fix: update codecov ignore pattern for tests directory

[rafaelvzago]

What type of PR is this?

• Bug Fix

What this PR does / why we need it:

This PR fixes the codecov ignore pattern in codecov.yml to properly exclude the tests/ directory from coverage calculations.

The Problem:

• The current ignore pattern "tests" does not properly match files under the tests directory
• When e2e test infrastructure code is added (e.g., debugcollector.go, cleaner.go), it gets included in coverage calculations
• These files have 0% coverage (by design - they're test utilities), causing overall coverage to drop
• Result: codecov/project check fails on PRs adding e2e utilities

The Solution:

• Update pattern from "tests" to "tests/**" for proper glob matching
• This properly excludes ALL files under the tests directory recursively
• E2E test infrastructure code will no longer affect coverage calculations

Impact:

• Resolves codecov failures for PR Enhance e2e debug information with artifact collection #1356 (and similar PRs)
• 28 out of 50 recent PRs (56%) have had codecov/project failures - this fixes the root cause
• Aligns with the project's intent to exclude test infrastructure from coverage

Testing:

• Created test branch merging this fix with PR Enhance e2e debug information with artifact collection #1356 changes
• Verified pattern correctly matches tests/e2e/util/debugcollector/debugcollector.go
• See CODECOV_INVESTIGATION_PR1356.md for full analysis

Which issue(s) this PR fixes:

Fixes #1356

Related Issue/PR #1356

Additional information:

This change follows codecov best practices for excluding directories from coverage. The glob pattern tests/** is the standard way to recursively exclude all files under a directory.

Evidence of systemic issue:

• Analysis of last 50 PRs shows 56% had codecov/project failures
• E2E utilities like cleaner.go have no unit tests (by design)
• These utilities use //go:build e2e tags and only run during e2e tests

Full investigation available in repository after merge.

[istio-testing]

Hi @rafaelvzago. Thanks for your PR.

I'm waiting for a istio-ecosystem or istio member to verify that this patch is reasonable to test. If it is, they should reply with /ok-to-test on its own line. Until that is done, I will not automatically test new commits in this PR, but the usual testing commands by org members will still work. Regular contributors should join the org to skip this step.

Once the patch is verified, the new status will be reflected by the ok-to-test label.

I understand the commands that are listed here.

Details

Instructions for interacting with me using PR comments are available here. If you have questions or suggestions related to my behavior, please file an issue against the kubernetes-sigs/prow repository.

[codecov]

Codecov Report

✅ All modified and coverable lines are covered by tests.
✅ Project coverage is 80.77%. Comparing base (fd7e684) to head (f2a5fcf).
⚠️ Report is 1 commits behind head on main.

Additional details and impacted files

@@            Coverage Diff             @@
##             main    #1357      +/-   ##
==========================================
+ Coverage   80.64%   80.77%   +0.13%     
==========================================
  Files          44       44              
  Lines        2299     2299              
==========================================
+ Hits         1854     1857       +3     
+ Misses        327      324       -3     
  Partials      118      118              

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[fjglira]

/ok-to-test

[fjglira]

lgtm

[bmangoen]

/cherry-pick release-1.28

[istio-testing]

@bmangoen: new pull request created: #1363

Details

In response to this:

/cherry-pick release-1.28

Instructions for interacting with me using PR comments are available here. If you have questions or suggestions related to my behavior, please file an issue against the kubernetes-sigs/prow repository.