diff --git a/tests/functional/tests/eviction/test_eviction.py b/tests/functional/tests/eviction/test_eviction.py
index a55ce14..7a004c9 100644
--- a/tests/functional/tests/eviction/test_eviction.py
+++ b/tests/functional/tests/eviction/test_eviction.py
@@ -4,6 +4,7 @@
 #
 
 import logging
+from math import ceil, isclose
 from ctypes import c_int
 
 import pytest
@@ -12,7 +13,7 @@ from pyocf.types.cache import Cache, CacheMode
 from pyocf.types.core import Core
 from pyocf.types.data import Data
 from pyocf.types.io import IoDir
-from pyocf.types.shared import OcfCompletion, CacheLineSize, SeqCutOffPolicy
+from pyocf.types.shared import OcfCompletion, CacheLineSize, SeqCutOffPolicy, CacheLines
 from pyocf.types.volume import Volume
 from pyocf.utils import Size
 
@@ -74,10 +75,89 @@ def test_write_size_greater_than_cache(pyocf_ctx, mode: CacheMode, cls: CacheLin
         io_size_bigger_than_cache.blocks_4k
 
 
-def send_io(exported_obj: Core, data: Data, addr: int = 0):
+@pytest.mark.parametrize("cls", CacheLineSize)
+def test_evict_overflown_pinned(pyocf_ctx, cls: CacheLineSize):
+    """ Verify if overflown pinned ioclass is evicted """
+    cache_device = Volume(Size.from_MiB(35))
+    core_device = Volume(Size.from_MiB(100))
+    cache = Cache.start_on_device(
+        cache_device, cache_mode=CacheMode.WT, cache_line_size=cls
+    )
+    core = Core.using_device(core_device)
+    cache.add_core(core)
+
+    test_ioclass_id = 1
+    pinned_ioclass_id = 2
+    pinned_ioclass_max_occupancy = 10
+
+    cache.configure_partition(
+        part_id=test_ioclass_id,
+        name="default_ioclass",
+        min_size=0,
+        max_size=100,
+        priority=1,
+    )
+    cache.configure_partition(
+        part_id=pinned_ioclass_id,
+        name="pinned_ioclass",
+        min_size=0,
+        max_size=pinned_ioclass_max_occupancy,
+        priority=-1,
+    )
+
+    cache.set_seq_cut_off_policy(SeqCutOffPolicy.NEVER)
+
+    cache_size = cache.get_stats()["conf"]["size"]
+
+    data = Data(4096)
+
+    # Populate cache with data
+    for i in range(cache_size.blocks_4k):
+        send_io(core, data, i * 4096, test_ioclass_id)
+
+    part_current_size = CacheLines(
+        cache.get_partition_info(part_id=test_ioclass_id)["_curr_size"], cls
+    )
+    assert isclose(
+        part_current_size.blocks_4k, cache_size.blocks_4k, abs_tol=Size(cls).blocks_4k
+    ), "Failed to populate the default partition"
+
+    # Repart - force overflow of second partition occupancy limit
+    pinned_double_size = ceil(
+        (cache_size.blocks_4k * pinned_ioclass_max_occupancy * 2) / 100
+    )
+    for i in range(pinned_double_size):
+        send_io(core, data, i * 4096, pinned_ioclass_id)
+
+    part_current_size = CacheLines(
+        cache.get_partition_info(part_id=pinned_ioclass_id)["_curr_size"], cls
+    )
+    assert isclose(
+        part_current_size.blocks_4k, pinned_double_size, abs_tol=Size(cls).blocks_4k
+    ), "Occupancy of pinned ioclass doesn't match expected value"
+
+    # Trigger IO to the default ioclass - force eviction from overlown ioclass
+    for i in range(cache_size.blocks_4k):
+        send_io(core, data, (cache_size.blocks_4k + i) * 4096, test_ioclass_id)
+
+    part_current_size = CacheLines(
+        cache.get_partition_info(part_id=pinned_ioclass_id)["_curr_size"], cls
+    )
+    assert isclose(
+        part_current_size.blocks_4k,
+        ceil(cache_size.blocks_4k * 0.1),
+        abs_tol=Size(cls).blocks_4k,
+    ), "Overflown part has not been evicted"
+
+
+def send_io(exported_obj: Core, data: Data, addr: int = 0, target_ioclass: int = 0):
     io = exported_obj.new_io(
         exported_obj.cache.get_default_queue(),
-        addr, data.size, IoDir.WRITE, 0, 0
+        addr,
+        data.size,
+        IoDir.WRITE,
+        target_ioclass,
+        0,
     )
 
     io.set_data(data)