from unittest import TestCase
from unittest import TestLoader
from unittest import TestSuite

def _breadth_first(tree,children=iter):
    """Traverse the nodes of a tree in breadth-first order.
    The first argument should be the tree root; children
    should be a function taking as argument a tree node and
    returning an iterator of the node's children.
    """
    yield tree
    last = tree
    for node in _breadth_first(tree,children):
        for child in children(node):
            yield child
            last = child
        if last == node:
            return

class AC1(TestCase):
  def testA(self):
    pass

class ZC2(TestCase):
  def testA(self):
    pass

  def testB(self):
    pass

class BC3(TestCase):
  def test0A(self):
    pass

  def test3B(self):
    pass

  def test1C(self):
    pass

if __name__ == "__main__":
  tests = TestLoader().loadTestsFromName('__main__')
  def test_children(node):
      if isinstance(node, TestSuite): return iter(node)
      return []
  #print tests

  l = list(_breadth_first(tests, test_children))
  #print l
  print 'Length:', len(l)