Joseph Doherty
c9244d8bda
AddSiteEventLogHealthMetricsBridge registered via AddHostedService(factory-lambda), which sets ImplementationFactory and leaves ImplementationType null. The prior ImplementationType == guard was therefore silently dead — a second call would spin up a second SiteEventLogFailureCountReporter. Fix: add a private SiteEventLogHealthMetricsBridgeMarker singleton and guard on its ServiceType instead. Also corrects the cycle-path comment in both ServiceCollectionExtensions.cs and SiteEventLogFailureCountReporter.cs: StoreAndForward.csproj does reference SiteEventLogging.csproj, so the transitive path HealthMonitoring → StoreAndForward → SiteEventLogging is real, but adding a direct HealthMonitoring → SiteEventLogging reference would NOT create a cycle (SiteEventLogging has no back-edge to HealthMonitoring). The Func<long> seam is a coupling-avoidance measure, not a cycle-breaker. Adds AddSiteEventLogHealthMetricsBridgeTests.AddSiteEventLogHealthMetricsBridge_IsIdempotent_DoesNotDoubleRegister_HostedService as a regression test (builds provider and asserts exactly one reporter via GetServices<IHostedService>().OfType<T>()).
49 lines
2.2 KiB
C#
49 lines
2.2 KiB
C#
using Microsoft.Extensions.DependencyInjection;
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using Microsoft.Extensions.Hosting;
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using Microsoft.Extensions.Logging;
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using Microsoft.Extensions.Logging.Abstractions;
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namespace ZB.MOM.WW.ScadaBridge.HealthMonitoring.Tests;
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/// <summary>
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/// M2.16 (#30) idempotency regression — code-review finding on commit d81f747.
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/// <para>
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/// <see cref="ServiceCollectionExtensions.AddSiteEventLogHealthMetricsBridge"/> uses a
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/// factory-lambda overload of <c>AddHostedService</c>, which sets only
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/// <c>ImplementationFactory</c> and leaves <c>ImplementationType</c> null. The original
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/// <c>ImplementationType ==</c> guard was therefore a silent no-op: a second call would spin
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/// up a second <see cref="SiteEventLogFailureCountReporter"/> (two timers both polling).
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/// The fix uses a private marker singleton whose <c>ServiceType</c> is always set.
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/// </para>
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/// </summary>
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public class AddSiteEventLogHealthMetricsBridgeTests
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{
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[Fact]
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public void AddSiteEventLogHealthMetricsBridge_IsIdempotent_DoesNotDoubleRegister_HostedService()
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{
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// M2.16 (#30): calling the bridge method twice must register exactly one
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// SiteEventLogFailureCountReporter. Without the marker-type guard the
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// ImplementationType == check was a no-op for factory-lambda registrations,
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// so the second call would have added a second hosted service (two timers).
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var services = new ServiceCollection();
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services.AddSingleton<ILoggerFactory, NullLoggerFactory>();
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services.AddSingleton(typeof(ILogger<>), typeof(NullLogger<>));
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services.AddHealthMonitoring();
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Func<IServiceProvider, Func<long>> factory = _ => () => 0L;
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services.AddSiteEventLogHealthMetricsBridge(factory);
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services.AddSiteEventLogHealthMetricsBridge(factory);
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// Count IHostedService descriptors whose factory produces a
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// SiteEventLogFailureCountReporter. Because it is factory-registered,
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// ImplementationType is null — we count by resolving and checking type.
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using var provider = services.BuildServiceProvider();
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var reporters = provider.GetServices<IHostedService>()
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.OfType<SiteEventLogFailureCountReporter>()
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.ToList();
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Assert.Single(reporters);
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}
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}
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