Stop todo evaluation at given datetime

Ical.Net.Tests/TodoTest.cs

@@ -3,7 +3,6 @@
 // Licensed under the MIT license.
 //
 
-using System;
 using System.Collections;
 using System.Collections.Generic;
 using System.Linq;
@@ -240,4 +239,30 @@ public void Todo_WithFutureStart_AndNoDuration_ShouldSucceed()
         Assert.That(firstOccurrence.Period.StartTime, Is.Not.Null);
         Assert.That(firstOccurrence.Period.Duration, Is.Null);
     }
+
+    [Test, Category("Todo")]
+    public void Todo_RecurrenceWithNoEnd_IsCompletedUntilNextOccurrence()
+    {
+        var start = new CalDateTime(2026, 1, 15, 0, 0, 0, "UTC");
+
+        var todo = new Todo
+        {
+            Start = start,
+            RecurrenceRules = [new("FREQ=DAILY;BYDAY=TH")],
+        };
+
+        todo.Status = "COMPLETED";
+        todo.Completed = new CalDateTime(2026, 1, 16, 0, 0, 0, "UTC");
+
+        var results = Enumerable.Range(14, 10)
+            .Select(x => new CalDateTime(2026, 1, x, 0, 0, 0, "UTC"))
+            .Select(todo.IsCompleted)
+            .ToList();
+
+        // Jan 14-21: true (8 days) - TODO is considered completed
+        // Jan 22-23: false (2 days) - TODO is NOT completed
+        List<bool> expected = [true, true, true, true, true, true, true, true, false, false];
+
+        Assert.That(results, Is.EquivalentTo(expected));
+    }
 }

Ical.Net/Evaluation/TodoEvaluator.cs

@@ -35,7 +35,7 @@
         DetermineStartingRecurrence(Todo.RecurrenceDates.GetAllPeriods(), ref beginningDate);
         DetermineStartingRecurrence(Todo.RecurrenceDates.GetAllDates(), ref beginningDate);
 
         foreach (var exrule in Todo.ExceptionRules)
         {
             DetermineStartingRecurrence(exrule, ref beginningDate);
         }
@@ -48,7 +48,7 @@
         }
 
         return Evaluate(Todo.Start, beginningDate, options)
-            .Where(p => p.StartTime <= currDt);
+            .TakeWhile(p => p.StartTime <= currDt);
     }
 
     private static void DetermineStartingRecurrence(IEnumerable<Period> rdate, ref CalDateTime referenceDateTime)