Add and fix unittests for NAS

[graykode]

21

I compared both the list_object function of minio and the list_object function that I directly override(NAS class). At this time, only when the prefix is'metadata/test/', there is a problem that the two do not match. Be careful about this.

Add unittests for NAS

• data saver and data loader
• model saver and model loader
• optimizer saver and optimizer loader

As one problem, we found a problem that unittest.skip cannot be called in the same class. Therefore, this stackoverflow answer solved this.

[graykode]

todo

• https://github.com/graykode/matorage/pull/29/commits/e43fd939bacbee935c11a2b4db0bed8c503928c5 : Unlike pytorch, tensorflow cannot upload a model twice. Therefore, the unittest function related to reload was removed. To make this possible, it is necessary to divide it into a train process using multiprocess and an eval process that reloads it after training. Previously, it was not a problem because you did not enter this function with unittest.skip, but when entering, a deadlock occurs in the join of the multiprocess.
• Due to this deadlock, unittest from https://github.com/graykode/matorage/pull/29/commits/4c56bfa847ba783c98a038e0017a6db1bfc81b89 to https://github.com/graykode/matorage/pull/29/commits/f2bbec817ad8b2580154d4987c55b649c0ffb959 (timeout error in travis ci)

Therefore, in the case of reloading of tensorflow model, it is a todo problem that needs to be fixed someday.