Test custom sequence's ExceptionGroup repr

Author: dr-carlos

Lib/test/test_exception_group.py

@@ -1,4 +1,4 @@
-import collections.abc
+import collections
 import types
 import unittest
 from test.support import skip_emscripten_stack_overflow, skip_wasi_stack_overflow, exceeds_recursion_limit
@@ -212,9 +212,19 @@ class MyEG(ExceptionGroup):
         excs = (ValueError(1), KeyboardInterrupt(2))
         eg = BaseExceptionGroup('test', excs)
 
-        # Ensure that other, immutable, sequences still work fine.
+        # Ensure that immutable sequences still work fine.
         self.assertEqual(repr(eg), "BaseExceptionGroup('test', (ValueError(1), KeyboardInterrupt(2)))")
 
+        # Test non-standard custom sequences.
+        excs = collections.deque([ValueError(1), TypeError(2)])
+        eg = ExceptionGroup('test', excs)
+
+        self.assertEqual(repr(eg), "ExceptionGroup('test', (ValueError(1), TypeError(2)))")
+        excs.clear()
+
+        # Ensure that clearing the exceptions sequence doesn't change the repr.
+        self.assertEqual(repr(eg), "ExceptionGroup('test', (ValueError(1), TypeError(2)))")
+
 
 def create_simple_eg():
     excs = []