Implement SubtractSaturating method for TimeSpan with comprehensive tests

Co-authored-by: niemyjski <[email protected]>

Author: Copilot

src/Exceptionless.DateTimeExtensions/TimeSpanExtensions.cs

@@ -88,6 +88,11 @@ public static AgeSpan ToAgeSpan(this TimeSpan span)
     {
         return new AgeSpan(span);
     }
+
+    public static TimeSpan SubtractSaturating(this TimeSpan self, TimeSpan other)
+    {
+        return self >= other ? self.Subtract(other) : TimeSpan.Zero;
+    }
 }
 
 public struct AgeSpan

tests/Exceptionless.DateTimeExtensions.Tests/TimeSpanExtensionTests.cs

@@ -65,4 +65,43 @@ public void ApproximateAge()
         Assert.Equal("2 days ago", DateTime.Now.AddHours(-48).ToApproximateAgeString());
         Assert.Equal("1 week ago", DateTime.Now.AddDays(-7).ToApproximateAgeString());
     }
+
+    [Fact]
+    public void SubtractSaturating()
+    {
+        // Basic case: normal subtraction when result is positive
+        var timeSpan1 = TimeSpan.FromHours(5);
+        var timeSpan2 = TimeSpan.FromHours(2);
+        Assert.Equal(TimeSpan.FromHours(3), timeSpan1.SubtractSaturating(timeSpan2));
+
+        // Saturating case: result would be negative, should return TimeSpan.Zero
+        var timeSpan3 = TimeSpan.FromHours(2);
+        var timeSpan4 = TimeSpan.FromHours(5);
+        Assert.Equal(TimeSpan.Zero, timeSpan3.SubtractSaturating(timeSpan4));
+
+        // Edge case: equal values should return TimeSpan.Zero
+        var timeSpan5 = TimeSpan.FromMinutes(30);
+        var timeSpan6 = TimeSpan.FromMinutes(30);
+        Assert.Equal(TimeSpan.Zero, timeSpan5.SubtractSaturating(timeSpan6));
+
+        // Zero cases
+        Assert.Equal(TimeSpan.FromSeconds(10), TimeSpan.FromSeconds(10).SubtractSaturating(TimeSpan.Zero));
+        Assert.Equal(TimeSpan.Zero, TimeSpan.Zero.SubtractSaturating(TimeSpan.FromSeconds(5)));
+        Assert.Equal(TimeSpan.Zero, TimeSpan.Zero.SubtractSaturating(TimeSpan.Zero));
+
+        // Large values
+        var largeTimeSpan1 = TimeSpan.FromDays(100);
+        var largeTimeSpan2 = TimeSpan.FromDays(50);
+        Assert.Equal(TimeSpan.FromDays(50), largeTimeSpan1.SubtractSaturating(largeTimeSpan2));
+
+        // Negative TimeSpan values - testing with negative self value
+        var negativeTimeSpan = TimeSpan.FromHours(-2);
+        var positiveTimeSpan = TimeSpan.FromHours(1);
+        Assert.Equal(TimeSpan.Zero, negativeTimeSpan.SubtractSaturating(positiveTimeSpan));
+
+        // Negative other value (subtracting negative is like adding)
+        var timeSpan7 = TimeSpan.FromHours(3);
+        var negativeTimeSpan2 = TimeSpan.FromHours(-2);
+        Assert.Equal(TimeSpan.FromHours(5), timeSpan7.SubtractSaturating(negativeTimeSpan2));
+    }
 }