py.test:隐藏unittest模块中的stacktrace行

Question

py.test stacktraces目前看起来像这样:

Traceback (most recent call last):
  File "/home/foo_tbz_di476/src/djangotools/djangotools/tests/ReadonlyModelTestCommon.py", line 788, in test_stale_or_missing_content_types
    self.assertEqual([], errors, 'Stale/Missing ContentTypes: %s' % '\n'.join(errors))
  File "/usr/lib64/python2.7/unittest/case.py", line 511, in assertEqual
    assertion_func(first, second, msg=msg)
  File "/usr/lib64/python2.7/unittest/case.py", line 740, in assertListEqual
    self.assertSequenceEqual(list1, list2, msg, seq_type=list)
  File "/usr/lib64/python2.7/unittest/case.py", line 722, in assertSequenceEqual
    self.fail(msg)
  File "/usr/lib64/python2.7/unittest/case.py", line 408, in fail
    raise self.failureException(msg)

如果输出会跳过unittest模块中的线条,对我的人眼来说会容易得多.

例:

Traceback (most recent call last):
  File "/home/foo_tbz_di476/src/djangotools/djangotools/tests/ReadonlyModelTestCommon.py", line 788, in test_stale_or_missing_content_types
    self.assertEqual([], errors, 'Stale/Missing ContentTypes: %s' % '\n'.join(errors))

我尝试过选项,--tb=short但这不会这样做.

更新

没有unix管(类似py.test ...| grep)的溶液是优选的.

Answer 1

看起来你正在调用pytest,如:

py.test --tb=native

此表单将输出从traceback.format_exception派生的python stdlib stacktrace

使用pytest,您可以将conftest.py文件添加到项目中.在这里,您可以添加任何代码来修改pytest行为.

谨防!在以下两种方法中都使用猴子修补,人们可能会认为是邪恶的.

选项1:字符串匹配

这是最简单的方法,但如果您要搜索的字符串出现在您不想隐藏的行中,则可能会出现问题.

这种方法修补py包中的ReprEntryNative类,这是pytest的依赖.

将以下代码放入conftest.py中

import py

def test_skip_line(line):
    """decide which lines to skip, the code below will also skip the next line if this returns true"""
    return 'unittest' in line

class PatchedReprEntryNative(py._code.code.ReprEntryNative):
    def __init__(self, tblines):
        self.lines = []
        while len(tblines) > 0:
            line = tblines.pop(0)
            if test_skip_line(line):
                # skip this line and the next
                tblines.pop(0)
            else:
                self.lines.append(line)
py._code.code.ReprEntryNative = PatchedReprEntryNative

选项2:追溯框架检查

如果字符串匹配对你来说不够真实,我们可以在它被转储到字符串之前检查回溯,并且只输出不是来自一组模块的帧.

这种方法修补了traceback.extract_tb函数,它可能会杀死小狗.

将以下代码放入conftest.py中

import inspect
import linecache
import traceback
import unittest.case
import sys    

SKIPPED_MODULES = [
    unittest.case
]

def test_skip_frame(frame):
    module = inspect.getmodule(frame)
    return module in SKIPPED_MODULES

def tb_skipper(tb):
    tbnext = tb.tb_next
    while tbnext is not None:
        if test_skip_frame(tbnext.tb_frame):
            tbnext = tbnext.tb_next
        else:
            yield tbnext
    yield None

def new_extract_tb(tb, limit = None):
    if limit is None:
        if hasattr(sys, 'tracebacklimit'):
            limit = sys.tracebacklimit
    list = []
    n = 0
    new_tb_order = tb_skipper(tb) # <-- this line added
    while tb is not None and (limit is None or n < limit):
        f = tb.tb_frame
        lineno = tb.tb_lineno
        co = f.f_code
        filename = co.co_filename
        name = co.co_name
        linecache.checkcache(filename)
        line = linecache.getline(filename, lineno, f.f_globals)
        if line: line = line.strip()
        else: line = None
        list.append((filename, lineno, name, line))
        tb = next(new_tb_order) # <-- this line modified, was tb = tb.tb_next
        n = n+1
    return list
traceback.extract_tb = new_extract_tb