test_ok2/_pytest/assertion/util.py

242 lines
8.5 KiB
Python

"""Utilities for assertion debugging"""
import py
BuiltinAssertionError = py.builtin.builtins.AssertionError
# The _reprcompare attribute on the util module is used by the new assertion
# interpretation code and assertion rewriter to detect this plugin was
# loaded and in turn call the hooks defined here as part of the
# DebugInterpreter.
_reprcompare = None
def format_explanation(explanation):
"""This formats an explanation
Normally all embedded newlines are escaped, however there are
three exceptions: \n{, \n} and \n~. The first two are intended
cover nested explanations, see function and attribute explanations
for examples (.visit_Call(), visit_Attribute()). The last one is
for when one explanation needs to span multiple lines, e.g. when
displaying diffs.
"""
# simplify 'assert False where False = ...'
where = 0
while True:
start = where = explanation.find("False\n{False = ", where)
if where == -1:
break
level = 0
for i, c in enumerate(explanation[start:]):
if c == "{":
level += 1
elif c == "}":
level -= 1
if not level:
break
else:
raise AssertionError("unbalanced braces: %r" % (explanation,))
end = start + i
where = end
if explanation[end - 1] == '\n':
explanation = (explanation[:start] + explanation[start+15:end-1] +
explanation[end+1:])
where -= 17
raw_lines = (explanation or '').split('\n')
# escape newlines not followed by {, } and ~
lines = [raw_lines[0]]
for l in raw_lines[1:]:
if l.startswith('{') or l.startswith('}') or l.startswith('~'):
lines.append(l)
else:
lines[-1] += '\\n' + l
result = lines[:1]
stack = [0]
stackcnt = [0]
for line in lines[1:]:
if line.startswith('{'):
if stackcnt[-1]:
s = 'and '
else:
s = 'where '
stack.append(len(result))
stackcnt[-1] += 1
stackcnt.append(0)
result.append(' +' + ' '*(len(stack)-1) + s + line[1:])
elif line.startswith('}'):
assert line.startswith('}')
stack.pop()
stackcnt.pop()
result[stack[-1]] += line[1:]
else:
assert line.startswith('~')
result.append(' '*len(stack) + line[1:])
assert len(stack) == 1
return '\n'.join(result)
# Provide basestring in python3
try:
basestring = basestring
except NameError:
basestring = str
def assertrepr_compare(config, op, left, right):
"""Return specialised explanations for some operators/operands"""
width = 80 - 15 - len(op) - 2 # 15 chars indentation, 1 space around op
left_repr = py.io.saferepr(left, maxsize=int(width/2))
right_repr = py.io.saferepr(right, maxsize=width-len(left_repr))
summary = '%s %s %s' % (left_repr, op, right_repr)
issequence = lambda x: isinstance(x, (list, tuple))
istext = lambda x: isinstance(x, basestring)
isdict = lambda x: isinstance(x, dict)
isset = lambda x: isinstance(x, (set, frozenset))
verbose = config.getoption('verbose')
explanation = None
try:
if op == '==':
if istext(left) and istext(right):
explanation = _diff_text(left, right, verbose)
elif issequence(left) and issequence(right):
explanation = _compare_eq_sequence(left, right, verbose)
elif isset(left) and isset(right):
explanation = _compare_eq_set(left, right, verbose)
elif isdict(left) and isdict(right):
explanation = _compare_eq_dict(left, right, verbose)
elif op == 'not in':
if istext(left) and istext(right):
explanation = _notin_text(left, right, verbose)
except py.builtin._sysex:
raise
except:
excinfo = py.code.ExceptionInfo()
explanation = [
'(pytest_assertion plugin: representation of details failed. '
'Probably an object has a faulty __repr__.)', str(excinfo)]
if not explanation:
return None
return [summary] + explanation
def _diff_text(left, right, verbose=False):
"""Return the explanation for the diff between text
Unless --verbose is used this will skip leading and trailing
characters which are identical to keep the diff minimal.
"""
explanation = []
if not verbose:
i = 0 # just in case left or right has zero length
for i in range(min(len(left), len(right))):
if left[i] != right[i]:
break
if i > 42:
i -= 10 # Provide some context
explanation = ['Skipping %s identical leading '
'characters in diff, use -v to show' % i]
left = left[i:]
right = right[i:]
if len(left) == len(right):
for i in range(len(left)):
if left[-i] != right[-i]:
break
if i > 42:
i -= 10 # Provide some context
explanation += ['Skipping %s identical trailing '
'characters in diff, use -v to show' % i]
left = left[:-i]
right = right[:-i]
explanation += [line.strip('\n')
for line in py.std.difflib.ndiff(left.splitlines(),
right.splitlines())]
return explanation
def _compare_eq_sequence(left, right, verbose=False):
explanation = []
for i in range(min(len(left), len(right))):
if left[i] != right[i]:
explanation += ['At index %s diff: %r != %r' %
(i, left[i], right[i])]
break
if len(left) > len(right):
explanation += [
'Left contains more items, first extra item: %s' %
py.io.saferepr(left[len(right)],)]
elif len(left) < len(right):
explanation += [
'Right contains more items, first extra item: %s' %
py.io.saferepr(right[len(left)],)]
return explanation # + _diff_text(py.std.pprint.pformat(left),
# py.std.pprint.pformat(right))
def _compare_eq_set(left, right, verbose=False):
explanation = []
diff_left = left - right
diff_right = right - left
if diff_left:
explanation.append('Extra items in the left set:')
for item in diff_left:
explanation.append(py.io.saferepr(item))
if diff_right:
explanation.append('Extra items in the right set:')
for item in diff_right:
explanation.append(py.io.saferepr(item))
return explanation
def _compare_eq_dict(left, right, verbose=False):
explanation = []
common = set(left).intersection(set(right))
same = dict((k, left[k]) for k in common if left[k] == right[k])
if same and not verbose:
explanation += ['Hiding %s identical items, use -v to show' %
len(same)]
elif same:
explanation += ['Common items:']
explanation += py.std.pprint.pformat(same).splitlines()
diff = set(k for k in common if left[k] != right[k])
if diff:
explanation += ['Differing items:']
for k in diff:
explanation += [py.io.saferepr({k: left[k]}) + ' != ' +
py.io.saferepr({k: right[k]})]
extra_left = set(left) - set(right)
if extra_left:
explanation.append('Left contains more items:')
explanation.extend(py.std.pprint.pformat(
dict((k, left[k]) for k in extra_left)).splitlines())
extra_right = set(right) - set(left)
if extra_right:
explanation.append('Right contains more items:')
explanation.extend(py.std.pprint.pformat(
dict((k, right[k]) for k in extra_right)).splitlines())
return explanation
def _notin_text(term, text, verbose=False):
index = text.find(term)
head = text[:index]
tail = text[index+len(term):]
correct_text = head + tail
diff = _diff_text(correct_text, text, verbose)
newdiff = ['%s is contained here:' % py.io.saferepr(term, maxsize=42)]
for line in diff:
if line.startswith('Skipping'):
continue
if line.startswith('- '):
continue
if line.startswith('+ '):
newdiff.append(' ' + line[2:])
else:
newdiff.append(line)
return newdiff