ENVIRON['PARENT_PROVIDER_UUID']
+  status: 200
+  response_json_paths:
+      $.uuid: $ENVIRON['RP_UUID']
+      $.name: child
+      $.parent_provider_uuid: $ENVIRON['PARENT_PROVIDER_UUID']
+      $.generation: 0
+
+# Let's validate that now we have two tree structures
+#  * alt_parent
+#  * parent
+#      |
+#      +-- child
+- name: list all resource providers
+  GET: /resource_providers
+  response_json_paths:
+      $.resource_providers.`len`: 3
+      $.resource_providers[?uuid="$ENVIRON['ALT_PARENT_PROVIDER_UUID']"].root_provider_uuid: $ENVIRON['ALT_PARENT_PROVIDER_UUID']
+      $.resource_providers[?uuid="$ENVIRON['ALT_PARENT_PROVIDER_UUID']"].parent_provider_uuid: null
+      $.resource_providers[?uuid="$ENVIRON['PARENT_PROVIDER_UUID']"].root_provider_uuid: $ENVIRON['PARENT_PROVIDER_UUID']
+      $.resource_providers[?uuid="$ENVIRON['PARENT_PROVIDER_UUID']"].parent_provider_uuid: null
+      $.resource_providers[?uuid="$ENVIRON['RP_UUID']"].root_provider_uuid: $ENVIRON['PARENT_PROVIDER_UUID']
+      $.resource_providers[?uuid="$ENVIRON['RP_UUID']"].parent_provider_uuid: $ENVIRON['PARENT_PROVIDER_UUID']
+
+# Let's re-parent the parent to the alternative parent
+# so that we have only one tree.
+#  * alt_parent
+#        |
+#        +-- parent
+#              |
+#              +-- child
+- name: update a parent of the parent
+  PUT: /resource_providers/$ENVIRON['PARENT_PROVIDER_UUID']
+  request_headers:
+      content-type: application/json
+  data:
+      name: parent
+      parent_provider_uuid: $ENVIRON['ALT_PARENT_PROVIDER_UUID']
+  status: 200
+
+# Let's validate that we have only one root provider now
+- name: list all resource providers updated
+  GET: /resource_providers
+  response_json_paths:
+      $.resource_providers.`len`: 3
+      $.resource_providers[?uuid="$ENVIRON['ALT_PARENT_PROVIDER_UUID']"].root_provider_uuid: $ENVIRON['ALT_PARENT_PROVIDER_UUID']
+      $.resource_providers[?uuid="$ENVIRON['ALT_PARENT_PROVIDER_UUID']"].parent_provider_uuid: null
+      $.resource_providers[?uuid="$ENVIRON['PARENT_PROVIDER_UUID']"].root_provider_uuid: $ENVIRON['ALT_PARENT_PROVIDER_UUID']
+      $.resource_providers[?uuid="$ENVIRON['PARENT_PROVIDER_UUID']"].parent_provider_uuid: $ENVIRON['ALT_PARENT_PROVIDER_UUID']
+      # Bug#1779818: The child's root should be updated to the alt_parent,
+      #              but we actually still get the native parent for root.
+      # $.resource_providers[?uuid="$ENVIRON['RP_UUID']"].root_provider_uuid: $ENVIRON['ALT_PARENT_PROVIDER_UUID']
+      $.resource_providers[?uuid="$ENVIRON['RP_UUID']"].root_provider_uuid: $ENVIRON['PARENT_PROVIDER_UUID']
+      $.resource_providers[?uuid="$ENVIRON['RP_UUID']"].parent_provider_uuid: $ENVIRON['PARENT_PROVIDER_UUID']
+
+- name: list all resource providers in a tree with the child
+  GET: /resource_providers?in_tree=$ENVIRON['RP_UUID']
+  response_json_paths:
+      # There should be 3 providers but we actually get 2
+      $.resource_providers.`len`: 2
+      $.resource_providers[?uuid="$ENVIRON['RP_UUID']"].root_provider_uuid: $ENVIRON['PARENT_PROVIDER_UUID']
+      $.resource_providers[?uuid="$ENVIRON['PARENT_PROVIDER_UUID']"].root_provider_uuid: $ENVIRON['ALT_PARENT_PROVIDER_UUID']
+
+- name: list all resource providers in a tree with the parent
+  GET: /resource_providers?in_tree=$ENVIRON['PARENT_PROVIDER_UUID']
+  response_json_paths:
+      # There should be 3 providers but we actually get 2
+      $.resource_providers.`len`: 2
+      $.resource_providers[?uuid="$ENVIRON['ALT_PARENT_PROVIDER_UUID']"].root_provider_uuid: $ENVIRON['ALT_PARENT_PROVIDER_UUID']
+      $.resource_providers[?uuid="$ENVIRON['PARENT_PROVIDER_UUID']"].root_provider_uuid: $ENVIRON['ALT_PARENT_PROVIDER_UUID']
+
+- name: list all resource providers in a tree with the alternative parent
+  GET: /resource_providers?in_tree=$ENVIRON['ALT_PARENT_PROVIDER_UUID']
+  response_json_paths:
+      # There should be 3 providers but we actually get 2
+      $.resource_providers.`len`: 2
+      $.resource_providers[?uuid="$ENVIRON['ALT_PARENT_PROVIDER_UUID']"].root_provider_uuid: $ENVIRON['ALT_PARENT_PROVIDER_UUID']
+      $.resource_providers[?uuid="$ENVIRON['PARENT_PROVIDER_UUID']"].root_provider_uuid: $ENVIRON['ALT_PARENT_PROVIDER_UUID']