Fix database listing test

Travis uses `servidor_test` for its database name, and it's not
unreasonable to suggest other people could use different ones too,
so this asserts for more concrete examples including the current db.

tests/Unit/DatabaseTest.php

@@ -19,9 +19,13 @@ public function it_can_connect()
     /** @test */
     public function it_can_list_databases()
     {
+        $db = config('database.connections.mysql.database');
         $list = (new Database())->listDatabases();
 
         $this->assertIsArray($list);
-        $this->assertContains('servidor', $list);
+        $this->assertContains($db, $list);
+        $this->assertContains('information_schema', $list);
+        $this->assertContains('performance_schema', $list);
+        $this->assertContains('mysql', $list);
     }
 }