Error with ObservableLoggingOverrideMixin

[jibedoubleve]

[xUnit.net 00:00:43.80]     Lanceur.Tests.ViewModels.KeywordViewModelShould.NotBeAbleToSaveEmptySynonyms(synonyms: "un  , deux , trois", synonymCount: 3) [FAIL]
[xUnit.net 00:00:43.92]     Lanceur.Tests.ViewModels.MainViewModelShould.ExecuteSelectedAliasWhenGoToNext [FAIL]
[xUnit.net 00:00:43.94]     Lanceur.Tests.ViewModels.AllViewModelsShould.InstantiateWithoutError(vmType: typeof(Lanceur.Views.MainViewModel)) [FAIL]
  Failed Lanceur.Tests.ViewModels.KeywordViewModelShould.NotBeAbleToSaveEmptySynonyms(synonyms: "un  , deux , trois", synonymCount: 3) [3 s]
  Error Message:
   System.TypeInitializationException : The type initializer for 'Lanceur.Utils.ObservableLoggingOverrideMixin' threw an exception.
---- System.NullReferenceException : Object reference not set to an instance of an object.
  Stack Trace:
     at Lanceur.Utils.ObservableLoggingOverrideMixin.WriteLog(LogLevel logLevel, String message, Object[] arguments) in D:\a\lanceur-bis\lanceur-bis\src\Lanceur\Utils\ObservableLoggingOverrideMixin.cs:line 26
   at Lanceur.Utils.ObservableLoggingOverrideMixin.<>c__DisplayClass2_0`1.<WriteLog>b__0(T x) in D:\a\lanceur-bis\lanceur-bis\src\Lanceur\Utils\ObservableLoggingOverrideMixin.cs:line 74
   at System.Reactive.Linq.ObservableImpl.Do`1.Actions._.OnNext(TSource value) in /_/Rx.NET/Source/src/System.Reactive/Linq/Observable/Do.cs:line 158
--- End of stack trace from previous location ---
   at System.Reactive.PlatformServices.ExceptionServicesImpl.Rethrow(Exception exception) in /_/Rx.NET/Source/src/System.Reactive/Internal/ExceptionServicesImpl.cs:line 19
   at System.Reactive.ExceptionHelpers.Throw(Exception exception) in /_/Rx.NET/Source/src/System.Reactive/Internal/ExceptionServices.cs:line 16
   at System.Reactive.Stubs.<>c.<.cctor>b__2_1(Exception ex) in /_/Rx.NET/Source/src/System.Reactive/Internal/Stubs.cs:line 16
   at System.Reactive.AnonymousSafeObserver`1.OnError(Exception error) in /_/Rx.NET/Source/src/System.Reactive/AnonymousSafeObserver.cs:line 62
   at System.Reactive.Sink`1.ForwardOnError(Exception error) in /_/Rx.NET/Source/src/System.Reactive/Internal/Sink.cs:line 60
   at System.Reactive.Linq.ObservableImpl.SelectMany`2.ObservableSelector._.OnError(Exception error) in /_/Rx.NET/Source/src/System.Reactive/Linq/Observable/SelectMany.cs:line 887
   at System.Reactive.Sink`1.ForwardOnError(Exception error) in /_/Rx.NET/Source/src/System.Reactive/Internal/Sink.cs:line 60
   at System.Reactive.Sink`2.OnError(Exception error) in /_/Rx.NET/Source/src/System.Reactive/Internal/Sink.cs:line 94
   at System.Reactive.Sink`1.ForwardOnError(Exception error) in /_/Rx.NET/Source/src/System.Reactive/Internal/Sink.cs:line 60
   at System.Reactive.Sink`2.OnError(Exception error) in /_/Rx.NET/Source/src/System.Reactive/Internal/Sink.cs:line 94
   at System.Reactive.Sink`1.ForwardOnError(Exception error) in /_/Rx.NET/Source/src/System.Reactive/Internal/Sink.cs:line 60
   at System.Reactive.Linq.ObservableImpl.Switch`1._.InnerObserver.OnError(Exception error) in /_/Rx.NET/Source/src/System.Reactive/Linq/Observable/Switch.cs:line 114
   at System.Reactive.Sink`1.ForwardOnError(Exception error) in /_/Rx.NET/Source/src/System.Reactive/Internal/Sink.cs:line 60
   at System.Reactive.Sink`2.OnError(Exception error) in /_/Rx.NET/Source/src/System.Reactive/Internal/Sink.cs:line 94
   at System.Reactive.Subjects.Subject`1.OnError(Exception error) in /_/Rx.NET/Source/src/System.Reactive/Subjects/Subject.cs:line 120
   at System.Reactive.Sink`1.ForwardOnError(Exception error) in /_/Rx.NET/Source/src/System.Reactive/Internal/Sink.cs:line 60
   at System.Reactive.Sink`2.OnError(Exception error) in /_/Rx.NET/Source/src/System.Reactive/Internal/Sink.cs:line 94
   at System.Reactive.Sink`1.ForwardOnError(Exception error) in /_/Rx.NET/Source/src/System.Reactive/Internal/Sink.cs:line 60
   at System.Reactive.Linq.ObservableImpl.Do`1.Actions._.OnNext(TSource value) in /_/Rx.NET/Source/src/System.Reactive/Linq/Observable/Do.cs:line 162
   at System.Reactive.Sink`1.ForwardOnNext(TTarget value) in /_/Rx.NET/Source/src/System.Reactive/Internal/Sink.cs:line 49
   at System.Reactive.Linq.ObservableImpl.Select`2.Selector._.OnNext(TSource value) in /_/Rx.NET/Source/src/System.Reactive/Linq/Observable/Select.cs:line 47
   at System.Reactive.Sink`1.ForwardOnNext(TTarget value) in /_/Rx.NET/Source/src/System.Reactive/Internal/Sink.cs:line 49
   at System.Reactive.Linq.ObservableImpl.Throttle`1._.Propagate(UInt64 currentid) in /_/Rx.NET/Source/src/System.Reactive/Linq/Observable/Throttle.cs:line 77
   at System.Reactive.Linq.ObservableImpl.Throttle`1._.<>c.<OnNext>b__9_0(ValueTuple`2 tuple) in /_/Rx.NET/Source/src/System.Reactive/Linq/Observable/Throttle.cs:line 68
   at System.Reactive.Concurrency.Scheduler.Invoke[TState](ValueTuple`2 tuple) in /_/Rx.NET/Source/src/System.Reactive/Concurrency/Scheduler.Simple.cs:line 259
   at System.Reactive.Concurrency.Scheduler.<>c__78`1.<ScheduleAction>b__78_0(IScheduler _, ValueTuple`2 tuple) in /_/Rx.NET/Source/src/System.Reactive/Concurrency/Scheduler.Simple.cs:line 137
   at System.Reactive.Concurrency.VirtualTimeScheduler`2.<>c__DisplayClass4_0`1.<ScheduleAbsolute>b__0(IScheduler scheduler, TState state1) in /_/Rx.NET/Source/src/System.Reactive/Concurrency/VirtualTimeScheduler.cs:line 439
   at System.Reactive.Concurrency.ScheduledItem`2.InvokeCore() in /_/Rx.NET/Source/src/System.Reactive/Concurrency/ScheduledItem.cs:line 205
   at System.Reactive.Concurrency.ScheduledItem`1.Invoke() in /_/Rx.NET/Source/src/System.Reactive/Concurrency/ScheduledItem.cs:line 44
   at System.Reactive.Concurrency.VirtualTimeSchedulerBase`2.Start() in /_/Rx.NET/Source/src/System.Reactive/Concurrency/VirtualTimeScheduler.cs:line 179
   at Lanceur.Tests.ViewModels.KeywordViewModelShould.<>c__DisplayClass5_0.<NotBeAbleToSaveEmptySynonyms>b__0(TestScheduler scheduler) in D:\a\lanceur-bis\lanceur-bis\src\Tests\Lanceur.Tests\ViewModels\KeywordViewModelShould.cs:line 222
   at ReactiveUI.Testing.SchedulerExtensions.<>c__DisplayClass4_0`1.<With>b__0(T x) in /_/src/ReactiveUI.Testing/SchedulerExtensions.cs:line 116
   at ReactiveUI.Testing.SchedulerExtensions.With[T,TRet](T scheduler, Func`2 block) in /_/src/ReactiveUI.Testing/SchedulerExtensions.cs:line 71
   at ReactiveUI.Testing.SchedulerExtensions.With[T](T scheduler, Action`1 block) in /_/src/ReactiveUI.Testing/SchedulerExtensions.cs:line 114
   at Lanceur.Tests.ViewModels.KeywordViewModelShould.NotBeAbleToSaveEmptySynonyms(String synonyms, Int32 synonymCount) in D:\a\lanceur-bis\lanceur-bis\src\Tests\Lanceur.Tests\ViewModels\KeywordViewModelShould.cs:line 197
----- Inner Stack Trace -----
   at Lanceur.Utils.ObservableLoggingOverrideMixin..cctor() in D:\a\lanceur-bis\lanceur-bis\src\Lanceur\Utils\ObservableLoggingOverrideMixin.cs:line 15