使用pytest.raises捕獲預期的自定義錯誤

Question

我是pytest的新手，並試圖將一些功能測試腳本轉換成pytest很好地運行的腳本。我的模塊具有自定義錯誤類型，我試圖使用「with pytest.raises（）as excinfo」方法。這是一個科學/數值軟件包，我需要測試某些方法在調用時是否一致，因此我不能深入到低層次的東西。謝謝

Answer 1

什麼是阻止您導入特定異常並在您的withpytest.raises聲明中使用它？爲什麼這不起作用？如果你能提供更多關於你面臨什麼問題的細節，那將會更有幫助。

# your code 

class CustomError(Exception): 
    pass 


def foo(): 
    raise ValueError('everything is broken') 

def bar(): 
    raise CustomError('still broken')  

#############  
# your test 

import pytest 
# import your module, or functions from it, incl. exception class  

def test_fooErrorHandling(): 
    with pytest.raises(ValueError) as excinfo: 
     foo() 
    assert excinfo.value.message == 'everything is broken' 

def test_barSimpleErrorHandling(): 
    # don't care about the specific message 
    with pytest.raises(CustomError): 
     bar() 

def test_barSpecificErrorHandling(): 
    # check the specific error message 
    with pytest.raises(MyErr) as excinfo: 
     bar() 
    assert excinfo.value.message == 'oh no!' 

def test_barWithoutImportingExceptionClass(): 
    # if for some reason you can't import the specific exception class, 
    # catch it as generic and verify it's in the str(excinfo) 
    with pytest.raises(Exception) as excinfo: 
     bar() 
    assert 'MyErr:' in str(excinfo)