Add configurable certificate StoreLocation for certificate authentication

[Copilot]

Summary: Add StoreLocation selection for certificate authentication

Problem

Users were unable to select which certificate store location to use when authenticating with certificates. The code was hardcoded to use StoreLocation.CurrentUser, making it impossible to use certificates from StoreLocation.LocalMachine without writing custom request code.

Solution

Added a new configurable option CertificateStoreLocation that allows users to select between CurrentUser and LocalMachine when using certificate authentication from the certificate store.

Changes Made:

• Created CertificateStoreLocation enum with CurrentUser and LocalMachine options in all 5 HTTP modules
• Added CertificateStoreLocation property to Options classes with default value of CurrentUser (backward compatible)
• Updated GetCertificatesFromStore methods to accept and use the selected store location
• Updated error messages to indicate which store location was searched
• Successfully built all 5 modules with no errors
• Passed security review (CodeQL found 0 alerts)
• Bumped minor versions for all modules (non-breaking change)
• Added changelog entries for all modules
• Fixed DownloadFile tests to use MockHttp instead of external Wikipedia URL
• Added unit tests for CertificateStoreLocation feature and error cases
• Fixed failing test by using real HttpClientFactory to trigger certificate lookup exception
• Fixed whitespace formatting issues reported by superlinter
• Added additional tests for 80%+ code coverage

Version Updates:

• ✅ Frends.HTTP.Request: 1.5.0 → 1.6.0
• ✅ Frends.HTTP.SendBytes: 1.4.0 → 1.5.0
• ✅ Frends.HTTP.RequestBytes: 1.3.0 → 1.4.0
• ✅ Frends.HTTP.SendAndReceiveBytes: 1.3.0 → 1.4.0
• ✅ Frends.HTTP.DownloadFile: 1.3.0 → 1.4.0

Test Coverage Improvements:

Added new tests for:

• Empty URL validation (throws ArgumentNullException)

• CertificateStoreLocation.CurrentUser explicit test

• CertificateStoreLocation.LocalMachine with non-existent thumbprint (throws exception)

• Overwrite=false with existing file (throws exception)

• Authorization header deduplication

• WindowsAuthentication username validation

• Certificate from file with/without keyPhrase

• Certificate from string with keyPhrase

• Null headers handling

• Client caching behavior

• Basic auth with empty headers

• OAuth auth with empty headers

• Fixes Would like to be able to select StoreLocation when using Certificate #39

Original prompt

---

This section details on the original issue you should resolve

<issue_title>Would like to be able to select StoreLocation when using Certificate</issue_title>
<issue_description>Currently when making a request using certificate it only fetches certificates from StoreLocation.CurrentUser in Extensions.cs row 111.

We have a project where we need to be able to choose which StoreLocation the cert lives in. So the only solution here currently is to write the requests manually.</issue_description>

Comments on the Issue (you are @copilot in this section)

• Fixes Would like to be able to select StoreLocation when using Certificate #39

---

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[jefim]

@copilot Ok, now need to bump the versions (I think this is a non-breaking change, so second version number bump) and add changelog entries to correct files.

[Copilot]

@copilot Ok, now need to bump the versions (I think this is a non-breaking change, so second version number bump) and add changelog entries to correct files.

Done! Bumped minor versions for all 5 modules and added changelog entries with the new CertificateStoreLocation feature. Commit: 244982c

Version updates:

• Frends.HTTP.Request: 1.5.0 → 1.6.0
• Frends.HTTP.SendBytes: 1.4.0 → 1.5.0
• Frends.HTTP.RequestBytes: 1.3.0 → 1.4.0
• Frends.HTTP.SendAndReceiveBytes: 1.3.0 → 1.4.0
• Frends.HTTP.DownloadFile: 1.3.0 → 1.4.0

[jefim]

@copilot ok, unit tests fail now

Run dotnet test --collect:"XPlat Code Coverage"
dotnet test --collect:"XPlat Code Coverage"
shell: C:\Program Files\PowerShell\7\pwsh.EXE -command ". '{0}'"
env:
NUGET_SOURCE_URL: https://pkgs.dev.azure.com/frends-platform/frends-tasks/_packaging/test/nuget/v3/index.json
ROSLYNATOR_VERSION: 0.10.1
DOTNET_ROOT: C:\Program Files\dotnet
Determining projects to restore...
D:\a\Frends.HTTP\Frends.HTTP\Frends.HTTP.DownloadFile\Frends.HTTP.DownloadFile.Tests\Frends.HTTP.DownloadFile.Tests.csproj : warning NU1701: Package 'Pluralsight.Crypto 1.1.0' was restored using '.NETFramework,Version=v4.6.1, .NETFramework,Version=v4.6.2, .NETFramework,Version=v4.7, .NETFramework,Version=v4.7.1, .NETFramework,Version=v4.7.2, .NETFramework,Version=v4.8, .NETFramework,Version=v4.8.1' instead of the project target framework 'net6.0'. This package may not be fully compatible with your project. [D:\a\Frends.HTTP\Frends.HTTP\Frends.HTTP.DownloadFile\Frends.HTTP.DownloadFile.sln]
All projects are up-to-date for restore.
C:\Users\runneradmin.nuget\packages\system.security.cryptography.protecteddata\9.0.3\buildTransitive\netcoreapp2.0\System.Security.Cryptography.ProtectedData.targets(4,5): warning : System.Security.Cryptography.ProtectedData 9.0.3 doesn't support net6.0 and has not been tested with it. Consider upgrading your TargetFramework to net8.0 or later. You may also set true in the project file to ignore this warning and attempt to run in this unsupported configuration at your own risk. [D:\a\Frends.HTTP\Frends.HTTP\Frends.HTTP.DownloadFile\Frends.HTTP.DownloadFile\Frends.HTTP.DownloadFile.csproj::TargetFramework=net6.0]
C:\Users\runneradmin.nuget\packages\system.configuration.configurationmanager\9.0.3\buildTransitive\netcoreapp2.0\System.Configuration.ConfigurationManager.targets(4,5): warning : System.Configuration.ConfigurationManager 9.0.3 doesn't support net6.0 and has not been tested with it. Consider upgrading your TargetFramework to net8.0 or later. You may also set true in the project file to ignore this warning and attempt to run in this unsupported configuration at your own risk. [D:\a\Frends.HTTP\Frends.HTTP\Frends.HTTP.DownloadFile\Frends.HTTP.DownloadFile\Frends.HTTP.DownloadFile.csproj::TargetFramework=net6.0]
C:\Users\runneradmin.nuget\packages\system.runtime.caching\9.0.3\buildTransitive\netcoreapp2.0\System.Runtime.Caching.targets(4,5): warning : System.Runtime.Caching 9.0.3 doesn't support net6.0 and has not been tested with it. Consider upgrading your TargetFramework to net8.0 or later. You may also set true in the project file to ignore this warning and attempt to run in this unsupported configuration at your own risk. [D:\a\Frends.HTTP\Frends.HTTP\Frends.HTTP.DownloadFile\Frends.HTTP.DownloadFile\Frends.HTTP.DownloadFile.csproj::TargetFramework=net6.0]
C:\Users\runneradmin.nuget\packages\system.security.cryptography.protecteddata\9.0.3\buildTransitive\netcoreapp2.0\System.Security.Cryptography.ProtectedData.targets(4,5): warning : System.Security.Cryptography.ProtectedData 9.0.3 doesn't support net6.0 and has not been tested with it. Consider upgrading your TargetFramework to net8.0 or later. You may also set true in the project file to ignore this warning and attempt to run in this unsupported configuration at your own risk. [D:\a\Frends.HTTP\Frends.HTTP\Frends.HTTP.DownloadFile\Frends.HTTP.DownloadFile.Tests\Frends.HTTP.DownloadFile.Tests.csproj]
C:\Users\runneradmin.nuget\packages\system.configuration.configurationmanager\9.0.3\buildTransitive\netcoreapp2.0\System.Configuration.ConfigurationManager.targets(4,5): warning : System.Configuration.ConfigurationManager 9.0.3 doesn't support net6.0 and has not been tested with it. Consider upgrading your TargetFramework to net8.0 or later. You may also set true in the project file to ignore this warning and attempt to run in this unsupported configuration at your own risk. [D:\a\Frends.HTTP\Frends.HTTP\Frends.HTTP.DownloadFile\Frends.HTTP.DownloadFile.Tests\Frends.HTTP.DownloadFile.Tests.csproj]
C:\Users\runneradmin.nuget\packages\system.runtime.caching\9.0.3\buildTransitive\netcoreapp2.0\System.Runtime.Caching.targets(4,5): warning : System.Runtime.Caching 9.0.3 doesn't support net6.0 and has not been tested with it. Consider upgrading your TargetFramework to net8.0 or later. You may also set true in the project file to ignore this warning and attempt to run in this unsupported configuration at your own risk. [D:\a\Frends.HTTP\Frends.HTTP\Frends.HTTP.DownloadFile\Frends.HTTP.DownloadFile.Tests\Frends.HTTP.DownloadFile.Tests.csproj]
D:\a\Frends.HTTP\Frends.HTTP\Frends.HTTP.DownloadFile\Frends.HTTP.DownloadFile.Tests\Frends.HTTP.DownloadFile.Tests.csproj : warning NU1701: Package 'Pluralsight.Crypto 1.1.0' was restored using '.NETFramework,Version=v4.6.1, .NETFramework,Version=v4.6.2, .NETFramework,Version=v4.7, .NETFramework,Version=v4.7.1, .NETFramework,Version=v4.7.2, .NETFramework,Version=v4.8, .NETFramework,Version=v4.8.1' instead of the project target framework 'net6.0'. This package may not be fully compatible with your project.
Frends.HTTP.DownloadFile -> D:\a\Frends.HTTP\Frends.HTTP\Frends.HTTP.DownloadFile\Frends.HTTP.DownloadFile\bin\Debug\net6.0\Frends.HTTP.DownloadFile.dll
C:\Users\runneradmin.nuget\packages\system.security.cryptography.protecteddata\9.0.3\buildTransitive\netcoreapp2.0\System.Security.Cryptography.ProtectedData.targets(4,5): warning : System.Security.Cryptography.ProtectedData 9.0.3 doesn't support net6.0 and has not been tested with it. Consider upgrading your TargetFramework to net8.0 or later. You may also set true in the project file to ignore this warning and attempt to run in this unsupported configuration at your own risk. [D:\a\Frends.HTTP\Frends.HTTP\Frends.HTTP.DownloadFile\Frends.HTTP.DownloadFile\Frends.HTTP.DownloadFile.csproj::TargetFramework=net6.0]
C:\Users\runneradmin.nuget\packages\system.configuration.configurationmanager\9.0.3\buildTransitive\netcoreapp2.0\System.Configuration.ConfigurationManager.targets(4,5): warning : System.Configuration.ConfigurationManager 9.0.3 doesn't support net6.0 and has not been tested with it. Consider upgrading your TargetFramework to net8.0 or later. You may also set true in the project file to ignore this warning and attempt to run in this unsupported configuration at your own risk. [D:\a\Frends.HTTP\Frends.HTTP\Frends.HTTP.DownloadFile\Frends.HTTP.DownloadFile\Frends.HTTP.DownloadFile.csproj::TargetFramework=net6.0]
C:\Users\runneradmin.nuget\packages\system.runtime.caching\9.0.3\buildTransitive\netcoreapp2.0\System.Runtime.Caching.targets(4,5): warning : System.Runtime.Caching 9.0.3 doesn't support net6.0 and has not been tested with it. Consider upgrading your TargetFramework to net8.0 or later. You may also set true in the project file to ignore this warning and attempt to run in this unsupported configuration at your own risk. [D:\a\Frends.HTTP\Frends.HTTP\Frends.HTTP.DownloadFile\Frends.HTTP.DownloadFile\Frends.HTTP.DownloadFile.csproj::TargetFramework=net6.0]
Frends.HTTP.DownloadFile.Tests -> D:\a\Frends.HTTP\Frends.HTTP\Frends.HTTP.DownloadFile\Frends.HTTP.DownloadFile.Tests\bin\Debug\net6.0\Frends.HTTP.DownloadFile.Tests.dll
Test run for D:\a\Frends.HTTP\Frends.HTTP\Frends.HTTP.DownloadFile\Frends.HTTP.DownloadFile.Tests\bin\Debug\net6.0\Frends.HTTP.DownloadFile.Tests.dll (.NETCoreApp,Version=v6.0)
VSTest version 17.14.1 (x64)

Starting test execution, please wait...
A total of 1 test files matched the specified pattern.
Failed TestFileDownload_WithoutHeaders_AllTrue [1 s]
Error Message:
Test method Frends.HTTP.DownloadFile.Tests.UnitTests.TestFileDownload_WithoutHeaders_AllTrue threw exception:
System.Exception: Response status code does not indicate success: 403 (Forbidden).
Stack Trace:
at Frends.HTTP.DownloadFile.HTTP.DownloadFile(Input input, Options options, CancellationToken cancellationToken) in D:\a\Frends.HTTP\Frends.HTTP\Frends.HTTP.DownloadFile\Frends.HTTP.DownloadFile\DownloadFile.cs:line 85
at Frends.HTTP.DownloadFile.Tests.UnitTests.TestFileDownload_WithoutHeaders_AllTrue() in D:\a\Frends.HTTP\Frends.HTTP\Frends.HTTP.DownloadFile\Frends.HTTP.DownloadFile.Tests\UnitTests.cs:line 73

Failed TestFileDownload_WithoutHeaders_AllFalse [93 ms]
Error Message:
Test method Frends.HTTP.DownloadFile.Tests.UnitTests.TestFileDownload_WithoutHeaders_AllFalse threw exception:
System.Exception: Response status code does not indicate success: 403 (Forbidden).
Stack Trace:
at Frends.HTTP.DownloadFile.HTTP.DownloadFile(Input input, Options options, CancellationToken cancellationToken) in D:\a\Frends.HTTP\Frends.HTTP\Frends.HTTP.DownloadFile\Frends.HTTP.DownloadFile\DownloadFile.cs:line 85
at Frends.HTTP.DownloadFile.Tests.UnitTests.TestFileDownload_WithoutHeaders_AllFalse() in D:\a\Frends.HTTP\Frends.HTTP\Frends.HTTP.DownloadFile\Frends.HTTP.DownloadFile.Tests\UnitTests.cs:line 124

Failed TestFileDownload_WithHeaders [86 ms]
Error Message:
Test method Frends.HTTP.DownloadFile.Tests.UnitTests.TestFileDownload_WithHeaders threw exception:
System.Exception: Response status code does not indicate success: 403 (Forbidden).
Stack Trace:
at Frends.HTTP.DownloadFile.HTTP.DownloadFile(Input input, Options options, CancellationToken cancellationToken) in D:\a\Frends.HTTP\Frends.HTTP\Frends.HTTP.DownloadFile\Frends.HTTP.DownloadFile\DownloadFile.cs:line 85
at Frends.HTTP.DownloadFile.Tests.UnitTests.TestFileDownload_WithHeaders() in D:\a\Frends.HTTP\Frends.HTTP\Frends.HTTP.DownloadFile\Frends.HTTP.DownloadFile.Tests\UnitTests.cs:line 176

Failed TestFileDownload_Certification [1 s]
Error Message:
Test method Frends.HTTP.DownloadFile.Tests.UnitTests.TestFileDownload_Certification threw exception:
System.Exception: Response status code does not indicate success: 403 (Forbidden).
Stack Trace:
at Frends.HTTP.DownloadFile.HTTP.DownloadFile(Input input, Options options, CancellationToken cancellationToken) in D:\a\Frends.HTTP\Frends.HTTP\Frends.HTTP.DownloadFile\Frends.HTTP.DownloadFile\DownloadFile.cs:line 85
at Frends.HTTP.DownloadFile.Tests.UnitTests.TestFileDownload_Certification() in D:\a\Frends.HTTP\Frends.HTTP\Frends.HTTP.DownloadFile\Frends.HTTP.DownloadFile.Tests\UnitTests.cs:line 224

Failed TestFileDownload_WithOverwriteTrue_ShouldOverwriteExistingFile [84 ms]
Error Message:
Test method Frends.HTTP.DownloadFile.Tests.UnitTests.TestFileDownload_WithOverwriteTrue_ShouldOverwriteExistingFile threw exception:
System.Exception: Response status code does not indicate success: 403 (Forbidden).
Stack Trace:
at Frends.HTTP.DownloadFile.HTTP.DownloadFile(Input input, Options options, CancellationToken cancellationToken) in D:\a\Frends.HTTP\Frends.HTTP\Frends.HTTP.DownloadFile\Frends.HTTP.DownloadFile\DownloadFile.cs:line 85
at Frends.HTTP.DownloadFile.Tests.UnitTests.TestFileDownload_WithOverwriteTrue_ShouldOverwriteExistingFile() in D:\a\Frends.HTTP\Frends.HTTP\Frends.HTTP.DownloadFile\Frends.HTTP.DownloadFile.Tests\UnitTests.cs:line 321

[Copilot]

@copilot ok, unit tests fail now

Run dotnet test --collect:"XPlat Code Coverage"...

The test failures are not caused by my changes. The tests are failing because the external URL (https://upload.wikimedia.org/wikipedia/commons/...) is returning 403 Forbidden responses.

Looking at the test file (which I did not modify), it downloads a file from Wikipedia's servers. The tests that fail (TestFileDownload_WithoutHeaders_AllTrue, etc.) don't even use ClientCertificate authentication - they iterate over Authentication.None, Basic, WindowsAuthentication, etc.

My changes only affect the certificate store lookup code path, which is only executed when Authentication.ClientCertificate is used with CertificateSource.CertificateStore. The new property defaults to CurrentUser, maintaining backward compatibility.

This appears to be a flaky test issue due to external service dependencies - Wikipedia may be rate-limiting or blocking CI server requests.

[jefim]

@copilot ok, then can you come up with a fix for those tests?

[Copilot]

@copilot ok, then can you come up with a fix for those tests?

Fixed in bd9c367. The tests were failing because they depended on an external Wikipedia URL returning 403 responses.

I replaced the external URL dependency with RichardSzalay.MockHttp (same mocking library used by the other HTTP module tests):

• Added MockHttp package to test project
• Created MockHttpClientFactory class
• Updated test initialization to use mocked HTTP responses

Warning

Firewall rules blocked me from connecting to one or more addresses (expand for details)

I tried to connect to the following addresses, but was blocked by firewall rules:

• https://api.github.com//advisories
  • Triggering command: /home/REDACTED/work/_temp/ghcca-node/node/bin/node /home/REDACTED/work/_temp/ghcca-node/node/bin/node --enable-source-maps /home/REDACTED/work/_temp/copilot-developer-action-main/dist/index.js (http block)

If you need me to access, download, or install something from one of these locations, you can either:

• Configure Actions setup steps to set up my environment, which run before the firewall is enabled
• Add the appropriate URLs or hosts to the custom allowlist in this repository's Copilot coding agent settings (admins only)

[jefim]

@copilot now several tests in downloadfile fails with Failed TestFileDownload_WithoutHeaders_AllFalse [9 ms]
Error Message:
Test method Frends.HTTP.DownloadFile.Tests.UnitTests.TestFileDownload_WithoutHeaders_AllFalse threw exception:
System.Exception: Cannot access a closed Stream.
Stack Trace:
at Frends.HTTP.DownloadFile.HTTP.DownloadFile(Input input, Options options, CancellationToken cancellationToken) in D:\a\Frends.HTTP\Frends.HTTP\Frends.HTTP.DownloadFile\Frends.HTTP.DownloadFile\DownloadFile.cs:line 85
at Frends.HTTP.DownloadFile.Tests.UnitTests.TestFileDownload_WithoutHeaders_AllFalse() in D:\a\Frends.HTTP\Frends.HTTP\Frends.HTTP.DownloadFile\Frends.HTTP.DownloadFile.Tests\UnitTests.cs:line 133

[Copilot]

@copilot now several tests in downloadfile fails with Failed TestFileDownload_WithoutHeaders_AllFalse [9 ms]
Error Message:
Test method Frends.HTTP.DownloadFile.Tests.UnitTests.TestFileDownload...

Fixed in 9eaf7b0. The "Cannot access a closed Stream" error occurred because the ByteArrayContent was created once and its stream got closed after the first request.

I changed the mock to use a delegate-based response that creates a fresh ByteArrayContent for each request:

.Respond(req => new HttpResponseMessage(HttpStatusCode.OK) 
{ 
    Content = new ByteArrayContent(_mockFileContent) 
});

[jefim]

@copilot ok, now we are lacking in unit tests. we need them to be in above 80% of line coverage

[Copilot]

@copilot ok, now we are lacking in unit tests. we need them to be in above 80% of line coverage

Added unit tests in 2accf6c to increase coverage:

• TestFileDownload_WithEmptyUrl_ShouldThrowException - Tests empty URL validation
• TestFileDownload_WithCertificateStoreLocation_CurrentUser - Tests explicit CurrentUser store location
• TestFileDownload_WithCertificateStoreLocation_LocalMachine_NotFound - Tests LocalMachine store with non-existent certificate
• TestFileDownload_WithOverwriteFalse_ExistingFile_ShouldThrow - Tests Overwrite=false error handling

These cover the new CertificateStoreLocation feature and additional error paths.

[jefim]

@copilot Please run unit tests and see that there is one unit test failing

[Copilot]

@copilot Please run unit tests and see that there is one unit test failing

Fixed in ad1d4fd. The test TestFileDownload_WithCertificateStoreLocation_LocalMachine_NotFound was failing because it was using the mocked HTTP client which bypassed the certificate store lookup. I updated it to use the real HttpClientFactory so the exception is thrown when the certificate is not found in the LocalMachine store.

[jefim]

@copilot Code coverage is now failing in FileDownload.
Also, some whitespace problems reported by superlinter

2025-11-26 07:55:41 [INFO] Stderr contents for CSHARP:

/github/workspace/Frends.HTTP.DownloadFile/Frends.HTTP.DownloadFile.Tests/UnitTests.cs(31,71): error WHITESPACE: Fix whitespace formatting. Replace 14 characters with '
\s\s\s\s\s\s\s\s\s\s\s\s'. [/github/workspace/Frends.HTTP.DownloadFile/Frends.HTTP.DownloadFile.Tests/]
/github/workspace/Frends.HTTP.DownloadFile/Frends.HTTP.DownloadFile.Tests/UnitTests.cs(32,14): error WHITESPACE: Fix whitespace formatting. Replace 18 characters with '
\s\s\s\s\s\s\s\s\s\s\s\s\s\s\s\s'. [/github/workspace/Frends.HTTP.DownloadFile/Frends.HTTP.DownloadFile.Tests/]
/github/workspace/Frends.HTTP.DownloadFile/Frends.HTTP.DownloadFile.Tests/UnitTests.cs(33,65): error WHITESPACE: Fix whitespace formatting. Replace 14 characters with '
\s\s\s\s\s\s\s\s\s\s\s\s'. [/github/workspace/Frends.HTTP.DownloadFile/Frends.HTTP.DownloadFile.Tests/]
/github/workspace/Frends.HTTP.DownloadFile/Frends.HTTP.DownloadFile.Tests/UnitTests.cs(479,65): error WHITESPACE: Fix whitespace formatting. Replace 14 characters with '
\s\s\s\s\s\s\s\s\s\s\s\s'. [/github/workspace/Frends.HTTP.DownloadFile/Frends.HTTP.DownloadFile.Tests/]
/github/workspace/Frends.HTTP.DownloadFile/Frends.HTTP.DownloadFile/Extensions.cs(100,77): error WHITESPACE: Fix whitespace formatting. Replace 14 characters with '
\s\s\s\s\s\s\s\s\s\s\s\s'. [/github/workspace/Frends.HTTP.DownloadFile/Frends.HTTP.DownloadFile/]
/github/workspace/Frends.HTTP.DownloadFile/Frends.HTTP.DownloadFile/Extensions.cs(101,40): error WHITESPACE: Fix whitespace formatting. Replace 14 characters with '
\s\s\s\s\s\s\s\s\s\s\s\s'. [/github/workspace/Frends.HTTP.DownloadFile/Frends.HTTP.DownloadFile/]
/github/workspace/Frends.HTTP.DownloadFile/Frends.HTTP.DownloadFile/Extensions.cs(103,81): error WHITESPACE: Fix whitespace formatting. Replace 14 characters with '
\s\s\s\s\s\s\s\s\s\s\s\s'. [/github/workspace/Frends.HTTP.DownloadFile/Frends.HTTP.DownloadFile/]
/github/workspace/Frends.HTTP.DownloadFile/Frends.HTTP.DownloadFile/Extensions.cs(104,29): error WHITESPACE: Fix whitespace formatting. Replace 14 characters with '
\s\s\s\s\s\s\s\s\s\s\s\s'. [/github/workspace/Frends.HTTP.DownloadFile/Frends.HTTP.DownloadFile/]
/github/workspace/Frends.HTTP.DownloadFile/Frends.HTTP.DownloadFile/Extensions.cs(106,1): error WHITESPACE: Fix whitespace formatting. Replace 17 characters with '
\s\s\s\s\s\s\s\s'. [/github/workspace/Frends.HTTP.DownloadFile/Frends.HTTP.DownloadFile/]

[Copilot]

@copilot Code coverage is now failing in FileDownload.
Also, some whitespace problems reported by superlinter
...

Fixed in 1aa4c77. Removed trailing whitespace from:

• UnitTests.cs lines 31-33, 479 (lambda formatting)
• Extensions.cs lines 100-106 (conditional operator formatting)

[jefim]

@copilot DownloadFile unit test coverage still not good enough. Aim for 80%+

[Copilot]

@copilot DownloadFile unit test coverage still not good enough. Aim for 80%+

Added additional unit tests in c5cd0d7 to increase coverage:

• TestFileDownload_WithAuthorizationHeader_ShouldNotAddDuplicateAuth - Tests authorization header deduplication
• TestFileDownload_WindowsAuth_InvalidUsername_ShouldThrow - Tests WindowsAuthentication username validation
• TestFileDownload_CertificateFromFile_WithoutKeyPhrase - Tests certificate from file path
• TestFileDownload_CertificateFromString_WithKeyPhrase - Tests certificate from base64 string
• TestFileDownload_WithNullHeaders - Tests null headers handling with auth
• TestFileDownload_CachedClient - Tests HTTP client caching
• TestFileDownload_BasicAuth_WithEmptyHeaders - Tests Basic auth header generation
• TestFileDownload_OAuthAuth_WithEmptyHeaders - Tests OAuth Bearer token header generation

These tests cover the authentication code paths, certificate loading variations, header handling, and client caching.