fix problem with functools.singledispatch (#104) (#105)

solves #104

dirty_equals/_base.py

@@ -13,6 +13,9 @@
 
 class DirtyEqualsMeta(ABCMeta):
  def __eq__(self, other: Any) -> bool:
+ if self is other:
+ return True
+
  # this is required as fancy things happen when creating generics which include equals checks, without it,
  # we get some recursive errors
  if self is DirtyEquals or other is Generic or other is Protocol:

tests/test_base.py

@@ -1,10 +1,11 @@
 import platform
 import pprint
+from functools import singledispatch
 
 import packaging.version
 import pytest
 
-from dirty_equals import Contains, IsApprox, IsInt, IsList, IsNegative, IsOneOf, IsPositive, IsStr
+from dirty_equals import Contains, DirtyEquals, IsApprox, IsInt, IsList, IsNegative, IsOneOf, IsPositive, IsStr
 from dirty_equals.version import VERSION
 
 
@@ -192,3 +193,23 @@ def test_is_one_of(value, dirty):
 
 def test_version():
  packaging.version.parse(VERSION)
+
+
+def test_singledispatch():
+ @singledispatch
+ def dispatch(value):
+ return 'generic'
+
+ assert dispatch(IsStr()) == 'generic'
+
+ @dispatch.register
+ def _(value: DirtyEquals):
+ return 'DirtyEquals'
+
+ assert dispatch(IsStr()) == 'DirtyEquals'
+
+ @dispatch.register
+ def _(value: IsStr):
+ return 'IsStr'
+
+ assert dispatch(IsStr()) == 'IsStr'