In general, you will find the "ideal" cases simply do not exist. You cannot make a wire of zero resistance, so all of the nice easy simple equations you are learning will not apply. This is similar to the argument made when you construct an "ideal" circuit short circuiting a battery. The simplified laws just fall short.
However, in this particular case, there is a practical example of this: superconducting electromagnets. Superconducting materials do indeed have exactly zero resistance. Superconducting electromagnets can be incredibly powerful. They don't waste any energy on resistance of the wires in the magnet's coils, so you can reach more extreme magnetic fields.
If you hook a battery up to one of these coils, it basically will act like a short. You'll see the internal resistance of the battery, resistance of the feeder wires, and that's it. The superconducting section simply wont add any resistance to the story.
So when they charge up one of these superconducting magnets, what they end up doing is first creating a loop through the power source. They cool down the magnet until the material superconducts, and then they start driving it with the power source. This current is limited by something called "inductance," which you will learn about. Eventually the power source will have built up the magnetic field to the desired point. At this point, a superconducting shunt is placed across where the power source is feeding the superconductor. Once this is done, you can remove the power source, and you have a superconducting loop, which goes on forever, because it has zero resistence.
Well, almost forever Eventually magnetic coupling with the rest of the world will transfer energy out of the coil, or the coil may "quench," which causes it to cease to superconduct. But for the purposes you are looking at, the electromagnetic fields will simply propagate energy forever around the loop.