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As part of a systematic deep imaging survey with CFHT+MegaCam comma 96 ultra-diffuse galaxies (UDGs) in low to medium density fields have been identified. This UDG dataset is among the largest sample of this type of galaxy outside of galaxy clusters. Thanks to the high image quality of MegaCam comma part of their globular clusters (GCs) population can already be detected and two populations of UDGs have been identifieddoublePoint one with an excess number and the other with a similar number of GCs compared to normal dwarfs. This GC candidate selection method was proven reliable for a UDG in the NGC 5846 group comma using HST data that sampled most of the GCLF. This most extreme UDG hosts 40 GCs and a vast dark matter (DM) halo as massive as the Large Magellanic Cloud comma but is less luminous by a factor of 50 comma i.e. comma is too massive for its stellar mass. However comma VLT+MUSE spectroscopy suggests that based on the stellar velocity dispersion comma this UDG hosts a rather small DM halo. Many of these properties are similar to those of the UDGs NGC1052-DF2 and -DF4 which comma however comma appear to have over-luminous GCs. This reveals a tension between the two different paths to measure the DM mass of a dwarf. We propose a SNAPSHOT program of 70 UDGs in non-cluster environments comma employing two-band ACS imaging to trace the full population of GCs 3 magnitudes below the peak of the GCLF and give us an accurate estimate of the total number of GCs. We will characterize their GC systems and test whether some UDGs host an exceptionally large number of GCs comma but with a regular GCLF comma or contain a population consisting of only over-luminous GCs. Both cases pose a conundrum for our undertanding of GC and galaxy formation.