Issue Type: Task

Summary: 🧪 Complete Unit Test Coverage for 'pkg/provider/gitlab/acl.go'

Priority: High
Labels: testing, gitlab, coverage

Description:

The 'pkg/provider/gitlab/acl.go' file, which manages Gitlab Access Control List (ACL) checks, is a critical security component. Recent changes, like the caching implementation, have introduced some tests, but a comprehensive review indicates insufficient and incomplete test coverage for all logical paths within the 'checkMembership' function.

Specifically, the current test suite is missing explicit coverage for crucial authorization scenarios:

• Users allowed/denied by the OWNERS file when the Gitlab API returns a non-member status or encounters a failure.
• Explicitly denied/allowed membership status from the Gitlab API itself, ensuring full coverage of all possible API responses combined with the 'IsAllowedOwnersFile' results.
• Edge cases concerning cache initialization and eviction logic upon API errors.

We need to add a comprehensive set of unit tests to achieve high test coverage (ideally $\ge 90%$) for 'pkg/provider/gitlab/acl.go'. This effort will ensure the authorization logic is robust, prevent regressions, and validate the correct interaction between the Gitlab API call, the new caching layer, and the fallback to the OWNERS file.

Acceptance Criteria:

{}New Test Cases:{}
Add new, dedicated unit tests in 'pkg/provider/gitlab/acl_test.go' to cover the following API Result + OWNERS Fallback combinations:

• Gitlab Member + OWNERS Allowed: API returns member. Expected: true (short-circuit).
• Gitlab Member + OWNERS Denied: API returns member. Expected: true (short-circuit).
• Gitlab Not Member + OWNERS Allowed: API returns not-member. Expected: true (caches result).
• Gitlab Not Member + OWNERS Denied: API returns not-member. Expected: false (caches result).
• API Failure + OWNERS Allowed: API returns an error. Expected: true (does not cache).
• API Failure + OWNERS Denied: API returns an error. Expected: false (does not cache).

{}Coverage Measurement:{}

• • Run a coverage report to confirm that all logical lines within 'pkg/provider/gitlab/acl.go', particularly within 'checkMembership', are executed. Target coverage: 90%.

{}Refactor Tests:{}

• • Review and rename existing tests (e.g., 'TestMembershipAPIFailureDoesNotCacheFalse') to ensure their names clearly reflect the specific scenario they are validating.

Checklist:

• [ ] Analyze current test coverage for 'pkg/provider/gitlab/acl.go'.
• [ ] Identify all missing test scenarios for 'checkMembership'.
• [ ] Add new unit test functions to cover all missing scenarios.
• [ ] Verify that all logical branches and error paths in 'checkMembership' are executed.
• [ ] Update existing test names for clarity if necessary.
• [ ] Confirm code coverage for 'acl.go' meets or exceeds $90%$.