  The continuum-fitting and the iron line methods are currently the two leading
techniques for probing the strong gravity region around accreting black holes.
In the present work, we test the Kerr black hole hypothesis with the
stellar-mass black hole in GRS 1915+105 by analyzing five disk-dominated RXTE
spectra and one reflection-dominated Suzaku spectrum. The combination of the
constraints from the continuum-fitting and the iron line methods has the
potential to provide more stringent tests of the Kerr metric. Our constraint on
the Johannsen deformation parameter $\alpha_{13}$ is $-0.15 < \alpha_{13} <
0.14$ at 3$\sigma$, where the Kerr metric is recovered when $\alpha_{13} = 0$.
