Introduce tests for cache attach/detach feature

Signed-off-by: Katarzyna Treder <katarzyna.treder@h-partners.com>

test/functional/tests/cli/test_cas_memory_usage.py

@@ -1,20 +1,25 @@
 #
 # Copyright(c) 2020-2021 Intel Corporation
-# Copyright(c) 2024 Huawei Technologies Co., Ltd.
+# Copyright(c) 2023-2025 Huawei Technologies Co., Ltd.
 # SPDX-License-Identifier: BSD-3-Clause
 #
 
 import pytest
 
+from api.cas import casadm
 from api.cas.cas_module import CasModule
+from api.cas.cli_messages import check_stderr_msg, attach_not_enough_memory
+from connection.utils.output import CmdException
 from core.test_run import TestRun
-from type_def.size import Unit
+from storage_devices.disk import DiskTypeSet, DiskType, DiskTypeLowerThan
+from type_def.size import Unit, Size
 from test_tools.os_tools import (drop_caches,
                                  is_kernel_module_loaded,
                                  load_kernel_module,
                                  unload_kernel_module,
                                  )
-from test_tools.memory import disable_memory_affecting_functions, get_mem_free, allocate_memory
+from test_tools.memory import disable_memory_affecting_functions, get_mem_free, allocate_memory, \
+    get_mem_available, unmount_ramfs
 
 
 @pytest.mark.os_dependent
@@ -65,3 +70,51 @@ def test_insufficient_memory_for_cas_module():
             TestRun.LOGGER.info(f"Cannot load OpenCAS module as expected.\n{output.stderr}")
         else:
             TestRun.LOGGER.error("Loading OpenCAS module successfully finished, but should fail.")
+
+
+@pytest.mark.require_disk("cache", DiskTypeSet([DiskType.nand, DiskType.optane]))
+@pytest.mark.require_disk("cache2", DiskTypeSet([DiskType.nand, DiskType.optane]))
+@pytest.mark.require_disk("core", DiskTypeLowerThan("cache"))
+def test_attach_cache_min_ram():
+    """
+    title: Test attach cache with insufficient memory.
+    description: |
+        Check for valid message when attaching cache with insufficient memory.
+    pass_criteria:
+      - CAS attach operation fail due to insufficient RAM.
+      - No system crash.
+    """
+
+    with TestRun.step("Prepare devices"):
+        cache_dev = TestRun.disks["cache"]
+        cache_dev.create_partitions([Size(2, Unit.GibiByte)])
+        cache_dev = cache_dev.partitions[0]
+        cache_dev2 = TestRun.disks["cache2"]
+        core_dev = TestRun.disks["core"]
+
+    with TestRun.step("Start cache and add core"):
+        cache = casadm.start_cache(cache_dev, force=True)
+        cache.add_core(core_dev)
+
+    with TestRun.step("Detach cache"):
+        cache.detach()
+
+    with TestRun.step("Set RAM workload"):
+        disable_memory_affecting_functions()
+        allocate_memory(get_mem_available() - Size(100, Unit.MegaByte))
+
+    with TestRun.step("Try to attach cache"):
+        try:
+            TestRun.LOGGER.info(
+                f"There is {get_mem_available().unit.MebiByte.value} available memory left"
+            )
+            cache.attach(device=cache_dev2, force=True)
+            TestRun.LOGGER.error(
+                f"Cache attached not as expected."
+                f"{get_mem_available()} is enough memory to complete operation")
+
+        except CmdException as exc:
+            check_stderr_msg(exc.output, attach_not_enough_memory)
+
+    with TestRun.step("Unlock RAM memory"):
+        unmount_ramfs()