pyocf: unique volume ops for each volume class

Signed-off-by: Adam Rutkowski <adam.j.rutkowski@intel.com>

tests/functional/tests/management/test_start_stop.py

@@ -21,6 +21,7 @@ from pyocf.types.cache import (
     Backfill
 )
 from pyocf.types.core import Core
+from pyocf.types.ctx import OcfCtx
 from pyocf.types.data import Data
 from pyocf.types.io import IoDir
 from pyocf.types.shared import OcfError, OcfCompletion, CacheLineSize, SeqCutOffPolicy
@@ -349,6 +350,8 @@ def test_start_cache_huge_device(pyocf_ctx_log_buffer, cls):
         def submit_io(self, io):
             io.contents._end(io, 0)
 
+    OcfCtx.get_default().register_volume_type(HugeDevice)
+
     cache_device = HugeDevice()
 
     with pytest.raises(OcfError, match="OCF_ERR_INVAL_CACHE_DEV"):