cpython/Lib/test/test_traceback.py
2012-02-26 17:49:52 +10:00

352 lines
13 KiB
Python

"""Test cases for traceback module"""
from _testcapi import traceback_print, exception_print
from io import StringIO
import sys
import unittest
import re
from test.support import run_unittest, Error, captured_output
from test.support import TESTFN, unlink
import traceback
class SyntaxTracebackCases(unittest.TestCase):
# For now, a very minimal set of tests. I want to be sure that
# formatting of SyntaxErrors works based on changes for 2.1.
def get_exception_format(self, func, exc):
try:
func()
except exc as value:
return traceback.format_exception_only(exc, value)
else:
raise ValueError("call did not raise exception")
def syntax_error_with_caret(self):
compile("def fact(x):\n\treturn x!\n", "?", "exec")
def syntax_error_with_caret_2(self):
compile("1 +\n", "?", "exec")
def syntax_error_bad_indentation(self):
compile("def spam():\n print(1)\n print(2)", "?", "exec")
def test_caret(self):
err = self.get_exception_format(self.syntax_error_with_caret,
SyntaxError)
self.assertEqual(len(err), 4)
self.assertTrue(err[1].strip() == "return x!")
self.assertIn("^", err[2]) # third line has caret
self.assertEqual(err[1].find("!"), err[2].find("^")) # in the right place
err = self.get_exception_format(self.syntax_error_with_caret_2,
SyntaxError)
self.assertIn("^", err[2]) # third line has caret
self.assertTrue(err[2].count('\n') == 1) # and no additional newline
self.assertTrue(err[1].find("+") == err[2].find("^")) # in the right place
def test_nocaret(self):
exc = SyntaxError("error", ("x.py", 23, None, "bad syntax"))
err = traceback.format_exception_only(SyntaxError, exc)
self.assertEqual(len(err), 3)
self.assertEqual(err[1].strip(), "bad syntax")
def test_bad_indentation(self):
err = self.get_exception_format(self.syntax_error_bad_indentation,
IndentationError)
self.assertEqual(len(err), 4)
self.assertEqual(err[1].strip(), "print(2)")
self.assertIn("^", err[2])
self.assertEqual(err[1].find(")"), err[2].find("^"))
def test_base_exception(self):
# Test that exceptions derived from BaseException are formatted right
e = KeyboardInterrupt()
lst = traceback.format_exception_only(e.__class__, e)
self.assertEqual(lst, ['KeyboardInterrupt\n'])
def test_format_exception_only_bad__str__(self):
class X(Exception):
def __str__(self):
1/0
err = traceback.format_exception_only(X, X())
self.assertEqual(len(err), 1)
str_value = '<unprintable %s object>' % X.__name__
if X.__module__ in ('__main__', 'builtins'):
str_name = X.__name__
else:
str_name = '.'.join([X.__module__, X.__name__])
self.assertEqual(err[0], "%s: %s\n" % (str_name, str_value))
def test_without_exception(self):
err = traceback.format_exception_only(None, None)
self.assertEqual(err, ['None\n'])
def test_encoded_file(self):
# Test that tracebacks are correctly printed for encoded source files:
# - correct line number (Issue2384)
# - respect file encoding (Issue3975)
import tempfile, sys, subprocess, os
# The spawned subprocess has its stdout redirected to a PIPE, and its
# encoding may be different from the current interpreter, on Windows
# at least.
process = subprocess.Popen([sys.executable, "-c",
"import sys; print(sys.stdout.encoding)"],
stdout=subprocess.PIPE,
stderr=subprocess.STDOUT)
stdout, stderr = process.communicate()
output_encoding = str(stdout, 'ascii').splitlines()[0]
def do_test(firstlines, message, charset, lineno):
# Raise the message in a subprocess, and catch the output
try:
output = open(TESTFN, "w", encoding=charset)
output.write("""{0}if 1:
import traceback;
raise RuntimeError('{1}')
""".format(firstlines, message))
output.close()
process = subprocess.Popen([sys.executable, TESTFN],
stdout=subprocess.PIPE, stderr=subprocess.STDOUT)
stdout, stderr = process.communicate()
stdout = stdout.decode(output_encoding).splitlines()
finally:
unlink(TESTFN)
# The source lines are encoded with the 'backslashreplace' handler
encoded_message = message.encode(output_encoding,
'backslashreplace')
# and we just decoded them with the output_encoding.
message_ascii = encoded_message.decode(output_encoding)
err_line = "raise RuntimeError('{0}')".format(message_ascii)
err_msg = "RuntimeError: {0}".format(message_ascii)
self.assertIn(("line %s" % lineno), stdout[1],
"Invalid line number: {0!r} instead of {1}".format(
stdout[1], lineno))
self.assertTrue(stdout[2].endswith(err_line),
"Invalid traceback line: {0!r} instead of {1!r}".format(
stdout[2], err_line))
self.assertTrue(stdout[3] == err_msg,
"Invalid error message: {0!r} instead of {1!r}".format(
stdout[3], err_msg))
do_test("", "foo", "ascii", 3)
for charset in ("ascii", "iso-8859-1", "utf-8", "GBK"):
if charset == "ascii":
text = "foo"
elif charset == "GBK":
text = "\u4E02\u5100"
else:
text = "h\xe9 ho"
do_test("# coding: {0}\n".format(charset),
text, charset, 4)
do_test("#!shebang\n# coding: {0}\n".format(charset),
text, charset, 5)
class TracebackFormatTests(unittest.TestCase):
def test_traceback_format(self):
try:
raise KeyError('blah')
except KeyError:
type_, value, tb = sys.exc_info()
traceback_fmt = 'Traceback (most recent call last):\n' + \
''.join(traceback.format_tb(tb))
file_ = StringIO()
traceback_print(tb, file_)
python_fmt = file_.getvalue()
else:
raise Error("unable to create test traceback string")
# Make sure that Python and the traceback module format the same thing
self.assertEqual(traceback_fmt, python_fmt)
# Make sure that the traceback is properly indented.
tb_lines = python_fmt.splitlines()
self.assertEqual(len(tb_lines), 3)
banner, location, source_line = tb_lines
self.assertTrue(banner.startswith('Traceback'))
self.assertTrue(location.startswith(' File'))
self.assertTrue(source_line.startswith(' raise'))
cause_message = (
"\nThe above exception was the direct cause "
"of the following exception:\n\n")
context_message = (
"\nDuring handling of the above exception, "
"another exception occurred:\n\n")
boundaries = re.compile(
'(%s|%s)' % (re.escape(cause_message), re.escape(context_message)))
class BaseExceptionReportingTests:
def get_exception(self, exception_or_callable):
if isinstance(exception_or_callable, Exception):
return exception_or_callable
try:
exception_or_callable()
except Exception as e:
return e
def zero_div(self):
1/0 # In zero_div
def check_zero_div(self, msg):
lines = msg.splitlines()
self.assertTrue(lines[-3].startswith(' File'))
self.assertIn('1/0 # In zero_div', lines[-2])
self.assertTrue(lines[-1].startswith('ZeroDivisionError'), lines[-1])
def test_simple(self):
try:
1/0 # Marker
except ZeroDivisionError as _:
e = _
lines = self.get_report(e).splitlines()
self.assertEqual(len(lines), 4)
self.assertTrue(lines[0].startswith('Traceback'))
self.assertTrue(lines[1].startswith(' File'))
self.assertIn('1/0 # Marker', lines[2])
self.assertTrue(lines[3].startswith('ZeroDivisionError'))
def test_cause(self):
def inner_raise():
try:
self.zero_div()
except ZeroDivisionError as e:
raise KeyError from e
def outer_raise():
inner_raise() # Marker
blocks = boundaries.split(self.get_report(outer_raise))
self.assertEqual(len(blocks), 3)
self.assertEqual(blocks[1], cause_message)
self.check_zero_div(blocks[0])
self.assertIn('inner_raise() # Marker', blocks[2])
def test_context(self):
def inner_raise():
try:
self.zero_div()
except ZeroDivisionError:
raise KeyError
def outer_raise():
inner_raise() # Marker
blocks = boundaries.split(self.get_report(outer_raise))
self.assertEqual(len(blocks), 3)
self.assertEqual(blocks[1], context_message)
self.check_zero_div(blocks[0])
self.assertIn('inner_raise() # Marker', blocks[2])
def test_context_suppression(self):
try:
try:
raise Exception
except:
raise ZeroDivisionError from None
except ZeroDivisionError as _:
e = _
lines = self.get_report(e).splitlines()
self.assertEqual(len(lines), 4)
self.assertTrue(lines[0].startswith('Traceback'))
self.assertTrue(lines[1].startswith(' File'))
self.assertIn('ZeroDivisionError from None', lines[2])
self.assertTrue(lines[3].startswith('ZeroDivisionError'))
def test_cause_and_context(self):
# When both a cause and a context are set, only the cause should be
# displayed and the context should be muted.
def inner_raise():
try:
self.zero_div()
except ZeroDivisionError as _e:
e = _e
try:
xyzzy
except NameError:
raise KeyError from e
def outer_raise():
inner_raise() # Marker
blocks = boundaries.split(self.get_report(outer_raise))
self.assertEqual(len(blocks), 3)
self.assertEqual(blocks[1], cause_message)
self.check_zero_div(blocks[0])
self.assertIn('inner_raise() # Marker', blocks[2])
def test_cause_recursive(self):
def inner_raise():
try:
try:
self.zero_div()
except ZeroDivisionError as e:
z = e
raise KeyError from e
except KeyError as e:
raise z from e
def outer_raise():
inner_raise() # Marker
blocks = boundaries.split(self.get_report(outer_raise))
self.assertEqual(len(blocks), 3)
self.assertEqual(blocks[1], cause_message)
# The first block is the KeyError raised from the ZeroDivisionError
self.assertIn('raise KeyError from e', blocks[0])
self.assertNotIn('1/0', blocks[0])
# The second block (apart from the boundary) is the ZeroDivisionError
# re-raised from the KeyError
self.assertIn('inner_raise() # Marker', blocks[2])
self.check_zero_div(blocks[2])
def test_syntax_error_offset_at_eol(self):
# See #10186.
def e():
raise SyntaxError('', ('', 0, 5, 'hello'))
msg = self.get_report(e).splitlines()
self.assertEqual(msg[-2], " ^")
def e():
exec("x = 5 | 4 |")
msg = self.get_report(e).splitlines()
self.assertEqual(msg[-2], ' ^')
class PyExcReportingTests(BaseExceptionReportingTests, unittest.TestCase):
#
# This checks reporting through the 'traceback' module, with both
# format_exception() and print_exception().
#
def get_report(self, e):
e = self.get_exception(e)
s = ''.join(
traceback.format_exception(type(e), e, e.__traceback__))
with captured_output("stderr") as sio:
traceback.print_exception(type(e), e, e.__traceback__)
self.assertEqual(sio.getvalue(), s)
return s
class CExcReportingTests(BaseExceptionReportingTests, unittest.TestCase):
#
# This checks built-in reporting by the interpreter.
#
def get_report(self, e):
e = self.get_exception(e)
with captured_output("stderr") as s:
exception_print(e)
return s.getvalue()
def test_main():
run_unittest(__name__)
if __name__ == "__main__":
test_main()