pytest 7 assert断言

def add(a,b):
    return a+b

def test_assert():
    assert 6 == add(3,4)

结果：可以看出，判断的结果是6，和方法返回的结果不一致，所以导致失败。从黄色部分的报错信息可以看出，结果不一致。

test_assert.py F
test_assert.py:11 (test_assert)
7 != 6

Expected :6
Actual :7
<Click to see difference>

def test_assert():
> assert 6 == add(3,4)
E assert 6 == 7
E + where 7 = add(3, 4)

test_assert.py:13: AssertionError
[100%]

=================================== FAILURES ===================================
_________________________________ test_assert __________________________________

def test_assert():
> assert 6 == add(3,4)
E assert 6 == 7
E + where 7 = add(3, 4)

test_assert.py:13: AssertionError

def add(a,b):
    return a+b

def test_assert():
    assert 6 == add(3,4),"方法返回的值不等于6，而是等于{0}".format(add(3,4))

结果：可以看出黄色部分，这样会写清楚失败的原因，当有多个判断时，可以容易定位问题。

test_assert.py F
test_assert.py:12 (test_assert)
def test_assert():

> assert 6 == add(3,4),"方法返回的值不等于6，而是等于{0}".format(add(3,4))
E AssertionError: 方法返回的值不等于6，而是等于7
E assert 6 == 7
E + where 7 = add(3, 4)

test_assert.py:15: AssertionError
[100%]

=================================== FAILURES ===================================
_________________________________ test_assert __________________________________

def test_assert():

> assert 6 == add(3,4),"方法返回的值不等于6，而是等于{0}".format(add(3,4))
E AssertionError: 方法返回的值不等于6，而是等于7
E assert 6 == 7
E + where 7 = add(3, 4)

test_assert.py:15: AssertionError

import pytest

def test_zero_division():
    with pytest.raises(ZeroDivisionError):
        1/0

结果：可以看出并没有报错，正常情况下，不加异常是会报错的。

============================= test session starts ==============================
platform darwin -- Python 2.7.10, pytest-3.6.3, py-1.5.2, pluggy-0.6.0
rootdir: /Users/newcomer/PycharmProjects/error/wuya/pytestDemo, inifile:
plugins: metadata-1.7.0, html-1.19.0, D3-2.0.13, cov-2.5.1, catchlog-1.2.2, allure-adaptor-1.7.10, georaven-17.1.0.170collected 1 item

test_assert.py . [100%]

-- Docs: http://doc.pytest.org/en/latest/warnings.html
===================== 1 passed, 1 warnings in 0.01 seconds =====================

import pytest

def test_zero_division():
    with pytest.raises(ZeroDivisionError,message="Exceptions ZeroDivisionError") as exinfo:
        1/0

    assert exinfo.type == ZeroDivisionError
    assert str(exinfo.value) == "integer division or modulo by zero","{0}".format(exinfo.value)

结果：可以看出来，通过了一个测试用例，但是需要注意，需要把value的值转换成str类型的才可以比较，而且值是要加引号的。断言type的时候，不需要给异常类型添加引号。

raises里面的message关键字参数消息指定自定义失败消息。

============================= test session starts ==============================
platform darwin -- Python 2.7.10, pytest-3.6.3, py-1.5.2, pluggy-0.6.0
rootdir: /Users/newcomer/PycharmProjects/error/wuya/pytestDemo, inifile:
plugins: metadata-1.7.0, html-1.19.0, D3-2.0.13, cov-2.5.1, catchlog-1.2.2, allure-adaptor-1.7.10, georaven-17.1.0.170collected 1 item

test_assert.py .exinfo.type: <type ‘exceptions.ZeroDivisionError‘>
exinfo.value: integer division or modulo by zero
[100%]

===================== 1 passed, 1 warnings in 0.01 seconds =====================

import pytest

def test_exception():
    with pytest.raises(ZeroDivisionError,message="Exception ZeroDivisionError") as exinfo:
       pass

结果：可以看出来，结果中的异常是message自己定义的信息

=================================== FAILURES ===================================
________________________________ test_exception ________________________________

def test_exception():
with pytest.raises(ZeroDivisionError,message="Exception ZeroDivisionError") as exinfo:
> pass
E Failed: Exception ZeroDivisionError

test_assert.py:28: Failed

================ 1 failed, 1 warnings in 0.08 seconds ================

def is_true(num):
    if num>0:
        return True
    else:
        return False

def test_01():
    """判断是不是为真"""
    a = 5
    b = -1
    assert is_true(a)
    assert not is_true(b)

def test_02():
    """判断b包含a"""
    a = "hello"
    b = "hello world"
    assert a in b

def test_03():
    """判断是否相等"""
    a = "hello"
    b = "hello"
    c = "hello world"
    assert a == b
    assert a != c

结果：由此可以看出来，三个用例都执行成功。

============================= test session starts ==============================
platform darwin -- Python 2.7.10, pytest-3.6.3, py-1.5.2, pluggy-0.6.0
rootdir: /Users/newcomer/PycharmProjects/error/wuya/pytestDemo, inifile:
plugins: metadata-1.7.0, html-1.19.0, D3-2.0.13, cov-2.5.1, catchlog-1.2.2, allure-adaptor-1.7.10, georaven-17.1.0.170collected 3 items

test_assert.py ... [100%]

=============================== warnings summary ===============================
<undetermined location>
pytest-catchlog plugin has been merged into the core, please remove it from your requirements.

-- Docs: http://doc.pytest.org/en/latest/warnings.html
===================== 3 passed, 1 warnings in 0.02 seconds =====================