Tests sharing the same power function

Let $X_1, X_2$ be a random sample from a distribution having probability density function $f_{\theta}(x) = \begin{cases} \frac{1}{\theta} e^{-\frac{x}{\theta}} & \text{if } x > 0 \ 0 & \text{otherwise} \end{cases}$, where $\theta \in (0, \infty)$ is an unknown parameter. For testing $H_0: \theta \le 1$ against $H_1: \theta > 1$, consider the test $\phi(X_1, X_2) = \begin{cases} 1 & \text{if } X_1 > 1 \ 0 & \text{otherwise} \end{cases}$. Then which one of the following tests has the same power function as $\phi$?