Whenever we need to evaluate someone, we try to conduct a test and his score gives us an initial impression about him. Same is the case with recruitment, in most organizations, recruitment starts with a test to shortlist candidates for interviewing and further interviewing. This is not possible without a test because no organization can do bulk interview in hope of finding the best candidate. When you shortlist the candidates based on the scores of sales test you are in a better position to tell which candidate would be better for your organization. Hiring sale reps must be a quick process because an entity cannot delay in hiring the sales team which is going to generate sales. If you are in a constant need to hire sale rep, you must devise a test that best suits your requirements and should use that test to ensure the hiring of best candidate whenever a job opening is found.
In order to get the best results, it is highly advised that you use the expertise of professionals around you who are expert in making such aptitude tests. Normally HR firms and sales experts are hired for this purpose. Sales experts together with HR personnel can devise a test that would fulfil all your needs because they exactly know what is required in a sales rep and how can they assess it. If you have sales expert in your organization, you can collaborate these two departments to get the best hiring otherwise the best way out is to outsource this task as there are many professionals who would take the pain to find the most suited candidate for your organization without any problem.
The nature of your business would decide the quantity and quality of sales staff needed. If you are selling a socialized product to a particular market, then you must need highly proficient staff who knows the technical details of the product precisely. For this purpose, you can arrange trainings and workshops for your sales staff once hired, but before hiring try to focus more on the skills and past experience.