There is a lot of fake products in the market, and sometimes the original products fail to protect electronic components from ESD.
My question is how do I test my gloves "with simple equipment" if it protect from ESD or not?
If you want to test for stay electric fields that may be occurring from materials that are not ESD compliant. Get or build an ESD Field Meter. They measure ambient electric fields and can help determine if there are stray fields that may be impacting your electronic environment.
There is now way to make this measurement "with simple equipment" (meaning low cost) as electric field meters need mechanical chopping and very very high input impedance amplifiers (which means that pretty much everything with the exception of teflon and kapton look like conductors to those types of amplifiers). By simple if you mean easy to use, then yes, ESD field meters are easy to use.
There are a few test I would do with regards to ESD qualities in a glove or finger cot: