Thursday part 2: Improve SampleStage

[olliesilvester]

Add the following functionality to the SampleStage device

• A set function, which accepts two parameters, the desired position for each motor:

• The function checks to see if the parameters are within the limits of the motor, and throws a custom exception if they are not

• Each motor checks the position it is currently at, and then checks its current velocity to see how long it will take to do the move.

• Both motors should move to their positions at the same time, and throw a timeout error if it took longer than the time calculated above

• Create a new class attribute called 'previous_positions', which is a list which updates every time the 'set' function is called, and keeps track of all the positions we moved to

• Also create a 'read' function which returns the current value of motor x and the rotation motor. This should be in a dictionary format. Eg {'x': 0, 'A': 120}

Write tests for these as thoroughly as you can!