Robot Name

Instructions

Manage robot factory settings.

When a robot comes off the factory floor, it has no name.

The first time you turn on a robot, a random name is generated in the format of two uppercase letters followed by three digits, such as RX837 or BC811.

Every once in a while we need to reset a robot to its factory settings, which means that its name gets wiped. The next time you ask, that robot will respond with a new random name.

The names must be random: they should not follow a predictable sequence. Using random names means a risk of collisions. Your solution must ensure that every existing robot has a unique name.

It is possible to run out of robot names - once every possible robot name has been allocated then an error should be returned.

Bonus test

Once you get go test passing, you will find that there is a test in the test suite named TestCollisions which is skipped by default since it can take a long time. This test creates new robots until no more new names can be assigned to the robot.

To get the test to run, remove this line:

t.Skip("skipping test as it can take a long time to run if solution is sub-optimal.")

To get this test to pass you'll have to ensure a robot's name has not been used before and that names can be allocated efficiently.