  The Leggett-Garg (LG) test of macroscopic realism involves a series of
dichotomic non-invasive measurements that are used to calculate a function
which has a fixed upper bound for a macrorealistic system and a larger upper
bound for a quantum system. The quantum upper bound depends on both the details
of the measurement and the dimension of the system. Here we present an LG
experiment on a three-level quantum system, which produces a larger theoretical
quantum upper bound than that of a two-level quantum system. The experiment is
carried out in nuclear magnetic resonance (NMR) and consists of the LG test as
well as a test of the ideal assumptions associated with the experiment, such as
measurement non-invasiveness. The non-invasive measurements are performed via
the modified ideal negative result measurement scheme on a three-level system.
Once these assumptions are tested, the violation becomes small, despite the
fact that the LG value itself is large. Our results showcase the advantages of
using the modified measurement scheme that can reach the higher LG values, as
they give more room for hypothetical malicious errors in a real experiment
