fix: Adjust swagger redirects

[schloerke]

Summary

This PR adds comprehensive unit tests for the swagger redirect functionality that was fixed in the recent commit addressing issue #1016.

Changes

New Test File

• tests/testthat/test-swagger-redirects.R (417 lines, 39 tests)
  • Tests redirect structure with default and custom apiPath
  • Tests redirect handlers return correct 301 status codes
  • Tests integration with plumber routers
  • Tests mounting/unmounting behavior
  • Tests edge cases (nested paths, env variables, empty paths)

Updated Test Files

• tests/testthat/test-ui-apipath.R
  • Updated existing swagger_redirects test to match new relative path behavior

Test Coverage

The new tests verify:

1. Basic Redirect Functionality

   • Correct redirect structure generation
   • Custom apiPath handling
   • Disabled redirects when plumber.legacyRedirects = FALSE

2. Redirect Handlers

   • 301 permanent redirect status codes
   • Relative path redirects (../__docs__/) instead of absolute paths
   • Proper handler execution with mock requests/responses

3. Router Integration

   • Redirects properly mounted on plumber routers
   • Correct behavior with various apiPath configurations (empty, /api/v1, nested)
   • Full request routing through redirect endpoints

4. Unmounting & Cleanup

   • Proper cleanup when docs are unmounted
   • Overwrite warnings when routes conflict

5. Edge Cases

   • Nested apiPath values (/api/v1/myapp)
   • Environment variable support (PLUMBER_APIPATH)
   • Empty apiPath handling
   • Multiple independent redirects on same router

Implementation Details

The redirect implementation uses:

• Redirect keys that include the apiPath prefix (e.g., /api/v2/__swagger__/)
• Relative path targets (../__docs__/) to ensure redirects work correctly regardless of apiPath configuration
• This approach works seamlessly with RStudio Connect and other hosting environments

Test Results

All 39 tests pass successfully:

✔ | F W S  OK | Context
✔ |        39 | Swagger redirects

══ Results ═════════════════════════════════════════════════
Duration: 0.8 s

[ FAIL 0 | WARN 0 | SKIP 0 | PASS 39 ]

Integration Verification

Verified the redirects work correctly on a live plumber app:

# With default apiPath
Endpoints: /__swagger__/, /__swagger__/index.html
Redirect: 301 → ../__docs__/

# With custom apiPath (/api/v2)
Endpoints: /api/v2/__swagger__/, /api/v2/__swagger__/index.html
Redirect: 301 → ../__docs__/

Related Issues

• Fixes apiPath + redirect breaks default documentation behavior on connect #1016
• Related fix: Actually use apiPath when mounting the docs #977 / global basepath #836

Checklist

• Added comprehensive unit tests
• All tests pass locally
• Updated existing tests to match new behavior
• Verified integration with working plumber apps
• Tests cover edge cases and various configurations