test: add e2e tests to validate customHeaders of trafficManagerProfile

[Copilot]

This PR adds comprehensive end-to-end tests to validate that customHeaders in TrafficManagerProfile specifications are properly propagated to Azure Traffic Manager profiles.

Changes Made

1. Updated buildDesiredATMProfile helper function

Added support for customHeaders in the test helper function to mirror the controller implementation:

// Add custom headers if specified
if len(monitorConfig.CustomHeaders) > 0 {
    customHeaders := make([]*armtrafficmanager.MonitorConfigCustomHeadersItem, 0, len(monitorConfig.CustomHeaders))
    for _, header := range monitorConfig.CustomHeaders {
        customHeaders = append(customHeaders, &armtrafficmanager.MonitorConfigCustomHeadersItem{
            Name:  ptr.To(header.Name),
            Value: ptr.To(header.Value),
        })
    }
    res.Properties.MonitorConfig.CustomHeaders = customHeaders
}

2. Added new e2e test case

Added a comprehensive test case "Updating the trafficManagerProfile with customHeaders" that validates:

• Setting customHeaders: Tests adding custom headers to a TrafficManagerProfile and verifying they appear in the Azure Traffic Manager profile
• Updating customHeaders: Tests modifying existing custom headers and validating the changes
• Removing customHeaders: Tests removing all custom headers and ensuring they're cleared from the Azure profile

Test Coverage

The new test covers the complete lifecycle of customHeaders:

// Test 1: Add customHeaders
profile.Spec.MonitorConfig.CustomHeaders = []fleetnetv1beta1.MonitorConfigCustomHeader{
    {Name: "X-Custom-Header-1", Value: "custom-value-1"},
    {Name: "X-Custom-Header-2", Value: "custom-value-2"},
}
// Validate propagation to Azure Traffic Manager

// Test 2: Update customHeaders  
profile.Spec.MonitorConfig.CustomHeaders = []fleetnetv1beta1.MonitorConfigCustomHeader{
    {Name: "X-Modified-Header", Value: "modified-value"},
}
// Validate changes are applied

// Test 3: Remove customHeaders
profile.Spec.MonitorConfig.CustomHeaders = nil
// Validate headers are removed

Implementation Details

• Follows existing test patterns and integrates seamlessly with the "Test updating trafficManagerProfile" context
• Uses the same validation framework (atmValidator.ValidateProfile) as other tests
• Implementation exactly mirrors the controller logic in generateAzureTrafficManagerProfile
• Only adds 59 lines with no deletions - surgical, minimal changes

This ensures that the customHeaders feature is thoroughly tested end-to-end, validating proper propagation from Kubernetes TrafficManagerProfile resources to actual Azure Traffic Manager profiles.

Fixes #313.

---

E2E tests

https://github.com/Azure/fleet-networking/actions/runs/15344659627 are green

[codecov]

Codecov Report

All modified and coverable lines are covered by tests ✅

Project coverage is 80.58%. Comparing base (b804959) to head (9837420).
Report is 2 commits behind head on main.

Additional details and impacted files

@@            Coverage Diff             @@
##             main     #314      +/-   ##
==========================================
- Coverage   80.61%   80.58%   -0.04%     
==========================================
  Files          29       29              
  Lines        4153     4161       +8     
==========================================
+ Hits         3348     3353       +5     
- Misses        641      643       +2     
- Partials      164      165       +1     

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[Copilot]

Just as a heads up, I was blocked by some firewall rules while working on your feedback. Expand below for details.

Warning

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