  To show an internal signature of gravitational lensing, two different
temporal sections of a single gamma-ray burst (GRB) must be statistically
similar. Here two straightforward gravitational lensing tests are defined and
applied: a light-curve similarity test and a hardness similarity test.
Gravitational millilensing has been claimed to be detected within several
individual GRBs that contain two emission episodes separated by a time delay.
However, our analyses indicate that none of those claims clearly satisfy both
tests. The hardness similarity test performed on GRB 950830 and GRB 090717A
found that the ratio between the second and the first emission episodes in each
energy channel differed from the same ratio averaged over all detected energy
channels at above the 90 percent confidence level. Also, a light curve
similarity test performed on GRB 950830, GRB 090717A, and GRB 200716C
separately, found that it is unlikely that the two emission episodes in each
GRB were drawn from a single parent emission episode for that GRB, with
differences at the 3.0 sigma, 8.3 sigma, and 8.3 sigma confidence levels
respectively.
