User-821857111 posted
Looks like you might have copied the pattern from a JS regex example. You don't need the escape characters:
var inputs = new[]{"test","test new","new test","testtt"};
foreach(var input in inputs)
{
Console.WriteLine(Regex.IsMatch(input, @"\b(test)\b"));
}
Note also that your example tests the string "input", which will always result in false.
