bpo-37685: Fixed comparisons of datetime.timedelta and datetime.timezone. (GH-14996)

There was a discrepancy between the Python and C implementations.

Add singletons ALWAYS_EQ, LARGEST and SMALLEST in test.support
to test mixed type comparison.

1 files changed, 36 insertions, 0 deletions

diff --git a/Lib/test/support/__init__.py b/Lib/test/support/__init__.py
index dbbbdb0..c82037e 100644
--- a/Lib/test/support/__init__.py
+++ b/Lib/test/support/__init__.py
@@ -113,6 +113,7 @@ __all__ = [
     "run_with_locale", "swap_item",
     "swap_attr", "Matcher", "set_memlimit", "SuppressCrashReport", "sortdict",
     "run_with_tz", "PGO", "missing_compiler_executable", "fd_count",
+    "ALWAYS_EQ", "LARGEST", "SMALLEST"
     ]
 
 class Error(Exception):
@@ -3103,6 +3104,41 @@ class FakePath:
             return self.path
 
 
+class _ALWAYS_EQ:
+    """
+    Object that is equal to anything.
+    """
+    def __eq__(self, other):
+        return True
+    def __ne__(self, other):
+        return False
+
+ALWAYS_EQ = _ALWAYS_EQ()
+
+@functools.total_ordering
+class _LARGEST:
+    """
+    Object that is greater than anything (except itself).
+    """
+    def __eq__(self, other):
+        return isinstance(other, _LARGEST)
+    def __lt__(self, other):
+        return False
+
+LARGEST = _LARGEST()
+
+@functools.total_ordering
+class _SMALLEST:
+    """
+    Object that is less than anything (except itself).
+    """
+    def __eq__(self, other):
+        return isinstance(other, _SMALLEST)
+    def __gt__(self, other):
+        return False
+
+SMALLEST = _SMALLEST()
+
 def maybe_get_event_loop_policy():
     """Return the global event loop policy if one is set, else return None."""
     return asyncio.events._event_loop_policy