diff --git a/tests/functional/pyocf/types/core.py b/tests/functional/pyocf/types/core.py
index eddd56f..34b7efd 100644
--- a/tests/functional/pyocf/types/core.py
+++ b/tests/functional/pyocf/types/core.py
@@ -56,7 +56,7 @@ class Core:
         self,
         device: Volume,
         try_add: bool,
-        name: str = "",
+        name: str = "core",
         core_id: int = DEFAULT_ID,
         seq_cutoff_threshold: int = DEFAULT_SEQ_CUTOFF_THRESHOLD,
     ):
@@ -74,7 +74,7 @@ class Core:
                 _size=len(self.device_name) + 1,
             ),
             _core_id=self.core_id,
-            _name=name.encode("ascii") if name else None,
+            _name=cast(create_string_buffer(name.encode("ascii")), c_char_p),
             _volume_type=self.device.type_id,
             _try_add=try_add,
             _seq_cutoff_threshold=seq_cutoff_threshold,
diff --git a/tests/functional/pyocf/types/shared.py b/tests/functional/pyocf/types/shared.py
index 2467599..b317603 100644
--- a/tests/functional/pyocf/types/shared.py
+++ b/tests/functional/pyocf/types/shared.py
@@ -27,7 +27,9 @@ class OcfErrorCode(IntEnum):
     OCF_ERR_NO_FREE_RAM = auto()
     OCF_ERR_START_CACHE_FAIL = auto()
     OCF_ERR_CACHE_NOT_EXIST = auto()
+    OCF_ERR_CORE_NOT_EXIST = auto()
     OCF_ERR_CACHE_EXIST = auto()
+    OCF_ERR_CORE_EXIST = auto()
     OCF_ERR_TOO_MANY_CORES = auto()
     OCF_ERR_CORE_NOT_AVAIL = auto()
     OCF_ERR_NOT_OPEN_EXC = auto()
diff --git a/tests/functional/tests/management/test_add_remove.py b/tests/functional/tests/management/test_add_remove.py
index 56580af..9c35df7 100644
--- a/tests/functional/tests/management/test_add_remove.py
+++ b/tests/functional/tests/management/test_add_remove.py
@@ -128,7 +128,7 @@ def test_add_remove_30core(pyocf_ctx):
         stats = cache.get_stats()
         assert stats["conf"]["core_count"] == i
         core_device = Volume(S.from_MiB(10))
-        core = Core.using_device(core_device)
+        core = Core.using_device(core_device, name=f"core{i}")
         core_devices.append(core)
         cache.add_core(core)
 
@@ -158,7 +158,7 @@ def test_adding_to_random_cache(pyocf_ctx):
     # Create 50 core devices and add to random cache
     for i in range(0, core_amount):
         core_device = Volume(S.from_MiB(10))
-        core = Core.using_device(core_device)
+        core = Core.using_device(core_device, name=f"core{i}")
         core_devices[core] = randint(0, cache_amount - 1)
         cache_devices[core_devices[core]].add_core(core)
 
@@ -246,7 +246,7 @@ def test_add_remove_incrementally(pyocf_ctx, cache_mode, cls):
     # Create 5 core devices and add to cache
     for i in range(0, core_amount):
         core_device = Volume(S.from_MiB(10))
-        core = Core.using_device(core_device)
+        core = Core.using_device(core_device, name=f"core{i}")
         core_devices.append(core)
         cache.add_core(core)
 
diff --git a/tests/functional/tests/management/test_change_params.py b/tests/functional/tests/management/test_change_params.py
index d607fe6..69b25e4 100644
--- a/tests/functional/tests/management/test_change_params.py
+++ b/tests/functional/tests/management/test_change_params.py
@@ -64,9 +64,9 @@ def test_cache_change_seq_cut_off_policy(pyocf_ctx, cm, cls):
 
     # Create 2 core devices
     core_device1 = Volume(S.from_MiB(10))
-    core1 = Core.using_device(core_device1)
+    core1 = Core.using_device(core_device1, name="core1")
     core_device2 = Volume(S.from_MiB(10))
-    core2 = Core.using_device(core_device2)
+    core2 = Core.using_device(core_device2, name="core2")
 
     # Add cores
     cache.add_core(core1)
@@ -103,9 +103,9 @@ def test_core_change_seq_cut_off_policy(pyocf_ctx, cm, cls):
 
     # Create 2 core devices
     core_device1 = Volume(S.from_MiB(10))
-    core1 = Core.using_device(core_device1)
+    core1 = Core.using_device(core_device1, name="core1")
     core_device2 = Volume(S.from_MiB(10))
-    core2 = Core.using_device(core_device2)
+    core2 = Core.using_device(core_device2, name="core2")
 
     # Add cores
     cache.add_core(core1)