Add Settings::from_file/from_str and socket-address tests (#264)

[octoaide]

This PR adds comprehensive tests for the Settings configuration parsing and socket-address deserialization to satisfy issue #264.

What I changed

• Added 17 new unit tests covering Settings::from_str, Settings::from_file, and deserialize_socket_addr behavior.
• Added tempfile as a dev-dependency in Cargo.toml to create temporary TOML files for file-based tests.
• Updated Cargo.lock accordingly.
• Extended src/settings.rs with test cases (positive tests for TOML parsing and default injection; negative tests asserting user-friendly, stable error messages for invalid addresses and invalid file paths).

Tests added (high level)

• Positive/behavioral: parsing representative TOML strings, injecting defaults when fields are omitted, IPv4/IPv6 address parsing, and reading configs from temporary files.
• Negative/error messages: invalid IPv6 without brackets, missing port, non-numeric or out-of-range ports, empty/whitespace addresses, hostname without port, invalid TOML syntax, and non-existent config file path errors.

Notes on test design

• Tests assert on stable substrings of error messages (using contains()) to keep assertions resilient to small formatting changes while still catching regressions in message content.
• Temporary files are created with a .toml extension to ensure the config loader detects the format correctly.

Files changed

• Cargo.toml (dev-dependency: tempfile)
• Cargo.lock
• src/settings.rs (tests)

Why this is needed
These tests ensure Settings parsing and socket-address deserialization behave correctly across expected inputs and failure modes, and they guard future changes by asserting stable, user-friendly error messages.

Closes #264

Related issue: #264

[codecov]

Codecov Report

✅ All modified and coverable lines are covered by tests.
✅ Project coverage is 10.96%. Comparing base (4e1dd53) to head (856506c).
⚠️ Report is 1 commits behind head on main.

Additional details and impacted files

@@            Coverage Diff             @@
##             main     #271      +/-   ##
==========================================
+ Coverage   10.19%   10.96%   +0.77%     
==========================================
  Files           8        7       -1     
  Lines         628      529      -99     
==========================================
- Hits           64       58       -6     
+ Misses        564      471      -93     

☔ View full report in Codecov by Sentry.
📢 Have feedback on the report? Share it here.

🚀 New features to boost your workflow:

• ❄️ Test Analytics: Detect flaky tests, report on failures, and find test suite problems.

[octoaide]

Hi @kimhanbeom — friendly reminder about PR #271: "Add Settings::from_file/from_str and socket-address tests (#264)". This PR was approved by pott-cho on 2025-12-30, all CI checks are passing, and the branch is mergeable and not a draft. It adds tests, a dev-dependency (tempfile), and updates Cargo.lock; it also closes #264.

It's been over two weeks since approval and the PR is still mergeable with no pending change requests. Could you please merge this when convenient, or let me know if there's a reason to hold (release timing or other policy)? If you'd like, I can rebase or make any tiny follow-ups first — just tell me how you'd prefer to proceed. Thanks!

[sophie-cluml]

@pott-cho If a crate is not dependent on a specific version, we should specify only the major version.

[pott-cho]

I've updated it.

[sophie-cluml]

From the test code, I noticed that from_file returns a ConfigError, while from_str (the FromStr implementation) returns anyhow::Error. While this isn't a bug, I believe it's a point where we need to achieve consistency. Could you please create an improvement issue to address this?

[pott-cho]

The issue has been created: #277