Improvement: Increase unit test coverage to 90% line + branch: `score/TimeSlave/`

[lavrovvalera]

What

Reach 90% line coverage and 90% branch coverage for the score/TimeSlave/
component once its implementation is available (see epic
eclipse-score/score#2691).

Steps:

1. Generate a per-component coverage report locally:

   bazel coverage --config=time-x86_64-linux //score/TimeSlave/...
   genhtml --branch-coverage bazel-out/_coverage/_coverage_report.dat -o coverage-report/
   

2. Identify files and branches below 90%
3. Add missing unit tests — focus areas:
   • IPC channel (libTSClient) — connection, disconnection, error paths
   • PTP sync loop — synchronization state transitions
   • clock_adjtime / clock_settime integration — stub/mock the syscall
   • TimeSlave process lifecycle — start, stop, restart

References

• TimeSlave implementation epic: eclipse-score/score#2691
• S-CORE process (Coverage section):
  https://github.com/eclipse-score/score/blob/main/docs/contribute/development/cpp/code_analysis.rst

Depends on

TimeSlave implementation (eclipse-score/score#2691) must be sufficiently
complete before this task can begin.

Estimates for realization

M - Week

Category

• Affects Detailed Design

Requirements / Architecture

• Requirements / Architecture are not affected by this change?