This depends on the type of vacancy you apply for. Testing is a standard part of the selection procedure for the following two areas:
Software development
After the first interview, Software Engineers will be asked to complete a Java Development Test. The test will be emailed to you and you will have a specified time period in which to complete it.
Trading
For Graduate Traders, tests are part of the application procedure. You should expect
aptitude tests including numerical and inductive reasoning, mental calculation tests and personality profile tests.