Tests of General Relativity Using Black Hole X-ray Data

The theory of General Relativity has successfully passed a large number of observational tests. The theory has been extensively tested in the weak-field regime with experiments in the Solar System and observations of binary pulsars. Recently, there have seen significant advancements in the study of the strong-field regime, which can now be tested with gravitational waves, X-ray data, and mm Very-Long-Baseline Interferometry observations. Here we summarize the state of the art of the tests of General Relativity with black hole X-ray data, discussing its recent progress and future developments.