test: improve test core feature test coverage

[YasharF]

Checklist

• I acknowledge that submissions that include copy-paste of AI-generated content taken at face value (PR text, code, commit message, documentation, etc.) most likely have errors and hence will be rejected entirely and marked as spam or invalid
• I manually tested the change with a running instance, DB, and valid API keys where applicable
• Added/updated tests if the existing tests do not cover this change
• README or other relevant docs are updated
• --no-verify was not used for the commit(s)
• npm run lint passed locally without any errors
• npm test passed locally without any errors
• npm run test:e2e:replay passed locally without any errors
• npm run test:e2e:custom -- --project=chromium-nokey-live passed locally without any errors
• PR diff does not include unrelated changes
• PR title follows Conventional Commits — https://www.conventionalcommits.org/en

Description

• Added unit tests for better coverage of core functions in controllers/user.js and config/passport.js
• Removed redundant test file test/auth.opt.test.js

Screenshots of UI changes (browser) and logs/test results (console, terminal, shell, cmd)

[Copilot]

Pull request overview

This PR increases unit test coverage for core authentication and user-account flows, focusing on controllers/user.js and config/passport.js, and removes a redundant OAuth test file.

Changes:

• Expanded test/user.test.js to cover many user controller flows (login, signup, 2FA, unlinking, password reset, etc.).
• Expanded test/passport.test.js to cover isAuthenticated, (de)serialization, and LocalStrategy behavior.
• Removed test/auth.opt.test.js and updated test/TESTING.md to reflect the current test suite layout.

Reviewed changes

Copilot reviewed 4 out of 4 changed files in this pull request and generated 3 comments.

File	Description
test/user.test.js	Adds extensive controller unit tests, including require-shim-based dependency stubbing.
test/passport.test.js	Adds middleware and strategy unit tests for config/passport.js.
test/auth.opt.test.js	Deletes a redundant OAuth token-saving test suite.
test/TESTING.md	Updates test tree documentation to match current test files.

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[Copilot]

Pull request overview

Copilot reviewed 6 out of 6 changed files in this pull request and generated 4 comments.

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[Copilot]

Pull request overview

Copilot reviewed 7 out of 7 changed files in this pull request and generated no new comments.

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