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Merged
merged 4 commits into from
Mar 26, 2024
Merged

gh-83845: Add tests for operator module #115883

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8717c9b
Add tests for operator module.
tirkarthi Jan 13, 2020
4155be9
Refactor not_ tests like truth test. Check iconcat with objects suppo…
tirkarthi Mar 14, 2020
a0279ee
Merge remote-tracking branch 'upstream/main' into 18537-add-test-oper…
hugovk Feb 24, 2024
0341f65
Test operator.index with int, float, Fraction, Decimal, None
hugovk Feb 24, 2024
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47 changes: 47 additions & 0 deletions Lib/test/test_operator.py
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Original file line number Diff line number Diff line change
@@ -1,6 +1,8 @@
import unittest
import pickle
import sys
from decimal import Decimal
from fractions import Fraction

from test import support
from test.support import import_helper
Expand Down Expand Up @@ -508,6 +510,44 @@ def __getitem__(self, other): return 5 # so that C is a sequence
self.assertEqual(operator.ixor (c, 5), "ixor")
self.assertEqual(operator.iconcat (c, c), "iadd")

def test_iconcat_without_getitem(self):
operator = self.module

msg = "'int' object can't be concatenated"
with self.assertRaisesRegex(TypeError, msg):
operator.iconcat(1, 0.5)

def test_index(self):
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@JelleZijlstra JelleZijlstra Mar 26, 2024

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Looking at the code, it seems like this one has some additional behavior in the C version that isn't reflected in the Python version.

  1. Returning a subclass of int raises a DeprecationWarning:
>>> class X:
...     def __index__(self): return True
... 
>>> operator.index(X())
<stdin>-3:1: DeprecationWarning: __index__ returned non-int (type bool).  The ability to return an instance of a strict subclass of int is deprecated, and may be removed in a future version of Python.
  operator.index(X())
1

But the Python version returns True.

  1. If a subclass of int overrides __index__, the C version ignores it:
>>> class X(int):
...     def __index__(self): return 42
... 
>>> index(X())
42
>>> operator.index(X())
0

Arguably these are bugs, but I am not sure it's worth complicating the Python implementation for.

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@serhiy-storchaka serhiy-storchaka Mar 27, 2024

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It is a known bug, and there is an open issue for this.

operator = self.module
class X:
def __index__(self):
return 1

self.assertEqual(operator.index(X()), 1)
self.assertEqual(operator.index(0), 0)
self.assertEqual(operator.index(1), 1)
self.assertEqual(operator.index(2), 2)
with self.assertRaises((AttributeError, TypeError)):
operator.index(1.5)
with self.assertRaises((AttributeError, TypeError)):
operator.index(Fraction(3, 7))
with self.assertRaises((AttributeError, TypeError)):
operator.index(Decimal(1))
with self.assertRaises((AttributeError, TypeError)):
operator.index(None)

def test_not_(self):
operator = self.module
class C:
def __bool__(self):
raise SyntaxError
self.assertRaises(TypeError, operator.not_)
self.assertRaises(SyntaxError, operator.not_, C())
self.assertFalse(operator.not_(5))
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@serhiy-storchaka serhiy-storchaka Mar 27, 2024

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BTW, I prefer to write this like

self.assertIs(operator.not_(5), False)

to ensure that the result is boolean.

self.assertFalse(operator.not_([0]))
self.assertTrue(operator.not_(0))
self.assertTrue(operator.not_([]))

def test_length_hint(self):
operator = self.module
class X(object):
Expand All @@ -533,6 +573,13 @@ def __length_hint__(self):
with self.assertRaises(LookupError):
operator.length_hint(X(LookupError))

class Y: pass
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@JelleZijlstra JelleZijlstra Mar 26, 2024

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Here the Python and C versions will behave differently if __length_hint__ returns an instance of a subclass of int.

Python:

>>> class X:
...     def __length_hint__(self): return True
... 
>>> operator.length_hint(X())
True

C:

>>> class X:
...     def __length_hint__(self): return True
... 
>>> operator.length_hint(X())
1

Arguably a bug but again I don't know if it's worth complicating the code for.


msg = "'str' object cannot be interpreted as an integer"
with self.assertRaisesRegex(TypeError, msg):
operator.length_hint(X(2), "abc")
self.assertEqual(operator.length_hint(Y(), 10), 10)

def test_call(self):
operator = self.module

Expand Down