The scope of pre-employment medical examinations varies between different types of occupation. (Deep-sea divers, for example, probably need to be a good deal fitter than an office worker). Some employers require exceptionally high standards. Others only require you to prove that you're not actually dead!
The last time I had a pre-employment medical, it was for a job in the rail industry. I had to fill in a detailed questionnaire about whether I'd ever suffered from any of a long list of diseases. Then there was a fairly standard examination by the doctor and his nursing team. This included measurement of my height and weight, listening to my heart and chest, a check on my pulse rates (before, during and after brief exercise), and a blood pressure reading. My eyesight was also assessed (both with and without my glasses) and my colour vision was checked. Additionally, there was a fairly lengthy electronic testing session for my hearing. A urine sample was taken and this was tested for the presence of sugar (which might indicate diabetes), alcohol and illegal drugs. (Unusually, for such an extensive medical, no blood sample was taken). The efficiency of my lungs was tested by blowing into a device which measured the pressure exerted by exhalation.
Also, being a fella, there was the old 'drop and cough' hernia test. (The doctor holds your balls in the palm of his hand and asks you to cough).
The whole thing took about 90 minutes.
That medical was carried out at a clinic which specialises in assessing the health of workers on North Sea oil rigs, so their tests may well have been more detailed than the one which you'll have.
Chris