title: moving part of tests in a module into a separate module
body: <p>i have a test class with methods that each use output of previous tests. however one of the tests is growing way too large to keep it inside this one module for it to remain readable, so i'd like to split it into two files:</p>
  <p>test_mod_main.py</p>
  <pre><code>class TestMe():
    def test_1():
        ...
    def test_2():
        ...
    def test_4():
        ...
  </code></pre>
  <p>mod_for_test_3.py</p>
  <pre><code>def test_3_large()
       ...
  </code></pre>
  <p>and i need it to still run consequtively as if in a single test module, as if collected from single class, share same data, fixtures, cmd options, everything, and in the same order:<br />
  test_1 -&gt; test_2 -&gt; test_3_large -&gt; test_4</p>
  <p>is it possible?</p>