It doesn't sound like you actually read the post. If you had, the post tells you that the black vent provides bypass air for starting. The post states that the black vent version is less likely to die when the electrical line is disconnected. The key thing the basic functional test is looking for is the CHANGE(lower) in RPM's. No change equals no IAC function.
Since you have now confirmed the black vent version, do yourself a favor and buy a new one. The black vent version can not be effectively cleaned.
If you still still wish to test, an ODB2 scanner with the ability to monitor operational parameters will be needed.
Again, as mentioned before, there are multiple reasons for a slow idle. Tests are needed to rule in/out the various causes. Sometimes you just need to start at the most likely place and work from there.
OBTW, should you decide to clean the black vent IAC, please don't post any requests for more help should it not work. Note, I am not going to tell you with absolute certaintaty it won't work because sometimes it does. However, the odds favor the results to be only temporary. Or one set of problems will be traded for another.
Good luck.