pytest2/_pytest/assertion/__init__.py

153 lines
5.3 KiB
Python

"""
support for presenting detailed information in failing assertions.
"""
import py
import os
import sys
from _pytest.monkeypatch import monkeypatch
from _pytest.assertion import util
def pytest_addoption(parser):
group = parser.getgroup("debugconfig")
group.addoption('--assert',
action="store",
dest="assertmode",
choices=("rewrite", "reinterp", "plain",),
default="rewrite",
metavar="MODE",
help="""control assertion debugging tools. 'plain'
performs no assertion debugging. 'reinterp'
reinterprets assert statements after they failed
to provide assertion expression information.
'rewrite' (the default) rewrites assert
statements in test modules on import to
provide assert expression information. """)
class AssertionState:
"""State for the assertion plugin."""
def __init__(self, config, mode):
self.mode = mode
self.trace = config.trace.root.get("assertion")
def install_importhook(config, mode):
if mode == "rewrite":
try:
import ast # noqa
except ImportError:
mode = "reinterp"
else:
# Both Jython and CPython 2.6.0 have AST bugs that make the
# assertion rewriting hook malfunction.
if (sys.platform.startswith('java') or
sys.version_info[:3] == (2, 6, 0)):
mode = "reinterp"
config._assertstate = AssertionState(config, mode)
_load_modules(mode)
m = monkeypatch()
config._cleanup.append(m.undo)
m.setattr(py.builtin.builtins, 'AssertionError',
reinterpret.AssertionError) # noqa
hook = None
if mode == "rewrite":
hook = rewrite.AssertionRewritingHook(config) # noqa
sys.meta_path.insert(0, hook)
config._assertstate.hook = hook
config._assertstate.trace("configured with mode set to %r" % (mode,))
def undo():
hook = config._assertstate.hook
if hook is not None and hook in sys.meta_path:
sys.meta_path.remove(hook)
config.add_cleanup(undo)
return hook
def pytest_collection(session):
# this hook is only called when test modules are collected
# so for example not in the master process of pytest-xdist
# (which does not collect test modules)
assertstate = getattr(session.config, '_assertstate', None)
if assertstate:
if assertstate.hook is not None:
assertstate.hook.set_session(session)
def _running_on_ci():
"""Check if we're currently running on a CI system."""
env_vars = ['CI', 'BUILD_NUMBER']
return any(var in os.environ for var in env_vars)
def pytest_runtest_setup(item):
"""Setup the pytest_assertrepr_compare hook
The newinterpret and rewrite modules will use util._reprcompare if
it exists to use custom reporting via the
pytest_assertrepr_compare hook. This sets up this custom
comparison for the test.
"""
def callbinrepr(op, left, right):
"""Call the pytest_assertrepr_compare hook and prepare the result
This uses the first result from the hook and then ensures the
following:
* Overly verbose explanations are dropped unless -vv was used or
running on a CI.
* Embedded newlines are escaped to help util.format_explanation()
later.
* If the rewrite mode is used embedded %-characters are replaced
to protect later % formatting.
The result can be formatted by util.format_explanation() for
pretty printing.
"""
hook_result = item.ihook.pytest_assertrepr_compare(
config=item.config, op=op, left=left, right=right)
for new_expl in hook_result:
if new_expl:
if (sum(len(p) for p in new_expl[1:]) > 80*8 and
item.config.option.verbose < 2 and
not _running_on_ci()):
show_max = 10
truncated_lines = len(new_expl) - show_max
new_expl[show_max:] = [py.builtin._totext(
'Detailed information truncated (%d more lines)'
', use "-vv" to show' % truncated_lines)]
new_expl = [line.replace("\n", "\\n") for line in new_expl]
res = py.builtin._totext("\n~").join(new_expl)
if item.config.getvalue("assertmode") == "rewrite":
res = res.replace("%", "%%")
return res
util._reprcompare = callbinrepr
def pytest_runtest_teardown(item):
util._reprcompare = None
def pytest_sessionfinish(session):
assertstate = getattr(session.config, '_assertstate', None)
if assertstate:
if assertstate.hook is not None:
assertstate.hook.set_session(None)
def _load_modules(mode):
"""Lazily import assertion related code."""
global rewrite, reinterpret
from _pytest.assertion import reinterpret # noqa
if mode == "rewrite":
from _pytest.assertion import rewrite # noqa
# Expose this plugin's implementation for the pytest_assertrepr_compare hook
pytest_assertrepr_compare = util.assertrepr_compare