title: Odoo `--test-enable` doesn't work
body: <p>I'm following <code>Odoo 10 Development Essentials</code> Chapter 2 to develop a simple todo addon. I'm using odoo's docker as my environment.</p>
  
  <p>You can check all my source code (including dockers') at <a href="https://github.com/spacegoing/docker_odoo" rel="noreferrer">https://github.com/spacegoing/docker_odoo</a></p>
  
  <p>The problem is I set up my <code>tests/</code> directory exactly the same as the book's example. However, the test only run once. After the first execution the test was never invoked. There is even no <code>.pyc</code> file in <code>tests</code> directory.</p>
  
  <p>Here are the commands I tried</p>
  
  <p><code>odoo --db_host db --db_port 5432 -r odoo -w odoo -i todo_app --test-enable --xmlrpc-port=8070 --logfile=/var/log/odoo/odoo_inst1.log</code></p>
  
  <p><code>odoo --db_host db --db_port 5432 -r odoo -w odoo -u todo_app --test-enable --xmlrpc-port=8070 --logfile=/var/log/odoo/odoo_inst1.log</code></p>
  
  <p>Notes:</p>
  
  <ol>
  <li><code>odoo-bin</code> is <code>odoo</code> in docker</li>
  <li>I've installed <code>todo_app</code> with another <code>odoo</code> instance running on port <code>8069</code></li>
  </ol>