diff --git a/Lib/test/mapping_tests.py b/Lib/test/mapping_tests.py
index 53f29f605..20306e152 100644
--- a/Lib/test/mapping_tests.py
+++ b/Lib/test/mapping_tests.py
@@ -1,7 +1,7 @@
 # tests common to dict and UserDict
 import unittest
 import collections
-import sys
+from test import support
 
 
 class BasicTestMappingProtocol(unittest.TestCase):
@@ -70,8 +70,8 @@ class BasicTestMappingProtocol(unittest.TestCase):
         if not d: self.fail("Full mapping must compare to True")
         # keys(), items(), iterkeys() ...
         def check_iterandlist(iter, lst, ref):
-            self.assertTrue(hasattr(iter, '__next__'))
-            self.assertTrue(hasattr(iter, '__iter__'))
+            self.assertHasAttr(iter, '__next__')
+            self.assertHasAttr(iter, '__iter__')
             x = list(iter)
             self.assertTrue(set(x)==set(lst)==set(ref))
         check_iterandlist(iter(d.keys()), list(d.keys()),
@@ -448,7 +448,7 @@ class TestMappingProtocol(BasicTestMappingProtocol):
         class Exc(Exception): pass
 
         class baddict1(self.type2test):
-            def __init__(self):
+            def __init__(self, *args, **kwargs):
                 raise Exc()
 
         self.assertRaises(Exc, baddict1.fromkeys, [1])
@@ -595,12 +595,14 @@ class TestHashMappingProtocol(TestMappingProtocol):
         d = self._empty_mapping()
         d[1] = 1
         try:
+            count = 0
             for i in d:
                 d[i+1] = 1
+                if count >= 1:
+                    self.fail("changing dict size during iteration doesn't raise Error")
+                count += 1
         except RuntimeError:
             pass
-        else:
-            self.fail("changing dict size during iteration doesn't raise Error")
 
     def test_repr(self):
         d = self._empty_mapping()
@@ -620,9 +622,12 @@ class TestHashMappingProtocol(TestMappingProtocol):
         d = self._full_mapping({1: BadRepr()})
         self.assertRaises(Exc, repr, d)
 
+    @support.skip_wasi_stack_overflow()
+    @support.skip_emscripten_stack_overflow()
+    @support.skip_if_sanitizer("requires deep stack", ub=True)
     def test_repr_deep(self):
         d = self._empty_mapping()
-        for i in range(sys.getrecursionlimit() + 100):
+        for i in range(support.exceeds_recursion_limit()):
             d0 = d
             d = self._empty_mapping()
             d[1] = d0
diff --git a/Lib/test/test_collections.py b/Lib/test/test_collections.py
index 0ed51c9f1..26d0dcb65 100644
--- a/Lib/test/test_collections.py
+++ b/Lib/test/test_collections.py
@@ -262,7 +262,7 @@ class TestChainMap(unittest.TestCase):
         d = c.new_child(b=20, c=30)
         self.assertEqual(d.maps, [{'b': 20, 'c': 30}, {'a': 1, 'b': 2}])
 
-    @unittest.expectedFailure  # TODO: RUSTPYTHON
+    @unittest.expectedFailure  # TODO: RUSTPYTHON; AssertionError: <class 'test.test_collections.TestChainMap.test_union_operators.<locals>.Subclass'> is not <class 'collections.ChainMap'>
     def test_union_operators(self):
         cm1 = ChainMap(dict(a=1, b=2), dict(c=3, d=4))
         cm2 = ChainMap(dict(a=10, e=5), dict(b=20, d=4))
@@ -2029,7 +2029,7 @@ class TestCollectionABCs(ABCTestCase):
         self.assertEqual(len(mss), len(mss2))
         self.assertEqual(list(mss), list(mss2))
 
-    @unittest.expectedFailure  # TODO: RUSTPYTHON
+    @unittest.expectedFailure  # TODO: RUSTPYTHON; AssertionError: TypeError not raised
     def test_illegal_patma_flags(self):
         with self.assertRaises(TypeError):
             class Both(Collection):
diff --git a/Lib/test/test_deque.py b/Lib/test/test_deque.py
index cd7fc8afd..f798ab4b6 100644
--- a/Lib/test/test_deque.py
+++ b/Lib/test/test_deque.py
@@ -726,7 +726,7 @@ class TestBasic(unittest.TestCase):
             d.append(1)
             gc.collect()
 
-    @unittest.expectedFailure  # TODO: RUSTPYTHON
+    @unittest.expectedFailure  # TODO: RUSTPYTHON; AssertionError: False is not true : Cycle was not collected
     def test_container_iterator(self):
         # Bug #3680: tp_traverse was not implemented for deque iterator objects
         class C(object):
@@ -817,7 +817,7 @@ class TestSubclass(unittest.TestCase):
         d.clear()
         self.assertEqual(len(d), 0)
 
-    @unittest.expectedFailure  # TODO: RUSTPYTHON
+    @unittest.expectedFailure  # TODO: RUSTPYTHON; AttributeError: 'Deque' object has no attribute 'x'
     def test_copy_pickle(self):
         for cls in Deque, DequeWithSlots:
             for d in cls('abc'), cls('abcde', maxlen=4):
@@ -842,7 +842,7 @@ class TestSubclass(unittest.TestCase):
                     self.assertEqual(e.z, d.z)
                     self.assertNotHasAttr(e, 'y')
 
-    @unittest.expectedFailure  # TODO: RUSTPYTHON
+    @unittest.expectedFailure  # TODO: RUSTPYTHON; AttributeError: 'Deque' object has no attribute 'x'
     def test_pickle_recursive(self):
         for proto in range(pickle.HIGHEST_PROTOCOL + 1):
             for d in Deque('abc'), Deque('abc', 3):