From 49ad041b87a24636d8cc1f1bae78e142fc4b56c3 Mon Sep 17 00:00:00 2001
From: "Darrin W. Cullop" <Darrin.Cullop@microsoft.com>
Date: Sun, 17 Dec 2023 21:08:08 -0800
Subject: [PATCH] Fix ObservableSpy null mismatch issues (#803)

---
 src/DynamicData.Tests/Utilities/ObservableSpy.cs | 6 +++---
 1 file changed, 3 insertions(+), 3 deletions(-)

diff --git a/src/DynamicData.Tests/Utilities/ObservableSpy.cs b/src/DynamicData.Tests/Utilities/ObservableSpy.cs
index 20cb3515e..2cb95ff23 100644
--- a/src/DynamicData.Tests/Utilities/ObservableSpy.cs
+++ b/src/DynamicData.Tests/Utilities/ObservableSpy.cs
@@ -127,7 +127,7 @@ private static Func<IChangeSet<T>, string> CreateListChangeSetFormatter<T>(Func<
         cs => "[List Change Set]" + ChangeSetEntrySpacing + string.Join(ChangeSetEntrySpacing, cs.Select((change, n) => $"#{n} {FormatChange(formatter, change)}"));
 
     public static IObservable<T> DebugSpy<T>(this IObservable<T> source, string? opName = null,
-                                                                  Func<T, string?>? formatter = null, bool showSubs = true,
+                                                                  Func<T, string>? formatter = null, bool showSubs = true,
                                                                   bool showTimestamps = true) =>
 #if DEBUG || DEBUG_SPY_ALWAYS
         source.Spy(opName, DebugLogger, formatter, showSubs, showTimestamps);
@@ -137,7 +137,7 @@ public static IObservable<T> DebugSpy<T>(this IObservable<T> source, string? opN
 
     public static IObservable<IChangeSet<T, TKey>> DebugSpy<T, TKey>(this IObservable<IChangeSet<T, TKey>> source,
                                                                     string? opName = null,
-                                                                    Func<T, string?>? formatter = null, bool showSubs = true,
+                                                                    Func<T, string>? formatter = null, bool showSubs = true,
                                                                       bool showTimestamps = true)
         where T : notnull
         where TKey : notnull =>
@@ -149,7 +149,7 @@ public static IObservable<IChangeSet<T, TKey>> DebugSpy<T, TKey>(this IObservabl
 
     public static IObservable<IChangeSet<T>> DebugSpy<T>(this IObservable<IChangeSet<T>> source,
                                                                     string? opName = null,
-                                                                    Func<T, string?>? formatter = null, bool showSubs = true,
+                                                                    Func<T, string>? formatter = null, bool showSubs = true,
                                                                       bool showTimestamps = true)
                                                                       where T : notnull =>
 #if DEBUG || DEBUG_SPY_ALWAYS