当用例a失败的时候，如果用例b和用例c都是依赖于第一个用例的结果，那可以直接跳过用例b和c的测试，直接给他标记失败xfail
用到的场景，登录是第一个用例，登录之后的操作b是第二个用例，登录之后操作c是第三个用例，很明显三个用例都会走到登录。
如果登录都失败了，那后面2个用例就没测试必要了，直接跳过，并且标记为失败用例，这样可以节省用例时间。

用例设计

1.pytest里面用xfail标记用例为失败的用例，可以直接跳过。实现基本思路

• 把登录写为前置操作
• 对登录的账户和密码参数化，参数用canshu = [{"user":"amdin", "psw":"111"}]表示
• 多个用例放到一个Test_xx的class里
• test_01，test_02， test_03全部调用fixture里面的login功能
• test_01测试登录用例
• test_02和test_03执行前用if判断登录的结果，登录失败就执行，pytest.xfail("登录不成功, 标记为xfail")

# content of test_05.py

# coding:utf-8
import pytest

canshu = [{"user":"amdin", "psw":"111"}]

@pytest.fixture(scope="module")
def login(request):
    user = request.param["user"]
    psw = request.param["psw"]
    print("正在操作登录，账号：%s, 密码：%s" % (user, psw))
    if psw:
        return True
    else:
        return False


@pytest.mark.parametrize("login", canshu, indirect=True)
class Test_xx():

    def test_01(self, login):
        ‘‘‘用例1登录‘‘‘
        result = login
        print("用例1：%s" % result)
        assert result == True


    def test_02(self, login):
        result = login
        print("用例3,登录结果：%s" % result)
        if not result:
            pytest.xfail("登录不成功, 标记为xfail")

        assert 1 == 1

    def test_03(self, login):
        result = login
        print("用例3,登录结果：%s" %result)
        if not result:
            pytest.xfail("登录不成功, 标记为xfail")

        assert 1 == 1


if __name__ == "__main__":
    pytest.main(["-s", "test_05.py"])

上面传的登录参数是登录成功的案例，三个用例全部通过

============================= test session starts =============================
platform win32 -- Python 3.6.0, pytest-3.6.3, py-1.5.4, pluggy-0.6.0
rootdir: D:\, inifile:
plugins: metadata-1.7.0, html-1.19.0, allure-adaptor-1.7.10
collected 3 items

..\..\..\..\..\..\YOYO\peizhi\test_05.py 正在操作登录，账号：amdin, 密码：111
用例1：True
.用例3,登录结果：True
.用例3,登录结果：True
.

========================== 3 passed in 0.02 seconds ===========================

标记为xfail

1.再看看登录失败情况的用例,修改登录的参数

# content of test_05.py
# coding:utf-8
import pytest

canshu = [{"user":"amdin", "psw":""}]

@pytest.fixture(scope="module")
def login(request):
    user = request.param["user"]
    psw = request.param["psw"]
    print("正在操作登录，账号：%s, 密码：%s" % (user, psw))
    if psw:
        return True
    else:
        return False


@pytest.mark.parametrize("login", canshu, indirect=True)
class Test_xx():

    def test_01(self, login):
        ‘‘‘用例1登录‘‘‘
        result = login
        print("用例1：%s" % result)
        assert result == True


    def test_02(self, login):
        result = login
        print("用例3,登录结果：%s" % result)
        if not result:
            pytest.xfail("登录不成功, 标记为xfail")

        assert 1 == 1

    def test_03(self, login):
        result = login
        print("用例3,登录结果：%s" %result)
        if not result:
            pytest.xfail("登录不成功, 标记为xfail")

        assert 1 == 1


if __name__ == "__main__":
    pytest.main(["-s", "test_05.py"])

运行结果

============================= test session starts =============================
platform win32 -- Python 3.6.0, pytest-3.6.3, py-1.5.4, pluggy-0.6.0
rootdir: D:\, inifile:
plugins: metadata-1.7.0, html-1.19.0, allure-adaptor-1.7.10
collected 3 items

..\..\..\..\..\..\YOYO\peizhi\test_05.py 正在操作登录，账号：amdin, 密码：
用例1：False
F
self = <YOYO.peizhi.test_05.Test_xx object at 0x00000000045ACF98>, login = False

    def test_01(self, login):
        ‘‘‘用例1登录‘‘‘
        result = login
        print("用例1：%s" % result)
>       assert result == True
E       assert False == True

D:\YOYO\peizhi\test_05.py:24: AssertionError
用例3,登录结果：False
x
Test ignored.用例3,登录结果：False
x
Test ignored.

================================== FAILURES ===================================
___________________________ Test_xx.test_01[login0] ___________________________

self = <YOYO.peizhi.test_05.Test_xx object at 0x00000000045ACF98>, login = False

    def test_01(self, login):
        ‘‘‘用例1登录‘‘‘
        result = login
        print("用例1：%s" % result)
>       assert result == True
E       assert False == True

D:\YOYO\peizhi\test_05.py:24: AssertionError
===================== 1 failed, 2 xfailed in 0.06 seconds =====================

从结果可以看出用例1失败了，用例2和3没执行，直接标记为xfail了