def assert_message_fixer(old_expr, new_expr, method, is_absl=False):
"""Fixer for assertTrue()/assertFalse()/etc.
related error fixes.
assertTrue(...) often produces less readable error information than
alternative methods like assertEqual etc.
Args:
old_expr: a ExprPattern string for the expr to match
new_expr: a template string for the replacement
method: the method to link to in the docs.
is_absl: Whether this is an absl method with absl docs.
Returns:
A fixer that replaces old_expr with new_expr.
"""
if is_absl:
# absl doesn't have docs per se.
url = f'https://github.com/abseil/abseil-py/search?q=%22def+{method}%22'
else:
url = f'https://docs.python.org/3/library/unittest.html#unittest.TestCase.{method}'
dotdotdot = fixer.ImmutableDefaultDict(lambda _: '...')
return fixer.SimplePythonFixer(
message=(
'%s is a more specific assertion, and may give more detailed error information than %s.'
% (string.Template(new_expr).substitute(dotdotdot),
string.Template(old_expr).substitute(dotdotdot))),
matcher=syntax_matchers.ExprPattern(old_expr),
replacement=syntactic_template.PythonExprTemplate(new_expr),
url=url,
category='pylint.g-generic-assert',
)
def assert_alias_fixer(
old_expr,
new_expr,
url='https://docs.python.org/3/library/unittest.html#deprecated-aliases'):
"""Fixer for deprecated unittest aliases.
Args:
old_expr: A string for an ExprPattern matching the target expr.
new_expr: A string for a PythonExprTemplate to replace it with.
url: The URL documenting the deprecation.
Returns:
A fixer that replaces old_expr with new_expr.
"""
dotdotdot = fixer.ImmutableDefaultDict(lambda _: '...')
return fixer.SimplePythonFixer(
message=('{old} is a deprecated alias for {new} in the unittest module.'
.format(
old=string.Template(old_expr).substitute(dotdotdot),
new=string.Template(new_expr).substitute(dotdotdot))),
matcher=syntax_matchers.ExprPattern(old_expr),
replacement=syntactic_template.PythonExprTemplate(new_expr),
url=url,
significant=False,
category='pylint.g-deprecated-assert',
)
def idiom_fixer(
old_expr,
new_expr,
category,
url='https://refex.readthedocs.io/en/latest/guide/fixers/idiom.html',
):
"""Fixer for making expressions "clearer" / less convoluted.
This also helps normalize them for other fixers to apply.
Args:
old_expr: An ExprPattern string for the expr to match.
new_expr: A string.Template string for the replacement.
category: A category for the fix.
url: An URL describing the fix.
Returns:
A fixer that replaces old_expr with new_expr.
"""
dotdotdot = fixer.ImmutableDefaultDict(lambda _: '...')
return fixer.SimplePythonFixer(
message=('This could be more Pythonic: %s -> %s.' %
((string.Template(old_expr).substitute(dotdotdot),
string.Template(new_expr).substitute(dotdotdot)))),
matcher=syntax_matchers.ExprPattern(old_expr),
replacement=syntactic_template.PythonExprTemplate(new_expr),
url=url,
significant=False,
category=category,
)
def assert_equivalent_under_mock(self, lhs, rhs, m):
"""Checks that lhs and rhs perform the same operations in a mock namespace.
The mock object has its _attributes_ used as members of the namespace. So,
for example, if you want to ensure a global FOO is set to 3 during
evaluation, you must set m.FOO = 3.
The mock is reset between calls, so things like return_value will not work.
Args:
lhs: An object that can be passed to eval()
rhs: An object that can be passed to eval()
m: A Mock object.
"""
m.reset_mock() # to be safe.
objs_map = fixer.ImmutableDefaultDict(lambda k: getattr(m, k))
lhs_result = None
lhs_e = None
try:
lhs_result = eval(lhs, {}, objs_map) # It's for the greater good: pylint: disable=eval-used
except Exception as e: # pylint: disable=broad-except
lhs_e = e
lhs_calls = m.mock_calls
# Rest the mock so we can reuse it. This keeps sub-mock ids the same,
# so that e.g. a(b) is the "same call".
# If we used two mocks, then b would be a different object each time,
# and the calls would not compare equal.
m.reset_mock()
rhs_result = None
rhs_e = None
try:
rhs_result = eval(rhs, {}, objs_map) # It's for the greater good: pylint: disable=eval-used
except Exception as e: # pylint: disable=broad-except
rhs_e = e
self.assertEqual(lhs_calls, m.mock_calls)
# Try to check that the return values are at least remotely similar.
# Either the return values are equal (e.g. 1L == 1), or the types are the
# same (eg. object() != object(), but we'd still like that case to pass.)
self.assertTrue(
lhs_result == rhs_result or type(lhs_result) == type(rhs_result), # pylint: disable=unidiomatic-typecheck
'{!r} != {!r}'.format(lhs_result, rhs_result))
self.assertEqual(type(lhs_e), type(rhs_e))
def test_len(self):
self.assertEmpty(fixer.ImmutableDefaultDict(lambda _: 'a'))
def test_replacement(self):
self.assertEqual(
string.Template('$a == $b').substitute(
fixer.ImmutableDefaultDict(lambda k: k)), 'a == b')