Add unit tests for EstateRequestHandler to achieve full coverage

[Copilot]

EstateRequestHandler had no unit test coverage across its four MediatR handler methods.

Changes

• New file: EstateManagementUI.BlazorServer.Tests/RequestHandlers/EstateRequestHandlerTests.cs
  • 8 tests covering all 4 handler methods × (success + failure) paths:
    • GetEstateQuery → ApiClient.GetEstate
    • AddOperatorToEstateCommand → ApiClient.AddEstateOperator
    • RemoveOperatorFromEstateCommand → ApiClient.RemoveEstateOperator
    • GetAssignedOperatorsQuery → ApiClient.GetEstateAssignedOperators
  • Each test verifies IsSuccess/IsFailed on the returned Result and asserts the API client was called exactly once via Moq.Verify

[Fact]
public async Task Handle_GetEstateQuery_ReturnsSuccess_WhenApiClientSucceeds()
{
    var query = new EstateQueries.GetEstateQuery(CorrelationIdHelper.New(), estateId);
    _mockApiClient.Setup(c => c.GetEstate(query, It.IsAny<CancellationToken>()))
                  .ReturnsAsync(Result.Success(estateModel));

    var result = await _handler.Handle(query, CancellationToken.None);

    result.IsSuccess.ShouldBeTrue();
    _mockApiClient.Verify(c => c.GetEstate(query, It.IsAny<CancellationToken>()), Times.Once);
}

Follows the same conventions as the existing DateRequestHandlerTests.

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:

• f.feedz.io
  • Triggering command: /usr/bin/dotnet dotnet test EstateManagementUI.BlazorServer.Tests/EstateManagementUI.BlazorServer.Tests.csproj --filter FullyQualifiedName~EstateRequestHandlerTests (dns block)
  • Triggering command: /opt/hostedtoolcache/CodeQL/2.24.0/x64/codeql/csharp/tools/linux64/Semmle.Autobuild.CSharp /opt/hostedtoolcache/CodeQL/2.24.0/x64/codeql/csharp/tools/linux64/Semmle.Autobuild.CSharp (dns block)
  • Triggering command: /usr/bin/dotnet dotnet restore --no-dependencies /home/REDACTED/work/EstateManagementUI/EstateManagementUI/EstateManagementUI.sln --packages /home/REDACTED/work/EstateManagementUI/.codeql-scratch/dbs/csharp/working/packages /p:DisableImplicitNuGetFallbackFolder=true --verbosity normal /p:TargetFrameworkRootPath=/home/REDACTED/work/EstateManagementUI/.codeql-scratch/dbs/csharp/working/emptyFakeDotnetRoot /p:NetCoreTargetingPackRoot=/home/REDACTED/work/EstateManagementUI/.codeql-scratch/dbs/csharp/working/emptyFakeDotnetRoot /p:AllowMissingPrunePackageData=true (dns 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)

Original prompt

---

This section details on the original issue you should resolve

<issue_title>EstateRequestHandler Unit Tests</issue_title>
<issue_description>Ensure a good level of code coverage as close to 100% as possible</issue_description>

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

• Fixes EstateRequestHandler Unit Tests #782

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