test_nose2_such.py

import time
from nose2.tools import such


def slow_blocking_init():
    time.sleep(1)
    print("a second elapsed")
    time.sleep(1)
    print("a second elapsed")
    return True


with such.A('system with a fast initial setup layer') as it:

    @it.has_setup
    def setup():
        it.obj = False

    @it.should('not have obj initialized')
    def test():
        assert not it.obj


    with it.having('a second slow setup layer'):

        @it.has_setup
        def setup():
            it.obj = slow_blocking_init()

        @it.should('have obj initialized')
        def test():
            assert it.obj

it.createTests(globals())

test_nose2_such_layers.py

import time
from nose2.tools import such


def slow_blocking_init():
    time.sleep(1)
    print("a second elapsed")
    time.sleep(1)
    print("a second elapsed")
    return True


class Layer1(object):
    @classmethod
    def setUp(cls):
        it.obj = False


class Layer2(object):
    @classmethod
    def setUp(cls):
        it.obj = slow_blocking_init()


with such.A('system with a fast initial setup layer') as it:

    it.uses(Layer1)

    @it.should('not have obj initialized')
    def test():
        assert not it.obj


    with it.having('a second slow setup layer'):

        it.uses(Layer2)

        @it.should('have obj initialized')
        def test():
            assert it.obj

it.createTests(globals())

test_nose2_unittest_layers.py

import time
import unittest


def slow_blocking_init():
    time.sleep(1)
    print("a second elapsed")
    time.sleep(1)
    print("a second elapsed")
    return True


class Layer1(object):
    @classmethod
    def setUp(cls):
        cls.obj = False


class Layer2(Layer1):
    @classmethod
    def setUp(cls):
        cls.obj = slow_blocking_init()


class TestCaseLayer1(unittest.TestCase):
    layer = Layer1

    def test_initialized_obj(self):
        assert not self.layer.obj


class TestCaseLayer2(unittest.TestCase):
    layer = Layer2

    def test_slow_initialized_obj(self):
        assert self.layer.obj

The test_nose2_such and test_nose2_unittest_layers versions execute the setups in the expected order...

$ nose2 test_nose2_such --plugin nose2.plugins.layers --layer-reporter --verbose
A system with a fast initial setup layer
  should not have obj initialized ... ok
a second elapsed
a second elapsed
  having a second slow setup layer
    should have obj initialized ... ok

----------------------------------------------------------------------
Ran 2 tests in 2.004s

OK

$ nose2 test_nose2_unittest_layers --plugin nose2.plugins.layers --layer-reporter --verbose
Layer1
  test_initialized_obj (test_nose2_unittest_layers.TestCaseLayer1) ... ok
a second elapsed
a second elapsed
  Layer2
    test_slow_initialized_obj (test_nose2_unittest_layers.TestCaseLayer2) ... ok

----------------------------------------------------------------------
Ran 2 tests in 2.003s

OK

However, the test_nose2_such_layers version runs the Layer2 test cases before (or at the same time as?) executing the the Layer2 setup:

$ nose2 test_nose2_such_layers --plugin nose2.plugins.layers --layer-reporter --verbose
Layer1
  A system with a fast initial setup layer
    should not have obj initialized ... ok
  Layer2
    having a second slow setup layer
      should have obj initialized ... FAIL
a second elapsed
a second elapsed

======================================================================
FAIL: Layer2 A system with a fast initial setup layer having a second slow setup layer should have obj initialized
----------------------------------------------------------------------
Traceback (most recent call last):
  File "/Users/lorland/temp/nose2layers/test_nose2_such_layers.py", line 40, in test
    assert it.obj
AssertionError

----------------------------------------------------------------------
Ran 2 tests in 2.003s

FAILED (failures=1)