如何使用 pytest 在回溯中查找特定异常

Question

进行像这样的

test_raises

测试，检查是否使用 ValueError

 引发了 

pytest.raises：

import pytest


def foo():
    raise RuntimeError("Foo")


def bar():
    try:
        foo()
    except RuntimeError:
        raise ValueError("Bar")


def test_raises():
    with pytest.raises(ValueError, match="Bar"):
        bar()

如何在测试中检查

RuntimeError

是否在某个时刻也被提出？

似乎 pytest 允许您

with pytest.raises(ValueError) as exc_info:

，但不确定哪种是遍历

ExceptionInfo

以便找到

RuntimeError

的最佳方式。

Answer 1

可以通过getrepr方法获取

def test_raises():
    with pytest.raises(ValueError, match="Bar") as exc_info:
        bar()

    found = False
    for lst in exc_info.getrepr(style="short").chain:
        for tup in lst:
            if hasattr(tup, "reprentries") and "RuntimeErrors" in str(tup.reprentries):
                found = True
    assert found, "RuntimeError not found in stacktrace"