[BUG] Thermostat Server cluster has no dedicated unit tests

[lboue]

Summary

The Thermostat Server cluster (src/app/clusters/thermostat-server/) currently has no dedicated unit tests. This gap was surfaced by a Codecov patch coverage report on PR #43583 which added a call to MatterReportingAttributeChangeCallback inside SetActivePreset.
Coverage was 0% for that path because no test exercises it.

Affected files

• src/app/clusters/thermostat-server/thermostat-server.cpp
• src/app/clusters/thermostat-server/thermostat-server-presets.cpp
• src/app/clusters/thermostat-server/thermostat-server-atomic.cpp
• src/app/clusters/thermostat-server/thermostat-server-suggestions.cpp

What is missing

Area	Examples of untested paths
SetActivePreset	success path, invalid handle, no delegate
CommitPendingPresets	success, delegate error
Atomic write	begin / commit / rollback
Suggestions	append, remove, re-evaluate
Read / Write attribute access	preset-related attributes

Suggested fix

A first test file was introduced in PR #43585 to cover the SetActivePreset success path. It can serve as a starting point for broader coverage.

The test infrastructure (delegate mock, stubs for ZAP-generated accessors) needed to compile thermostat server sources in the app test suite is also already set up by that PR.

References

• PR adding first test: [Tests] Add unit tests for Thermostat Server Presets functionality #43585

Reproduction steps

Tests missing

Bug prevalence

always

GitHub hash of the SDK that was being used

N/A

Platform

linux

Platform Version(s)

No response

Anything else?

No response