How to write unit test for ActionFilter when using Service Locator
<p>I am planning to write an <code>ActionFilter</code> for business validation and in which some services will be resolved via Service Locator(I know this is not good practice and as far as possible i avoid Service Locator pattern, but for this case i want to use it). </p>

<p><code>OnActionExecuting</code> method of the filter is something like this:</p>

<pre><code>    public override void OnActionExecuting(ActionExecutingContext actionContext)
    {
        // get validator for input;
        var validator = actionContext.HttpContext.RequestServices.GetService&lt;IValidator&lt;TypeOfInput&gt;&gt;();// i will ask another question for this line
        if(!validator.IsValid(input))
        {
            //send errors
        }
    }
</code></pre>

<p>Is it possible to write unit test for above <code>ActionFilter</code>and how?</p>