1 引入

• pytest使用assert进行断言，如果有多个断言，第一个失败了，那么后续的断言将不会执行；
• 那么如果第一个断言失败了，还想继续保持执行后边的断言，那如何做？
• 我们可以使用pytest-assume来解决这个问题，即使用多重断言插件。

2 pytest-assume安装

pip3 install pytest-assume

C:\Users\Administrator>pip3 install pytest-assume
Looking in indexes: https://pypi.tuna.tsinghua.edu.cn/simple
Collecting pytest-assume
  Downloading https://pypi.tuna.tsinghua.edu.cn/packages/e8/5d/ecd54af3d3dc3f69e9cf527449a51bd5ca39cd47aaeab9a74e55603a9ce1/pytest_assume-2.4.3-py3-none-any.whl (6.0 kB)
Requirement already satisfied: pytest>=2.7 in d:\python37\lib\site-packages (from pytest-assume) (6.2.4)
Requirement already satisfied: six in d:\python37\lib\site-packages (from pytest-assume) (1.15.0)
Requirement already satisfied: importlib-metadata>=0.12 in d:\python37\lib\site-packages (from pytest>=2.7->pytest-assume) (2.1.1)
Requirement already satisfied: atomicwrites>=1.0 in d:\python37\lib\site-packages (from pytest>=2.7->pytest-assume) (1.4.0)
Requirement already satisfied: toml in d:\python37\lib\site-packages (from pytest>=2.7->pytest-assume) (0.10.2)
Requirement already satisfied: pluggy<1.0.0a1,>=0.12 in d:\python37\lib\site-packages (from pytest>=2.7->pytest-assume) (0.13.1)
Requirement already satisfied: py>=1.8.2 in d:\python37\lib\site-packages (from pytest>=2.7->pytest-assume) (1.10.0)
Requirement already satisfied: colorama in d:\python37\lib\site-packages (from pytest>=2.7->pytest-assume) (0.4.4)
Requirement already satisfied: iniconfig in d:\python37\lib\site-packages (from pytest>=2.7->pytest-assume) (1.1.1)
Requirement already satisfied: packaging in d:\python37\lib\site-packages (from pytest>=2.7->pytest-assume) (20.8)
Requirement already satisfied: attrs>=19.2.0 in d:\python37\lib\site-packages (from pytest>=2.7->pytest-assume) (20.3.0)
Requirement already satisfied: zipp>=0.5 in d:\python37\lib\site-packages (from importlib-metadata>=0.12->pytest>=2.7->pytest-assume) (1.2.0)
Requirement already satisfied: pyparsing>=2.0.2 in d:\python37\lib\site-packages (from packaging->pytest>=2.7->pytest-assume) (2.4.7)
Installing collected packages: pytest-assume
Successfully installed pytest-assume-2.4.3

3 assert断言

• 先看pytest自带的assert断言效果：

# -*- coding:utf-8 -*-
# 作者：虫无涯
# 日期：2023/3/16 
# 文件名称：test_assume.py
# 作用：pytest-assume插件的使用
# 联系：VX(NoamaNelson)
# 博客：https://blog.csdn.net/NoamaNelson

import pytest

def test_case():
    a = 100
    b = 200
    assert a + b < 100
    assert a - b > 0
    assert a * b == 20000
    assert a / b == 200
    assert (b - a) / a == 1


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

• 运行结果如下，可以看到第一个断言失败后，后边的断言是无法进行的：

collecting ... collected 1 item

test_assume.py::test_case FAILED                                         [100%]
test_case\test_j\test_assume.py:8 (test_case)
def test_case():
        a = 100
        b = 200
>       assert a + b < 100
E       assert (100 + 200) < 100

test_assume.py:12: AssertionError

断言失败

断言失败


================================== FAILURES ===================================
__________________________________ test_case __________________________________

    def test_case():
        a = 100
        b = 200
>       assert a + b < 100
E       assert (100 + 200) < 100

test_assume.py:12: AssertionError
=========================== short test summary info ===========================
FAILED test_assume.py::test_case - assert (100 + 200) < 100
============================== 1 failed in 0.15s ==============================

4 pytest-assume断言

• 代码如下：

# -*- coding:utf-8 -*-
# 作者：虫无涯
# 日期：2023/3/16 
# 文件名称：test_assume.py
# 作用：pytest-assume插件的使用
# 联系：VX(NoamaNelson)
# 博客：https://blog.csdn.net/NoamaNelson

import pytest


# def test_case():
#     a = 100
#     b = 200
#     assert a + b < 100
#     assert a - b > 0
#     assert a * b == 20000
#     assert a / b == 200
#     assert (b - a) / a == 1


def test_case01():
    a = 100
    b = 200
    pytest.assume(a + b < 100)
    pytest.assume(a - b > 0)
    pytest.assume(a * b == 20000)
    pytest.assume(a / b == 200)
    pytest.assume((b - a) / a == 1)
    print("执行到这了~~~~~~~~~~")


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

• 执行结果如下，可以看到前边有断言失败的，后边的断言是继续进行的：

test_assume.py::test_case01 FAILED                                       [100%]执行到这了~~~~~~~~~~

test_case\test_j\test_assume.py:21 (test_case01)
tp = <class 'pytest_assume.plugin.FailedAssumption'>, value = None, tb = None

    def reraise(tp, value, tb=None):
        try:
            if value is None:
                value = tp()
            if value.__traceback__ is not tb:
>               raise value.with_traceback(tb)
E               pytest_assume.plugin.FailedAssumption: 
E               3 Failed Assumptions:
E               
E               test_assume.py:25: AssumptionFailure
E               >>	pytest.assume(a + b < 100)
E               AssertionError: assert False
E               
E               test_assume.py:26: AssumptionFailure
E               >>	pytest.assume(a - b > 0)
E               AssertionError: assert False
E               
E               test_assume.py:28: AssumptionFailure
E               >>	pytest.assume(a / b == 200)
E               AssertionError: assert False

D:\Python37\lib\site-packages\six.py:702: FailedAssumption

断言失败

断言失败


================================== FAILURES ===================================
_________________________________ test_case01 _________________________________

tp = <class 'pytest_assume.plugin.FailedAssumption'>, value = None, tb = None

    def reraise(tp, value, tb=None):
        try:
            if value is None:
                value = tp()
            if value.__traceback__ is not tb:
>               raise value.with_traceback(tb)
E               pytest_assume.plugin.FailedAssumption: 
E               3 Failed Assumptions:
E               
E               test_assume.py:25: AssumptionFailure
E               >>	pytest.assume(a + b < 100)
E               AssertionError: assert False
E               
E               test_assume.py:26: AssumptionFailure
E               >>	pytest.assume(a - b > 0)
E               AssertionError: assert False
E               
E               test_assume.py:28: AssumptionFailure
E               >>	pytest.assume(a / b == 200)
E               AssertionError: assert False

D:\Python37\lib\site-packages\six.py:702: FailedAssumption
---------------------------- Captured stdout call -----------------------------
执行到这了~~~~~~~~~~
=========================== short test summary info ===========================
FAILED test_assume.py::test_case01 - pytest_assume.plugin.FailedAssumption: 
============================== 1 failed in 0.17s ==============================