[codex] improve unit test coverage

[abtreece]

Summary

• add explicit unit, coverage, and race Make targets
• add reload manager tests for subscriber notification and non-blocking triggers
• expand detailed health coverage for metrics, env, types, DynamoDB, SSM, and Secrets Manager

Testing

• go test ./pkg/...
• make unit
• go test -race ./pkg/service ./pkg/metrics ./pkg/backends/dynamodb ./pkg/backends/ssm ./pkg/backends/secretsmanager ./pkg/backends/types
• git diff --check

Notes

Coverage across ./pkg/... improved from 76.0% to 78.7%.

[codecov]

Codecov Report

✅ All modified and coverable lines are covered by tests.
✅ Project coverage is 70.83%. Comparing base (5a4adc2) to head (819e212).

Additional details and impacted files

@@            Coverage Diff             @@
##             main     #600      +/-   ##
==========================================
+ Coverage   67.43%   70.83%   +3.40%     
==========================================
  Files          53       53              
  Lines        5644     5644              
==========================================
+ Hits         3806     3998     +192     
+ Misses       1612     1418     -194     
- Partials      226      228       +2     

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[Copilot]

Pull request overview

This PR focuses on improving confidence in confd by expanding unit test coverage across the reload manager, metrics health endpoints, and multiple backend detailed health checks, while also adding explicit Make targets for unit, coverage, and race testing.

Changes:

• Added Makefile targets for unit, coverage, and race test workflows.
• Added/expanded tests for reload notifications and non-blocking reload triggers.
• Expanded detailed health check test coverage across metrics and several backends (Env, DynamoDB, SSM, Secrets Manager, and shared types).

Reviewed changes

Copilot reviewed 9 out of 9 changed files in this pull request and generated 1 comment.

Show a summary per file

File	Description
Makefile	Adds explicit unit, coverage, and race targets for testing workflows.
pkg/service/reload_test.go	New tests validating reload manager subscription behavior and non-blocking triggers under concurrency.
pkg/metrics/health_test.go	Adds coverage for ReadyDetailedHandler success/error paths and fallback behavior.
pkg/metrics/backend_test.go	Adds tests for instrumented detailed health checks and Close() delegation behavior.
pkg/backends/types/noop_test.go	Adds JSON marshaling coverage for DurationMillis.
pkg/backends/env/client_test.go	Adds HealthCheckDetailed coverage for the env backend.
pkg/backends/dynamodb/client_test.go	Adds HealthCheckDetailed success/error test coverage for DynamoDB backend.
pkg/backends/ssm/client_test.go	Adds HealthCheckDetailed success/error test coverage for SSM backend.
pkg/backends/secretsmanager/client_test.go	Adds HealthCheckDetailed success/error test coverage for Secrets Manager backend.

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