Add test for cli/admin_timer

[bowenxia]

What changed?

• Add test for cli/admin_timer
• Refactor fmt.print to use ioHandler for a better testability

Why?
code coverage week

How did you test it?
unti test

Potential risks

Release notes

Documentation Changes

[codecov]

Codecov Report

Attention: Patch coverage is 83.33333% with 2 lines in your changes missing coverage. Please review.

Project coverage is 79.77%. Comparing base (a7ce2f6) to head (e3d1dee).
Report is 4 commits behind head on master.

Files with missing lines	Patch %	Lines
tools/cli/admin_timers.go	77.77%	1 Missing and 1 partial ⚠️

Additional details and impacted files

Files with missing lines	Coverage Δ
tools/cli/histogram.go	100.00% <100.00%> (ø)
tools/cli/admin_timers.go	78.60% <77.77%> (+78.60%)	⬆️

... and 12 files with indirect coverage changes

---

Continue to review full report in Codecov by Sentry.

Legend - Click here to learn more
Δ = absolute <relative> (impact), ø = not affected, ? = missing data
Powered by Codecov. Last update a7ce2f6...e3d1dee. Read the comment docs.