It won't happen very often but occasionally you will be faced with an unexpected psychological, aptitude, vocational, or technical test or exam. There is little you can do to prepare for these tests, but you can do your best if you just relax and answer honestly. Second guessing and distorting answers will only get you in trouble.
If the test is worth anything at all, it will be able to discriminate between those who are honest or really know what they are doing and those who are lying or trying to please the employer at the expense of reality.
If you feel particularly vulnerable or inadequate at that moment, you can always ask to take the test at another time. You might indicate that you are scheduled to be somewhere else in an hour, or that you don't think that you will do your best at this particular time. You can also simply refuse to take the test on the basis that you did not expect that this would be a condition of employment.
The best advice is not to put it off because refusal or reluctance to take the test may automatically disqualify you.
The immediate offer
From time to time, an overly enthusiastic employer may offer you the job on the spot. It may be very tempting to accept such an offer immediately, but that would probably be a mistake in most instances.
Anybody that anxious to offer you a job should clearly be held suspect. You should ask yourself just why he is or she is so anxious. Is it because no one else wants it? Or maybe he or she hasn't told you the complete story and doesn't want you to find out the truth before you accept. Or perhaps the interviewer is untrained and inexperienced. In such situations, it is not unusual for the employer to jump the gun and offer the job to the first acceptable candidate who comes along. From his or her point of view, it may be a quick solution to a difficult problem. No matter what the reason for the employer's behavior, to accept the offer without due consideration is generally a mistake and both parties lose.
The candidate loses in that he or she may accept a job that he or she really doesn't want because of a momentary enthusiasm that can easily overshadow the realities of the situation.
The employer loses because studies show that the rate of turnover with immediate hires is substantially greater than normal. Employees either get fired because they can't do the job expected of them, or they quit because they are disappointed with the job. And when you consider that it costs thousands of dollars to hire and train a single new employee, the employer's loss is significant.
New and unacceptable conditions
Sometime in your job search you may encounter a situation similar to this: you are offered a job over the phone a few days after the interview has taken place. You accept the offer but when you show up to start work you are told that: (1) the job pays less than they originally told you; (2) you must work overtime on a routine basis; (3) the first week is training and you won't be paid for it; or (4) they have decided that they need you in a different department doing work that you hate, etc.. Such occurrences are not at all unusual. In the retail business this is known as "Switch and Bait" (advertising one thing and when the customer shows up, selling him or her something else).
As a rule, employer strategies of this sort are very deliberate and designed to intimidate you. The employer knows that you have either quit your old job or that you have set your mind on working for his or her company. Rather than having no job at all or losing this opportunity to work for the company, you will probably feel compelled to accept the new conditions. There are times when this will seem to be the only thing you can do. But bear in mind that this is a very poor way to begin a new job and the chances are very high that it won't work out. If you do accept the job, the best advice I can give, is to put the matter behind you.