Delete stale fixtures with bin/storage destroy

Summary:
When a PhabricatorTestCase dies after creating storage fixtures, it leaves
those storage fixtures around.  This doesn't happen often, but when it does
happen it's a pain to cleanup.  The --unittest-fixtures option helps automate
that cleanup.

Test Plan:
Ran it with --dryrun, then for real.  Became overwhelmed with a Zen like peace
after regarding the tidiness and beauty of SHOW DATABASES.

Reviewers: epriestley

Reviewed By: epriestley

CC: aran, Korvin

Differential Revision: https://secure.phabricator.com/D3858

src/infrastructure/storage/management/workflow/PhabricatorStorageManagementDestroyWorkflow.php

@@ -23,7 +23,14 @@ final class PhabricatorStorageManagementDestroyWorkflow
     $this
       ->setName('destroy')
       ->setExamples('**destroy** [__options__]')
-      ->setSynopsis('Permanently destroy all storage and data.');
+      ->setSynopsis('Permanently destroy all storage and data.')
+      ->setArguments(
+        array(
+          array(
+            'name'  => 'unittest-fixtures',
+            'help'  => "Restrict **destroy** operations to databases created ".
+                       "by PhabricatorTestCase test fixtures.",
+          )));
   }
 
   public function execute(PhutilArgumentParser $args) {
@@ -50,8 +57,20 @@ final class PhabricatorStorageManagementDestroyWorkflow
     $api = $this->getAPI();
     $patches = $this->getPatches();
 
-    $databases = $api->getDatabaseList($patches);
-    $databases[] = $api->getDatabaseName('meta_data');
+    if ($args->getArg('unittest-fixtures')) {
+      $conn = $api->getConn(null, false);
+      $databases = queryfx_all(
+        $conn,
+        'SELECT DISTINCT(TABLE_SCHEMA) AS db '.
+        'FROM INFORMATION_SCHEMA.TABLES '.
+        'WHERE TABLE_SCHEMA LIKE %>',
+        PhabricatorTestCase::NAMESPACE_PREFIX);
+      $databases = ipull($databases, 'db');
+    } else {
+      $databases = $api->getDatabaseList($patches);
+      $databases[] = $api->getDatabaseName('meta_data');
+    }
+
     foreach ($databases as $database) {
       if ($is_dry) {
         echo "DRYRUN: Would drop database '{$database}'.\n";

src/infrastructure/testing/PhabricatorTestCase.php

@@ -18,6 +18,7 @@
 
 abstract class PhabricatorTestCase extends ArcanistPhutilTestCase {
 
+  const NAMESPACE_PREFIX = 'phabricator_unittest_';
 
   /**
    * If true, put Lisk in process-isolated mode for the duration of the tests so
@@ -132,7 +133,7 @@ abstract class PhabricatorTestCase extends ArcanistPhutilTestCase {
 
   protected function newStorageFixture() {
     $bytes = Filesystem::readRandomCharacters(24);
-    $name = 'phabricator_unittest_'.$bytes;
+    $name = self::NAMESPACE_PREFIX.$bytes;
 
     return new PhabricatorStorageFixtureScopeGuard($name);
   }