Implement DestructibleInterface on Spaces, add some basic tests

Summary: Ref T8377. Mostly just a framework for test coverage.

Test Plan: Tests pass.

Reviewers: btrahan

Reviewed By: btrahan

Subscribers: epriestley

Maniphest Tasks: T8377

Differential Revision: https://secure.phabricator.com/D13102

src/applications/spaces/storage/PhabricatorSpacesNamespace.php

@@ -4,7 +4,8 @@ final class PhabricatorSpacesNamespace
   extends PhabricatorSpacesDAO
   implements
     PhabricatorPolicyInterface,
-    PhabricatorApplicationTransactionInterface {
+    PhabricatorApplicationTransactionInterface,
+    PhabricatorDestructibleInterface {
 
   protected $namespaceName;
   protected $viewPolicy;
@@ -103,4 +104,13 @@ final class PhabricatorSpacesNamespace
     return $timeline;
   }
 
+
+/* -(  PhabricatorDestructibleInterface  )----------------------------------- */
+
+
+  public function destroyObjectPermanently(
+    PhabricatorDestructionEngine $engine) {
+    $this->delete();
+  }
+
 }