diff --git a/test/test_cpp11features.py b/test/test_cpp11features.py
index 2fed9a73..882c712c 100644
--- a/test/test_cpp11features.py
+++ b/test/test_cpp11features.py
@@ -103,7 +103,7 @@ class C(TestSmartPtr):
             gc.collect()
             assert TestSmartPtr.s_counter == 0
 
-    @mark.xfail
+    @mark.xfail(run=False, reason="Crashes on Valgrind")
     def test04_shared_ptr_passing(self):
         """Ability to pass shared_ptr<Derived> through shared_ptr<Base>"""
 
@@ -143,7 +143,6 @@ def test04_shared_ptr_passing(self):
         gc.collect()
         assert TestSmartPtr.s_counter == 0
 
-    @mark.xfail
     def test05_unique_ptr_passing(self):
         """Ability to pass unique_ptr<Derived> through unique_ptr<Base>"""
 
@@ -357,7 +356,6 @@ def test10_optional(self):
             c = cppyy.gbl.std.nullopt
             assert cppyy.gbl.callopt(c)
 
-    @mark.xfail
     def test11_chrono(self):
         """Use of chrono and overloaded operator+"""
 
diff --git a/test/test_crossinheritance.py b/test/test_crossinheritance.py
index 99eaf7f5..89b6dfca 100644
--- a/test/test_crossinheritance.py
+++ b/test/test_crossinheritance.py
@@ -341,7 +341,7 @@ def call(self):
         gc.collect()
         assert CB.s_count == 0 + start_count
 
-    @mark.xfail(run=IS_CLANG_REPL, reason="Crashes otherwise")
+    @mark.xfail(run=False, condition=IS_CLING, reason="Crashes on Cling")
     def test11_python_in_make_shared(self):
         """Usage of Python derived objects with std::make_shared"""
 
diff --git a/test/test_datatypes.py b/test/test_datatypes.py
index 844d1d4d..395261de 100644
--- a/test/test_datatypes.py
+++ b/test/test_datatypes.py
@@ -2011,7 +2011,6 @@ class Atom {
         assert b.name     == "aap"
         assert b.buf_type == ns.SHAPE
 
-    @mark.xfail
     def test40_more_aggregates(self):
         """More aggregate testings (used to fail/report errors)"""
 
diff --git a/test/test_pythonization.py b/test/test_pythonization.py
index dc3e5f0b..6dd819f7 100644
--- a/test/test_pythonization.py
+++ b/test/test_pythonization.py
@@ -126,7 +126,7 @@ def test03_type_pinning(self):
         assert type(result) == cppyy.gbl.pyzables.MyDerived
 
 
-    @mark.xfail
+    @mark.xfail(condition=IS_CLING, reason="Fails on Cling")
     def test04_transparency(self):
         """Transparent use of smart pointers"""
 
@@ -141,7 +141,7 @@ def test04_transparency(self):
         assert mine.__smartptr__().get().m_check == 0xcdcdcdcd
         assert mine.say_hi() == "Hi!"
 
-    @mark.xfail
+    @mark.xfail(condition=IS_CLING, reason="Fails on Cling")
     def test05_converters(self):
         """Smart pointer argument passing"""
 
@@ -167,7 +167,7 @@ def test05_converters(self):
         # cppyy.gbl.mine = mine
         pz.renew_mine()
 
-    @mark.xfail
+    @mark.xfail(condition=IS_CLING, reason="Fails on Cling")
     def test06_executors(self):
         """Smart pointer return types"""
 
diff --git a/test/test_stltypes.py b/test/test_stltypes.py
index 1f385f78..22e66628 100644
--- a/test/test_stltypes.py
+++ b/test/test_stltypes.py
@@ -531,7 +531,7 @@ def test12_vector_lifeline(self):
         for val in l:
             assert hasattr(val, '__lifeline')
 
-    @mark.xfail
+    @mark.xfail(condition=IS_MAC and IS_CLING, reason="Fails on OSX-Cling")
     def test13_vector_smartptr_iteration(self):
         """Iteration over smart pointers"""
 
@@ -565,7 +565,7 @@ def test13_vector_smartptr_iteration(self):
             i += 1
         assert i == len(result)
 
-    @mark.xfail(run=not(IS_MAC and IS_CLING), condition=(IS_MAC and IS_CLING) or IS_MAC_X86, reason="Fails on OSX-Cling and OSX-X86 with clang-repl")
+    @mark.xfail(run=not(IS_MAC and IS_CLING), condition=(IS_MAC and IS_CLING), reason="Fails on OSX-Cling")
     def test14_vector_of_vector_of_(self):
         """Nested vectors"""
 
@@ -1452,7 +1452,6 @@ def test03_stllike_preinc(self):
         assert next(it).value == 1
         assert next(it).value == 2
 
-    @mark.xfail
     def test04_stllike_confusing_name(self):
         """Having "iterator" in the container name used to fail"""
 
@@ -1599,7 +1598,7 @@ def setup_class(cls):
         import cppyy
         cls.stltypes = cppyy.load_reflection_info(cls.test_dct)
 
-    @mark.xfail
+    @mark.xfail(condition=IS_MAC, reason="Fails on OSX")
     def test01_string_through_string_view(self):
         """Usage of std::string_view as formal argument"""
 
diff --git a/test/test_streams.py b/test/test_streams.py
index 9a2dc5ac..d120c645 100644
--- a/test/test_streams.py
+++ b/test/test_streams.py
@@ -49,7 +49,6 @@ def test03_consistent_naming_if_char_traits(self):
         cppyy.gbl.stringstream_base.pass_through_base(s)
         assert s.str() == "TEST STRING"
 
-    @mark.xfail
     def test04_naming_of_ostringstream(self):
         """Naming consistency of ostringstream"""
 
@@ -58,7 +57,7 @@ def test04_naming_of_ostringstream(self):
         # Check if the object created is equal in all three cases
         cl0 = cppyy.gbl.std.ostringstream
         cl1 = cppyy.gbl.std.basic_ostringstream['char']
-        cl1 = cppyy.gbl.std.basic_ostringstream['char', cppyy.gbl.std.char_traits['char'] , cppyy.gbl.std.allocator['char']]
+        cl2 = cppyy.gbl.std.basic_ostringstream['char', cppyy.gbl.std.char_traits['char'] , cppyy.gbl.std.allocator['char']]
 
         assert cl0 == cl1
         assert cl1 == cl2