title: how to add dozen of test cases to a test suite automatically in python
body: <p>i have dozen of test cases in different folders. In the root directory there is a test runner. </p>
  
  <pre><code>unittest\
    package1\
      test1.py
      test2.py
    package2\
      test3.py
      test4.py
    testrunner.py
  </code></pre>
  
  <p>Currently I added the four test cases manually into a test suite</p>
  
  <pre><code>import unittest
  from package1.test1 import Test1
  from package1.test2 import Test2
  from package2.test3 import Test3
  from package2.test4 import Test4
  
  suite = unittest.TestSuite()
  suite.addTests(unittest.makeSuite(Test1))
  suite.addTests(unittest.makeSuite(Test2))
  suite.addTests(unittest.makeSuite(Test3))
  suite.addTests(unittest.makeSuite(Test4))
  
  result = unittest.TextTestRunner(verbosity=2).run(suite)
  if not result.wasSuccessful():
    sys.exit(1)
  </code></pre>
  
  <p>How to let test runner test all test cases automatically? Such as:</p>
  
  <pre><code>for testCase in findTestCases():
    suite.addTests(testCase)
  </code></pre>