pytest和基于产出的测试

Question

我正试图将一堆测试从鼻子迁移到pytest，而且我无法迁移验证整个过程的一个测试。

我已经简单化下来，以表示我的问题：

def is_equal(a, b): 
    assert a == b 


def inner(): 
    yield is_equal, 2, 2 
    yield is_equal, 3, 3 


def test_simple(): 
    yield is_equal, 0, 0 
    yield is_equal, 1, 1 
    for test in inner(): 
     yield test 
    yield is_equal, 4, 4 
    yield is_equal, 5, 5 


def test_complex(): 

    integers = list() 

    def update_integers(): 
     integers.extend([0, 1, 2, 3, 4, 5]) 

    yield update_integers 

    for x in integers: 
     yield is_equal, x, x 

test_simple运行鼻子和pytest之间的罚款，但test_complex只运行初始update_integers测试：

~/projects/testbox$ nosetests -v 
test_nose_tests.test_simple(0, 0) ... ok 
test_nose_tests.test_simple(1, 1) ... ok 
test_nose_tests.test_simple(2, 2) ... ok 
test_nose_tests.test_simple(3, 3) ... ok 
test_nose_tests.test_simple(4, 4) ... ok 
test_nose_tests.test_simple(5, 5) ... ok 
test_nose_tests.test_complex ... ok 
test_nose_tests.test_complex(0, 0) ... ok 
test_nose_tests.test_complex(1, 1) ... ok 
test_nose_tests.test_complex(2, 2) ... ok 
test_nose_tests.test_complex(3, 3) ... ok 
test_nose_tests.test_complex(4, 4) ... ok 
test_nose_tests.test_complex(5, 5) ... ok 

---------------------------------------------------------------------- 
Ran 13 tests in 0.004s 


~/projects/testbox$ pytest -v 
====================================================================  test session starts   ===================================================================== 
platform linux2 -- Python 2.7.12, pytest-3.0.6, py-1.4.32, pluggy-0.4.0 -- /usr/bin/python 
cachedir: .cache 
rootdir: /home/local/ANT/cladam/projects/testbox, inifile: 
collected 7 items 

tests/test_nose_tests.py::test_simple::[0] PASSED 
tests/test_nose_tests.py::test_simple::[1] PASSED 
tests/test_nose_tests.py::test_simple::[2] PASSED 
tests/test_nose_tests.py::test_simple::[3] PASSED 
tests/test_nose_tests.py::test_simple::[4] PASSED 
tests/test_nose_tests.py::test_simple::[5] PASSED 
tests/test_nose_tests.py::test_complex::[0] PASSED 

=================================================================== pytest-warning summary  =================================================================== 
WC1 /home/local/ANT/cladam/projects/testbox/tests/test_nose_tests.py yield tests are deprecated, and scheduled to be removed in pytest 4.0 
.... 
======================================================== 7 passed, 7  pytest-warnings in 0.01 seconds ========================================================= 

我假设这是因为在收集时整数列表是空的，并且它不收集6个额外的收益。

有没有什么方法可以在pytest中复制这个测试结构？通过pytest_generate_tests？

这个测试代表了一个更大的事件序列，以建立一个对象并对其进行操作，并在该过程的每个阶段进行测试。

1. 型号的东西
2. 验证一些模特属性
3. 创建和输出文件基于模型
4. DIFF与已知的输出，看看是否有变化。

在此先感谢

Answer 1

随着你的测试输出建议，基于收益率的测试已被弃用：

WC1 /home/local/ANT/cladam/projects/testbox/tests/test_nose_tests.py yield tests are deprecated, and scheduled to be removed in pytest 4.0 

我建议你尽量使用pytest.parametrize代替，你可以查看更多约在这里：http://doc.pytest.org/en/latest/parametrize.html

从你的例子我会创造像这样的测试：

def is_equal(a, b): 
    return a == b 


import pytest 

class TestComplexScenario: 
    @pytest.mark.parametrize("my_integer", [0, 1, 2]) 
    def test_complex(self, my_integer): 
     assert is_equal(my_integer, my_integer) 

在这里有输出的一个样本：

test_complex.py::TestComplexScenario::test_complex[0] PASSED 
test_complex.py::TestComplexScenario::test_complex[1] PASSED 
test_complex.py::TestComplexScenario::test_complex[2] PASSED 

在这里您可以找到有关参数多态的一些例子：http://layer0.authentise.com/pytest-and-parametrization.html

您也可以置换为您的测试输入，这里检查的例子： pytest: parameterized test with cartesian product of arguments

Answer 2

的问题是，pytest收集所有的测试运行任何人之前，因此内test_complex的update_integers功能在收集过程结束后才能调用。

通过在conftest.py中放置以下内容，您可以通过将is_generator检查从收集阶段移动到测试运行阶段来运行测试。不幸的是，挂钩不允许pytest_runtest_protocol作为生成器运行，因此pytest-3.2.1的全部内容_pytest.main.pytest_runtestloop被复制和修改。

import pytest 
from _pytest.compat import is_generator 
def pytest_pycollect_makeitem(collector, name, obj): 
    """ 
    Override the collector so that generators are saved as functions 
    to be run during the test phase rather than the collection phase. 
    """ 
    if collector.istestfunction(obj, name) and is_generator(obj): 
     return [pytest.Function(name, collector, args=(), callobj=obj)] 

def pytest_runtestloop(session): 
    """ 
    Copy of _pytest.main.pytest_runtestloop with the session iteration 
    modified to perform a subitem iteration. 
    """ 
    if (session.testsfailed and 
      not session.config.option.continue_on_collection_errors): 
     raise session.Interrupted(
      "%d errors during collection" % session.testsfailed) 

    if session.config.option.collectonly: 
     return True 

    for i, item in enumerate(session.items): 
     nextitem = session.items[i + 1] if i + 1 < len(session.items) else None 
     # The new functionality is here: treat all items as if they 
     # might have sub-items, and run through them one by one. 

     for subitem in get_subitems(item): 
      subitem.config.hook.pytest_runtest_protocol(item=subitem, nextitem=nextitem) 
      if getattr(session, "shouldfail", False): 
       raise session.Failed(session.shouldfail) 
      if session.shouldstop: 
       raise session.Interrupted(session.shouldstop) 
    return True 

def get_subitems(item): 
    """ 
    Return a sequence of subitems for the given item. If the item is 
    not a generator, then just yield the item itself as the sequence. 
    """ 
    if not isinstance(item, pytest.Function): 
     yield item 
    obj = item.obj 
    if is_generator(obj): 
     for number, yielded in enumerate(obj()): 
      index, call, args = interpret_yielded_test(yielded, number) 
      test = pytest.Function(item.name+index, item.parent, args=args, callobj=call) 
      yield test 
    else: 
     yield item 


def interpret_yielded_test(obj, number): 
    """ 
    Process an item yielded from a generator. If the item is named, 
    then set the index to "['name']", otherwise set it to "[number]". 
    Return the index, the callable and the arguments to the callable. 
    """ 
    if not isinstance(obj, (tuple, list)): 
     obj = (obj,) 
    if not callable(obj[0]): 
     index = "['%s']"%obj[0] 
     obj = obj[1:] 
    else: 
     index = "[%d]"%number 
    call, args = obj[0], obj[1:] 
    return index, call, args 

以上可能不起作用，如果自3.2.1版本以来pytest已经发生了太多变化。请根据需要复制并修改最新版本的_pytest.main.pytest_runtestloop;这应该为您的项目提供时间，使其逐渐从基于收益的测试用例或至少收集到可在收集时收集的基于收益的测试用例中迁移。