nimble_volumes: Add unit tests

Jira: CMK-37374
Change-Id: Id6bff98e3182a66d7b5b3448688b51ea64ecfec3

Author: SoloJacobs

cmk/plugins/nimble/agent_based/nimble_volumes.py

@@ -6,7 +6,7 @@
 # mypy: disable-error-code="explicit-any"
 
 import time
-from collections.abc import Mapping
+from collections.abc import Mapping, MutableMapping
 from typing import Any
 
 from cmk.agent_based.v2 import (
@@ -32,6 +32,16 @@ def discover_nimble_volumes(section: StringTable) -> DiscoveryResult:
 
 
 def check_nimble_volumes(item: str, params: Mapping[str, Any], section: StringTable) -> CheckResult:
+    yield from _check_nimble_volumes(item, params, section, time.time(), get_value_store())
+
+
+def _check_nimble_volumes(
+    item: str,
+    params: Mapping[str, Any],
+    section: StringTable,
+    now: float,
+    value_store: MutableMapping[str, object],
+) -> CheckResult:
     for line in section:
         if line[1] == item:
             if line[4] == "0":
@@ -40,11 +50,11 @@ def check_nimble_volumes(item: str, params: Mapping[str, Any], section: StringTa
             total = int(line[2])
             free = total - int(line[3])
             yield from df_check_filesystem_list(
-                get_value_store(),
+                value_store,
                 item,
                 params,
                 [(item, total, free, 0)],
-                this_time=time.time(),
+                this_time=now,
             )
 
 

tests/unit/cmk/plugins/nimble/agent_based/test_nimble_volumes.py

@@ -0,0 +1,43 @@
+#!/usr/bin/env python3
+# Copyright (C) 2026 Checkmk GmbH - License: GNU General Public License v2
+# This file is part of Checkmk (https://checkmk.com). It is subject to the terms and
+# conditions defined in the file COPYING, which is part of this source code package.
+
+import pytest
+
+from cmk.agent_based.v2 import Metric, Result, Service, State
+from cmk.plugins.lib.df import FILESYSTEM_DEFAULT_PARAMS
+from cmk.plugins.nimble.agent_based.nimble_volumes import (
+    _check_nimble_volumes,
+    discover_nimble_volumes,
+    parse_nimble_volumes,
+)
+
+STRING_TABLE = [
+    ["1", "vol-ok", "1073741824", "536870912", "1"],
+    ["", "vol-empty-size", "", "", ""],
+]
+
+
+def test_discovery_skips_volumes_without_size_data() -> None:
+    section = parse_nimble_volumes(STRING_TABLE)
+    assert list(discover_nimble_volumes(section)) == [Service(item="vol-ok")]
+
+
+def test_check_ok_volume() -> None:
+    section = parse_nimble_volumes(STRING_TABLE)
+    results = list(
+        _check_nimble_volumes(
+            "vol-ok", FILESYSTEM_DEFAULT_PARAMS, section, 60.0, {"vol-ok.delta": (0, 0)}
+        )
+    )
+    assert Metric("fs_size", 1073741824.0, boundaries=(0.0, None)) in results
+    assert Result(state=State.OK, summary="Used: 50.00% - 512 TiB of 1.00 PiB") in results
+
+
+@pytest.mark.xfail(strict=True, reason="CMK-37374")
+def test_check_does_not_crash_on_empty_size_values() -> None:
+    section = parse_nimble_volumes(STRING_TABLE)
+    assert not list(
+        _check_nimble_volumes("vol-empty-size", FILESYSTEM_DEFAULT_PARAMS, section, 60.0, {})
+    )