# Code Review — Driver.Cli.Common

| Field | Value |
|---|---|
| Module | `src/Drivers/Cli/ZB.MOM.WW.OtOpcUa.Driver.Cli.Common` |
| Reviewer | Claude Code |
| Review date | 2026-06-19 |
| Commit reviewed | `7286d320` |
| Status | Reviewed |
| Open findings | 0 |

## Checklist coverage

A comprehensive review completes every category, recording "No issues found" where
a category produced nothing rather than leaving it blank.

| # | Category | Result |
|---|---|---|
| 1 | Correctness & logic bugs | Driver.Cli.Common-001, Driver.Cli.Common-002, Driver.Cli.Common-007 |
| 2 | OtOpcUa conventions | No issues found |
| 3 | Concurrency & thread safety | Driver.Cli.Common-003 |
| 4 | Error handling & resilience | Driver.Cli.Common-004 |
| 5 | Security | No issues found |
| 6 | Performance & resource management | No issues found |
| 7 | Design-document adherence | No issues found |
| 8 | Code organization & conventions | No issues found |
| 9 | Testing coverage | Driver.Cli.Common-005, Driver.Cli.Common-008 |
| 10 | Documentation & comments | Driver.Cli.Common-006 |

## Re-review 2026-05-23 (commit `a9be809`)

Delta scope: commit `5a9c459` extends the `FormatStatus` shortlist with five
`Bad*` codes (`BadInternalError` 0x80020000, `BadNotWritable` 0x803B0000,
`BadOutOfRange` 0x803C0000, `BadNotSupported` 0x803D0000, `BadDeviceFailure`
0x80550000) the FOCAS / AbCip / AbLegacy native-protocol mappers emit. Tests
extended with parallel `[InlineData]` rows on the well-known Theory plus a new
`FormatStatus_names_native_driver_emitted_codes` Theory.

Cross-checked the five new hex literals against the OPC Foundation
`Opc.Ua.StatusCodes` table via DeepWiki:

| Name added | Code in shortlist | Spec value | Verdict |
|---|---|---|---|
| `BadInternalError` | `0x80020000` | `0x80020000` | Correct |
| `BadNotWritable` | `0x803B0000` | `0x803B0000` | Correct |
| `BadOutOfRange` | `0x803C0000` | `0x803C0000` | Correct |
| `BadNotSupported` | `0x803D0000` | `0x803D0000` | Correct |
| `BadDeviceFailure` | `0x80550000` | **`0x808B0000`** | **WRONG — `0x80550000` is `BadSecurityPolicyRejected`** |

The `BadDeviceFailure` mismapping is the same shape of bug as the original
Driver.Cli.Common-001 (wrong hex literal copied into the shortlist); recorded
as Driver.Cli.Common-007. The wrong constant also lives in
`FocasStatusMapper.cs`, `AbCipStatusMapper.cs`, `AbLegacyStatusMapper.cs`,
`TwinCATStatusMapper.cs`, `S7Driver.cs`, and `ModbusDriver.cs` — those are in
other modules' review scope but are noted here so future re-reviewers know
this isn't isolated. (`StatusCodeMap.cs` in Driver.Galaxy + the Wonderware
historian mappers use the correct `0x808B0000`, confirming the discrepancy.)

Testing observation: the new `FormatStatus_names_native_driver_emitted_codes`
Theory is fully redundant with the well-known Theory (the five rows were also
added there in the same commit) and uses `ShouldContain` rather than
`ShouldBe` — recorded as Driver.Cli.Common-008.

Other categories (concurrency, security, performance, design-doc adherence,
code organisation, documentation) are unchanged by this delta — no new
issues found.

## Findings

### Driver.Cli.Common-001

| Field | Value |
|---|---|
| Severity | High |
| Category | Correctness & logic bugs |
| Location | `src/Drivers/Cli/ZB.MOM.WW.OtOpcUa.Driver.Cli.Common/SnapshotFormatter.cs:106-119` |
| Status | Resolved |

**Description:** The `FormatStatus` shortlist maps four OPC UA status names to incorrect
numeric codes. The correct OPC UA spec values (verified against the OPC Foundation
UA-.NETStandard `Opc.Ua.StatusCodes` table) are:

| Name in shortlist | Code used | Correct code | What the used code actually is |
|---|---|---|---|
| `BadTimeout` | `0x80060000` | `0x800A0000` | `0x80060000` = `BadOutOfMemory` |
| `BadNoCommunication` | `0x80070000` | `0x80310000` | `0x80070000` = `BadResourceUnavailable` |
| `BadWaitingForInitialData` | `0x80080000` | `0x80320000` | `0x80080000` is not this name |
| `BadNodeIdInvalid` | `0x80350000` | `0x80330000` | `0x80350000` = `BadNodeClassInvalid` |

`Good` (`0x00000000`), `Bad` (`0x80000000`), `BadCommunicationError` (`0x80050000`),
`BadNodeIdUnknown` (`0x80340000`), `BadTypeMismatch` (`0x80740000`), and `Uncertain`
(`0x40000000`) are correct.

This is operator-facing and load-bearing: the CLI whole purpose is to label driver
status codes so a human can interpret a probe/read/write. A real device timeout
(`0x800A0000`) renders as bare `0x800A0000` with no name, while an out-of-memory
status (`0x80060000`) is mislabeled `BadTimeout`. A driver returning
`BadNodeClassInvalid` (`0x80350000`) is mislabeled `BadNodeIdInvalid`. The
`SnapshotFormatterTests` `[Theory]` cases for these codes assert against the wrong
expectations and therefore pass while the mapping is wrong (see Driver.Cli.Common-005).

**Recommendation:** Correct the four mappings to the spec values. Prefer deriving names
from the OPC Foundation `Opc.Ua.StatusCodes` constants (the stack the project already
depends on transitively) rather than hand-maintaining a hex shortlist, so the table
cannot drift from the spec again. If a hand-list is kept, add a test that cross-checks
each entry against `Opc.Ua.StatusCodes` reflection.

**Resolution:** Resolved 2026-05-22 — corrected the four mismapped `FormatStatus` codes
to their canonical `Opc.Ua.StatusCodes` values (`BadTimeout` 0x800A0000, `BadNoCommunication`
0x80310000, `BadWaitingForInitialData` 0x80320000, `BadNodeIdInvalid` 0x80330000); the CLI
project does not reference the `Opc.Ua` package so the hex literals were corrected in place
with a sync note, and `SnapshotFormatterTests` was updated with corrected expectations plus
a regression `[Theory]` asserting the pre-fix wrong names no longer apply.

### Driver.Cli.Common-002

| Field | Value |
|---|---|
| Severity | Medium |
| Category | Correctness & logic bugs |
| Location | `src/Drivers/Cli/ZB.MOM.WW.OtOpcUa.Driver.Cli.Common/SnapshotFormatter.cs:101-122` |
| Status | Resolved |

**Description:** `FormatStatus` matches the full 32-bit status word for exact equality
against the shortlist. OPC UA status codes carry sub-code/flag bits in the low 16 bits
(info type, structure-changed, semantics-changed, limit bits, overflow, etc.). A
driver-supplied status such as `0x80050001` or any `Good` value with info bits set
(e.g. an overflow bit) falls through the `switch` and renders as bare hex even though
the high bits clearly identify the severity class. The doc comment on `FormatStatus`
claims the well-known statuses are named, but only the bit-exact canonical forms are.

**Recommendation:** Either (a) narrow the doc-comment claim to bit-exact canonical
codes, or (b) match on the severity bits (`code & 0xC0000000`) to at least always emit
`Good` / `Uncertain` / `Bad` even when sub-code bits are set, and match the named codes
on the masked code (`code & 0xFFFF0000`).

**Resolution:** Resolved 2026-05-22 — `FormatStatus` now matches named codes on `code & 0xFFFF0000` and falls back to a severity-class label (`Good`/`Uncertain`/`Bad`) via `code & 0xC0000000` for unknown sub-codes; the stale "bare-hex for unknown codes" test expectation was corrected to reflect the new severity-class fallback.

### Driver.Cli.Common-003

| Field | Value |
|---|---|
| Severity | Medium |
| Category | Concurrency & thread safety |
| Location | `src/Drivers/Cli/ZB.MOM.WW.OtOpcUa.Driver.Cli.Common/DriverCommandBase.cs:51-59` |
| Status | Resolved |

**Description:** `ConfigureLogging` assigns the process-global `Serilog.Log.Logger`
without disposing the previously assigned logger and the library never calls
`Log.CloseAndFlush()`. Each call creates a fresh `Logger` via `CreateLogger()` and
overwrites `Log.Logger`; the prior instance (and its console sink) is never disposed
or flushed. The class is the shared base for every driver CLI and the `subscribe` verb
is long-running — if any command path re-invokes `ConfigureLogging` the buffered
console sink is abandoned without a flush, and on process exit the final logger is also
never flushed. Verbose debug output written just before exit can be lost.

**Recommendation:** Call `Log.CloseAndFlush()` on shutdown (e.g. in a `finally` in the
command `ExecuteAsync`, or via a `protected` disposal helper on this base). Treat
`ConfigureLogging` as call-once / idempotent and document that. At minimum capture and
dispose the previous logger if reconfiguration is genuinely intended.

**Resolution:** Resolved 2026-05-22 — `ConfigureLogging` is now idempotent (guarded by `_loggingConfigured` field) and disposes the previous `Log.Logger` before overwriting; a new `protected static FlushLogging()` helper calls `Log.CloseAndFlush()` for commands to call in their `finally` blocks; XML doc updated accordingly.

### Driver.Cli.Common-004

| Field | Value |
|---|---|
| Severity | Low |
| Category | Error handling & resilience |
| Location | `src/Drivers/Cli/ZB.MOM.WW.OtOpcUa.Driver.Cli.Common/SnapshotFormatter.cs:68-70` |
| Status | Resolved |

**Description:** `FormatTable` calls `rows.Max(r => r.Tag.Length)` (and the same for the
value and status columns) without guarding against empty input. When `tagNames` and
`snapshots` are both empty (equal length, so the mismatch check at line 56 passes),
`Enumerable.Max` throws `InvalidOperationException` ("Sequence contains no elements").
A batch read that legitimately returns zero tags therefore crashes the formatter
instead of producing an empty (header-only) table.

**Recommendation:** Short-circuit on `rows.Length == 0` (return just the header +
separator, or an explicit "no rows" line), or use `DefaultIfEmpty(0).Max(...)` for the
width computations.

**Resolution:** Resolved 2026-05-23 — `FormatTable` guards each `rows.Max(...)` width
computation with a `rows.Length == 0 ? "<HEADER>".Length : Math.Max(...)` ternary, so
an empty batch read returns the header + separator rows (no data rows) instead of
throwing `InvalidOperationException`. The fix was landed in commit `1433a1c` alongside
the -002 work, and the regression test
`SnapshotFormatterTests.FormatTable_with_empty_input_returns_header_only` (added under
-005) exercises it.

### Driver.Cli.Common-005

| Field | Value |
|---|---|
| Severity | Medium |
| Category | Testing coverage |
| Location | `tests/Drivers/Cli/ZB.MOM.WW.OtOpcUa.Driver.Cli.Common.Tests/SnapshotFormatterTests.cs:27-37` |
| Status | Resolved |

**Description:** The `FormatStatus_names_well_known_status_codes` `[Theory]` asserts
`0x80060000 => "BadTimeout"`, which encodes the wrong spec value (see
Driver.Cli.Common-001). The test passes because it validates the formatter against the
same incorrect table, so the bug is invisible to CI. Additionally there is no coverage
for: `DriverCommandBase` (`ConfigureLogging` verbose vs non-verbose level selection — no
test exercises the base at all), `FormatTable` with empty input (Driver.Cli.Common-004
would have been caught), `FormatValue` with array / enum / custom `object` values, and
`FormatTimestamp` with `DateTimeKind.Unspecified` (the docs imply Unspecified is
normalised but only `Local` is tested).

**Recommendation:** Fix the `[Theory]` expectations once Driver.Cli.Common-001 is
resolved, and add a test asserting each shortlist entry against the OPC Foundation
`Opc.Ua.StatusCodes` constants so the table cannot silently drift. Add `FormatTable`
empty-input and `DriverCommandBase` level-selection tests.

**Resolution:** Resolved 2026-05-22 — added `FormatTable_with_empty_input_returns_header_only` (exercises the -004 fix), `FormatStatus_with_sub_code_bits_resolves_to_named_class` / `FormatStatus_unknown_sub_code_falls_back_to_severity_class` Theories (cover -002 fix), and a new `DriverCommandBaseTests` class with four tests covering verbose/non-verbose level selection, idempotency of `ConfigureLogging`, and `FlushLogging`; stale `FormatStatus_unknown_codes_fall_back_to_hex_only` expectation corrected to match the -002 severity-class fallback.

### Driver.Cli.Common-006

| Field | Value |
|---|---|
| Severity | Low |
| Category | Documentation & comments |
| Location | `src/Drivers/Cli/ZB.MOM.WW.OtOpcUa.Driver.Cli.Common/SnapshotFormatter.cs:71`, `src/Drivers/Cli/ZB.MOM.WW.OtOpcUa.Driver.Cli.Common/DriverCommandBase.cs:9` |
| Status | Resolved |

**Description:** Two minor doc inaccuracies. (1) The comment at `SnapshotFormatter.cs:71`
states the "source-time column is fixed-width (ISO-8601 to ms) so no max-measurement
needed" — true only when every snapshot has a non-null `SourceTimestampUtc`.
`FormatTimestamp` returns `"-"` for a null timestamp, so a mixed table has a 1-char-wide
cell in an otherwise 24-char column; the column is unaligned. Harmless (right-most, no
padding consumer) but the stated invariant does not hold. (2) The `DriverCommandBase`
class summary enumerates "Modbus / AB CIP / AB Legacy / S7 / TwinCAT" as the driver CLIs
but omits FOCAS, which `docs/DriverClis.md` lists as the sixth CLI built on this shared
library. The XML doc is stale relative to the shipped driver-CLI set.

**Recommendation:** Reword the `SnapshotFormatter.cs:71` comment to note the column is
right-most and intentionally unpadded rather than claiming fixed width. Add FOCAS to the
`DriverCommandBase` class-summary driver list.

**Resolution:** Resolved 2026-05-23 — (1) `SnapshotFormatter.cs:71` comment reworded
to state the source-time column is the right-most one and intentionally not
measured/padded, calling out the null-timestamp `"-"` case explicitly. (2) FOCAS was
added to the `DriverCommandBase` class-summary driver enumeration in commit `7ff356b`
(landed alongside the -003 work).

### Driver.Cli.Common-007

| Field | Value |
|---|---|
| Severity | High |
| Category | Correctness & logic bugs |
| Location | `src/Drivers/Cli/ZB.MOM.WW.OtOpcUa.Driver.Cli.Common/SnapshotFormatter.cs:129` |
| Status | Resolved |

**Description:** Commit `5a9c459` added `0x80550000u => "BadDeviceFailure"` to the
`FormatStatus` shortlist, but `0x80550000` is the canonical OPC UA spec value for
`BadSecurityPolicyRejected`, not `BadDeviceFailure`. The correct spec value for
`BadDeviceFailure` is `0x808B0000` (verified against the OPC Foundation
`Opc.Ua.StatusCodes` table via DeepWiki; corroborated locally by
`src/Drivers/ZB.MOM.WW.OtOpcUa.Driver.Galaxy/Runtime/StatusCodeMap.cs:40`
(`BadDeviceFailure = 0x808B0000u`) and the two Wonderware historian quality mappers,
which all hand-pin the correct value).

This is the same shape of bug Driver.Cli.Common-001 closed: a wrong hex literal
in the shortlist that the test theory (`SnapshotFormatterTests.cs:42`) blindly
asserts against the same wrong value, so the bug is invisible to CI.

Practical impact, two-sided:
1. A driver that returns the real spec `BadDeviceFailure` (`0x808B0000`) — e.g.
   the `Driver.Galaxy.StatusCodeMap` path on a deploy-time device fault — falls
   through the named shortlist entirely. Since Driver.Cli.Common-002 added the
   severity-class fallback, it now renders as `0x808B0000 (Bad)` instead of
   `0x808B0000 (BadDeviceFailure)` — operators lose the specific class label
   `docs/Driver.FOCAS.Cli.md:153` tells them to read off the output.
2. A driver that returns `0x80550000` (which `FocasStatusMapper`, `AbCipStatusMapper`,
   `AbLegacyStatusMapper`, `TwinCATStatusMapper`, `S7Driver`, and `ModbusDriver` all
   misuse as "BadDeviceFailure") now renders as `0x80550000 (BadDeviceFailure)` —
   matching driver intent but contradicting the OPC UA spec, which says any client
   that decodes the same payload using the OPC Foundation stack will see
   `BadSecurityPolicyRejected`. A security-monitoring tool keying on
   `BadSecurityPolicyRejected` will fire on a CPU fault, while real
   `BadSecurityPolicyRejected` returns from the secure-channel layer would be
   mislabelled as a device fault. Operator-facing CLI output and machine-readable
   status semantics disagree.

The deeper bug is the wrong constant in the native-protocol mappers (out of scope
for this module), but the `SnapshotFormatter` shortlist is its own
spec-authoritative reference point — Driver.Cli.Common-001 explicitly framed the
shortlist as canonical, with the in-line "keep [these literals] in sync with [the
Opc.Ua.StatusCodes] table" comment at `SnapshotFormatter.cs:112-113`. That
contract is now broken.

**Recommendation:** Change line 129 to `0x808B0000u => "BadDeviceFailure"`. Update
the matching `[InlineData]` rows in `SnapshotFormatterTests.cs` (line 42 in the
well-known Theory; line 60 in the redundant Theory — see Driver.Cli.Common-008).
Also note in the resolution that the native-protocol mappers (FOCAS / AbCip /
AbLegacy / TwinCAT / S7 / Modbus) need the same fix recorded against their own
module reviews — the constant `0x80550000` should be replaced with `0x808B0000`
everywhere it claims to mean `BadDeviceFailure`. Consider Driver.Cli.Common-001's
original recommendation again: add a CI test that cross-checks every shortlist
entry against `Opc.Ua.StatusCodes` reflection so this class of bug stops
recurring.

**Resolution:** Resolved 2026-05-23 — corrected `SnapshotFormatter.FormatStatus`
to map `0x808B0000u => "BadDeviceFailure"` (was `0x80550000u`). Updated the
`InlineData` row in the well-known Theory accordingly; the redundant native-
emitted Theory was deleted entirely per Driver.Cli.Common-008. Added a regression
row to `FormatStatus_does_not_apply_pre_fix_wrong_names` pinning that
`0x80550000` no longer renders as `BadDeviceFailure` (mirroring the
Driver.Cli.Common-001 wrong-name guards). The underlying constant was also
corrected in all six native-protocol mappers as part of the same commit:
`FocasStatusMapper.BadDeviceFailure`, `AbCipStatusMapper.BadDeviceFailure`,
`AbLegacyStatusMapper.BadDeviceFailure`, `TwinCATStatusMapper.BadDeviceFailure`,
`ModbusDriver.StatusBadDeviceFailure`, `S7Driver.StatusBadDeviceFailure` — all
moved from `0x80550000u` to `0x808B0000u`. The three downstream Modbus tests
(`ModbusExceptionMapperTests` 3 InlineData rows + 1 ShouldBe assertion;
`ExceptionInjectionTests.StatusBadDeviceFailure` constant) updated to expect
the corrected code. **Behavior change:** OPC UA clients consuming the native
drivers now see the canonical `BadDeviceFailure` (0x808B0000) instead of the
misnamed `BadSecurityPolicyRejected` (0x80550000) on device-fault paths —
operator-facing CLI output and machine-readable status semantics now agree.
Suite totals after fix: Driver.Cli.Common.Tests 43 green (was 48 — minus 5
redundant rows); Modbus.Tests 263; AbCip.Tests 262; AbLegacy.Tests 157;
FOCAS.Tests 178; S7.Tests 112; TwinCAT.Tests 131; all green. The Opc.Ua.StatusCodes
cross-check the recommendation suggested is recorded as a follow-up worth
considering but is out of scope for this fix.

### Driver.Cli.Common-008

| Field | Value |
|---|---|
| Severity | Low |
| Category | Testing coverage |
| Location | `tests/Drivers/Cli/ZB.MOM.WW.OtOpcUa.Driver.Cli.Common.Tests/SnapshotFormatterTests.cs:50-64` |
| Status | Resolved |

**Description:** Commit `5a9c459` adds a new
`FormatStatus_names_native_driver_emitted_codes` `[Theory]` whose five
`[InlineData]` rows are identical to five rows added to the existing
`FormatStatus_names_well_known_status_codes` `[Theory]` in the same commit
(lines 32, 39, 40, 41, 42). The new Theory therefore adds no coverage. It is
also weaker than the Theory it duplicates: it asserts
`output.ShouldContain($"({expectedName})")` (substring match) where the
well-known Theory asserts `output.ShouldBe($"0x{status:X8} ({expectedName})")`
(exact match including the hex prefix). The substring form would not catch a
regression where the hex literal renders wrong but the name is correct.

This is not a correctness problem — both Theories pass — but it's a
copy-paste inconsistency that costs maintainer attention every time someone
reads the test file and wonders which Theory is authoritative.

**Recommendation:** Either (a) delete the new Theory entirely — its five rows
are already covered by the well-known Theory in the same commit — or (b) keep
it but switch to `ShouldBe($"0x{status:X8} ({expectedName})")` so its
assertion strength matches the rest of the file. Option (a) is cleaner: the
commit's "operator workflow" intent is documented well enough in the
well-known Theory comment block; the redundant Theory is dead weight.

**Resolution:** Resolved 2026-05-23 — took option (a): deleted the
`FormatStatus_names_native_driver_emitted_codes` Theory entirely. Its five
`InlineData` rows are covered by the well-known Theory's `ShouldBe` (strict
exact-match assertion), which is the authoritative shortlist test. Landed
alongside the Driver.Cli.Common-007 fix in the same commit.

---

## Re-review 2026-06-19 (commit `7286d320`)

Delta scope since `a9be809`:

- `a6ae4e22` — `fix(status-codes)`: corrected `BadDeviceFailure` from
  `0x80550000` to `0x808B0000` in `FormatStatus` and all six native-protocol
  mappers (Driver.Cli.Common-007); deleted the redundant `FormatStatus_names_native_driver_emitted_codes`
  Theory (Driver.Cli.Common-008). Both already Resolved.
- `2b811477` — `chore(build)`: stripped inline `Version` attributes from
  `PackageReference` elements and centralised them in `Directory.Packages.props`.
  No logic change.
- `64e3fbe0` — `docs`: XML documentation backfilled on all previously-undocumented
  public members (`<summary>`, `<param>`, `<returns>`, `<inheritdoc/>` where
  applicable). No logic change; `CS1591` suppression in the csproj retained (the
  `NoWarn` suppression now acts as a belt-and-suspenders guard rather than primary
  silence).

Review covered all 10 categories.  Two new findings recorded (both Low).

| # | Category | Result |
|---|---|---|
| 1 | Correctness & logic bugs | Driver.Cli.Common-009 |
| 2 | OtOpcUa conventions | No issues found |
| 3 | Concurrency & thread safety | No issues found |
| 4 | Error handling & resilience | No issues found |
| 5 | Security | No issues found |
| 6 | Performance & resource management | No issues found |
| 7 | Design-document adherence | No issues found |
| 8 | Code organization & conventions | No issues found |
| 9 | Testing coverage | Driver.Cli.Common-010 |
| 10 | Documentation & comments | No issues found |

Both findings were fixed in-session (TDD: tests first, then src change).  Suite
went from 43 → 49 tests; build clean.

### Driver.Cli.Common-009

| Field | Value |
|---|---|
| Severity | Low |
| Category | Correctness & logic bugs |
| Location | `src/Drivers/Cli/ZB.MOM.WW.OtOpcUa.Driver.Cli.Common/SnapshotFormatter.cs:159-161` |
| Status | Resolved |

**Description:** After the named-shortlist match and the severity-class fallback
that were introduced by Driver.Cli.Common-002, `name` can never be `null` at the
`return` statement — the severity fallback switch unconditionally assigns one of
`"Good"`, `"Uncertain"`, or `"Bad"`.  The surviving `name is null` ternary therefore
has a dead branch: the bare-hex path (`$"0x{statusCode:X8}"` with no parenthesised
label) is unreachable.  This is misleading to readers: it implies there exists a
code path where neither the named shortlist nor the severity fallback produce a
label, which is false.  No correctness impact in practice, but it contradicts the
invariant the -002 fix established (operators always see a quality label) and could
confuse a future maintainer who extends the shortlist and thinks they need to handle
the `null` case explicitly.

**Recommendation:** Remove the dead ternary; replace with a direct
`return $"0x{statusCode:X8} ({name})";` and add a clarifying comment that `name`
is always non-null at this point (assigned by shortlist or fallback).  Pin a
regression `[Theory]` test asserting every output includes a `"("` so future edits
cannot accidentally reintroduce the bare-hex path.

**Resolution:** Resolved 2026-06-19 — removed the dead `name is null` ternary in
`FormatStatus`; replaced with `return $"0x{statusCode:X8} ({name})";` plus a
comment explaining the invariant.  Regression test
`FormatStatus_always_includes_parenthesised_label` (5-row `[Theory]`) added to
`SnapshotFormatterTests.cs` to pin the guarantee.

### Driver.Cli.Common-010

| Field | Value |
|---|---|
| Severity | Low |
| Category | Testing coverage |
| Location | `src/Drivers/Cli/ZB.MOM.WW.OtOpcUa.Driver.Cli.Common/SnapshotFormatter.cs:167-172` / `tests/Drivers/Cli/ZB.MOM.WW.OtOpcUa.Driver.Cli.Common.Tests/SnapshotFormatterTests.cs` |
| Status | Resolved |

**Description:** `FormatTimestamp` converts `DateTime` values whose `Kind` is not
`DateTimeKind.Utc` via `ToUniversalTime()`.  For `DateTimeKind.Local` this is
correct and tested (`FormatTimestamp_normalises_local_kind_to_utc`).  However,
`DateTimeKind.Unspecified` is a valid `Kind` produced by, e.g., EF-materialized
timestamps or unconfigured driver clocks; `ToUniversalTime()` treats `Unspecified`
identically to `Local` (documented .NET behavior).  The test suite never exercises
this case.  The behavior is correct per OPC UA conventions (unspecified → assume
local → convert to UTC), but the gap was noted in Driver.Cli.Common-005's description
and was never closed during the -005 resolution commit.  Without the test, a future
refactor of the `Kind` branch could silently drop `Unspecified` conversion and no
test would catch it.

**Recommendation:** Add a `[Fact]` asserting that a `DateTimeKind.Unspecified`
timestamp also produces a `"Z"`-suffixed output string, documenting the
"treat Unspecified as Local" contract.

**Resolution:** Resolved 2026-06-19 — added
`FormatTimestamp_treats_unspecified_kind_as_local_and_converts_to_utc` to
`SnapshotFormatterTests.cs`, asserting that a `DateTimeKind.Unspecified` value
produces a `"Z"`-suffixed ISO-8601 string.  No source change needed (behavior was
already correct).
