Based on your diagram, looks like you're switching the neutral? This is super dangerous - switches should be on the hot wires and not on the neutral (otherwise the bulb socket is still receiving power even if the switch is off).
The light should be wired directly to the neutral, and then run your hot wire through the switch back to the light.
Nick is right here. Are you sure you have all the wires depicted correctly?
(In this case, I am assuming you meant to call the big yellow thing the fan/light AND you have depicted ALL the wires going from the light to the light box and then to the switches.)
It seems what you are showing is switched neutral as Nick says that is "maybe" turned on and off with the light switch and then either switched on and off with the fan switch or regulated by a "dimmer" of some sort, like many fan "switches" are.
UNLESS this is a new kind of fan that has some sort of information running between the light and fan switches and the light on neutral (they would need batteries to accomplish this in this case I think,) then this is wired in a way that doesn't accomplish much but double switching the neutral which is bad in at least two ways.
Are you positive there and not 2 sets of white, black and copper running to the switch box? OR are there any red wires that make it back to the light box? Can you take a good picture of both the fan box and the switch box? That would help orient us and possibly determine what is really going on here.
Just a background note:
A lot of circuits wired like this use a "switch loop". That is where one Romex line is run from the fixture box (light box in your case) to the switch box. Then the white conductor is wrapped with black electrical tape on both ends. The white (with black electrical tape) is connected to the black conductor (hot) in the fixture box and one side of the light switch. Then the black conductor is connected to the black conductor of the light. That is the "switch loop". It is JUST carrying the hot leg to the switch box to be switched. Everything else stays in the fixture box.
Further note:
Somewhere along the way we started connecting switches (or their metal boxes) in houses to ground as well. It has been that way a lot longer in commercial establishments. This may not be the case in your situation based on when the last wiring was completed to code. However, it appears you have a ground and that you should then make sure it is connected to the switch in the switch box OR its metal box to ground in the fixture box.
It seems in this case you would need 2 switch loops to properly make the light and fan work independently from the wall. IF it is possible that the fixture in question was not a fan at some point and ONLY a light, I would suggest you have encountered a non-electrically inclined person installing something they should not have. I have literally run into this twice. It can be easily fixed with a fan that is just given power (either directly OR through the switch loop) and controlled with a remote control or battery operated wall mounted controller. I actually have one of these in one of my rental apartments. Problem is the controller can bet misplaced. ha!
If you send some pics, I think we can give your electrician some theoretical advice on which way to go.
