Port dummy driver manage/unmanage changes to stable

Branchless manila-tempest-plugin had changes for
the manage share server feature that required changes in
the dummy driver for its manage and unmanage routines.

Here we test porting the dummy driver changes for the
manage and unmanage share and snapshot methods, omitting
the manage and unmanage methods for share servers since
these are not supported in the stable branches.

Note that backporting such changes to a stable branch
for a regular driver would likely be unacceptable given
stable policy but the dummy driver is test-only code that
never runs outside of tests.

Change-Id: Ib9e5dd3ad6b745ea1dfe442d9357a70ca4c148ec
(cherry picked from commit 6b25b0a4075550163554895b5a1e275675ef9f21)

manila/tests/share/drivers/dummy.py

@@ -303,21 +303,62 @@ class DummyDriver(driver.ShareDriver):
     @slow_me_down
     def manage_existing(self, share, driver_options):
         """Brings an existing share under Manila management."""
-        return {"size": 1, "export_locations": self._create_share(share)}
+        new_export = share['export_location']
+        old_share_id = self._get_share_id_from_export(new_export)
+        old_export = self.private_storage.get(
+            old_share_id, key='export_location')
+        if old_export.split(":/")[-1] == new_export.split(":/")[-1]:
+            result = {"size": 1, "export_locations": self._create_share(share)}
+            self.private_storage.delete(old_share_id)
+            return result
+        else:
+            msg = ("Invalid export specified, existing share %s"
+                   " could not be found" % old_share_id)
+            raise exception.ShareBackendException(msg=msg)
+
+    def _get_share_id_from_export(self, export_location):
+        values = export_location.split('share_')
+        if len(values) > 1:
+            return values[1][37:].replace("_", "-")
+        else:
+            return export_location
 
     @slow_me_down
     def unmanage(self, share):
         """Removes the specified share from Manila management."""
+        self.private_storage.update(
+            share['id'], {'export_location': share['export_location']})
 
     @slow_me_down
     def manage_existing_snapshot(self, snapshot, driver_options):
         """Brings an existing snapshot under Manila management."""
+        old_snap_id = self._get_snap_id_from_provider_location(
+            snapshot['provider_location'])
+        old_provider_location = self.private_storage.get(
+            old_snap_id, key='provider_location')
+        if old_provider_location == snapshot['provider_location']:
             self._create_snapshot(snapshot)
-        return {"size": 1, "provider_location": snapshot["provider_location"]}
+            self.private_storage.delete(old_snap_id)
+            return {"size": 1,
+                    "provider_location": snapshot["provider_location"]}
+        else:
+            msg = ("Invalid provider location specified, existing snapshot %s"
+                   " could not be found" % old_snap_id)
+            raise exception.ShareBackendException(msg=msg)
+
+    def _get_snap_id_from_provider_location(self, provider_location):
+        values = provider_location.split('snapshot_')
+        if len(values) > 1:
+            return values[1][37:].replace("_", "-")
+        else:
+            return provider_location
 
     @slow_me_down
     def unmanage_snapshot(self, snapshot):
         """Removes the specified snapshot from Manila management."""
+        self.private_storage.update(
+            snapshot['id'],
+            {'provider_location': snapshot['provider_location']})
 
     @slow_me_down
     def revert_to_snapshot(self, context, snapshot, share_access_rules,