Why does this not converge uniformly? (fourier series)

Question

Given the function
$$f(x) =\begin{cases} 0, & \text{if } -\pi \leq x \leq 0,\\ 1, & \text{if } 0 < x \leq \pi. \end{cases}$$
The fourier series for this is
$$Sf(x) = \frac{1}{2} + \frac{2}{\pi} \sum_{k=1}^{\infty} \frac{\sin (2k-1)x}{2k-1}.$$
It asks me does $Sf(x)$ converge uniformly for $-\pi \leq x \leq \pi$. It says it doesn't, but I'm not sure of a quick way to do this. I also am not sure if I can use the definition either, as it'll still give me a series starting at $k=n+1$ to $\infty$.