diff --git a/src/NUnitFramework/tests/TestUtilities/TestAssert.cs b/src/NUnitFramework/tests/TestUtilities/TestAssert.cs
index e9ff5cf447..59b7bbb216 100644
--- a/src/NUnitFramework/tests/TestUtilities/TestAssert.cs
+++ b/src/NUnitFramework/tests/TestUtilities/TestAssert.cs
@@ -36,7 +36,7 @@ public static void IsRunnable(Type type, string name, ResultState resultState)
             object testObject = Reflect.Construct(type);
             ITestResult result = TestBuilder.RunTest(test, testObject);
             if (result.HasChildren) // In case it's a parameterized method
-                result = result.Children.ToArray()[0];
+                result = result.Children.First();
             Assert.That(result.ResultState, Is.EqualTo(resultState));
         }
         #endregion