test: keep the test suite headless

[davidberenstein1957]

Description

Two tests in tests/cli/test_cli_auth.py (test_authorize_raises_on_callback_error and test_authorize_raises_when_no_callback_received) called auth.authorize() without patching webbrowser.open, so running the test suite opened https://auth.example/authorize in the system browser. The PR adds an autouse fixture in tests/conftest.py that stubs webbrowser.open for every test. Tests that patch it explicitly, such as test_authorize_success, still take precedence.

Related Issue

Fixes #1424

Motivation and Context

Running the test suite should never open a browser tab. The two unpatched tests broke that expectation and could surprise anyone running tests locally or in CI.

How Has This Been Tested?

uv run pytest tests/cli: 74 passed.

Screenshots (if appropriate):

N/A

Types of changes

• Bug fix (non-breaking change which fixes an issue)
• New feature (non-breaking change which adds functionality)
• Breaking change (fix or feature that would cause existing functionality to change)

Docs/refactor/test only.

AI Usage Disclosure

• 🟥 AI-vibecoded: You cannot explain the logic. Car analogy : the car drive by itself, you are outside it and just tell it where to go.
• 🟠 AI-generated: Car analogy : the car drive by itself, you are inside and give instructions.
• ⭐ AI-assisted. Car analogy : you drive the car, AI help you find your way.
• ♻️ No AI used. Car analogy : you drive the car.

Checklist:

• My code follows the code style of this project.
• My change requires a change to the documentation.
• I have updated the documentation accordingly.
• I have read the docs/how-to/contributing.md document.
• I have added tests to cover my changes.
• All new and existing tests passed.

[codecov]

Codecov Report

✅ All modified and coverable lines are covered by tests.
✅ Project coverage is 91.69%. Comparing base (b64423c) to head (90d7e45).
⚠️ Report is 1 commits behind head on master.

Additional details and impacted files

@@           Coverage Diff           @@
##           master    #1425   +/-   ##
=======================================
  Coverage   91.69%   91.69%           
=======================================
  Files          49       49           
  Lines        5152     5152           
=======================================
  Hits         4724     4724           
  Misses        428      428           

☔ View full report in Codecov by Harness.
📢 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.
• 📦 JS Bundle Analysis: Save yourself from yourself by tracking and limiting bundle sizes in JS merges.

[inimaz]

Nice!