This solution returns f(0) = 1, which contradicts the decription of the given problem.

This solution uses filter from the Signal Processing Toolbox.

Yes, it uses filter, but filter is indeed not a toolbox function, but a built-in function. You can fix the error by changing f=y(n-2) to f = y(n)

... and then change first input of filter to [1,-1] and remove +1 from the end of the line.

Test suite is flawed. I had to add a round(x,0) function to the output to make it pass.

Test is correct. Fibonacci Numbers are integers, so your output should be to.