Okay, I just discovered a site called Terra Server which features satellite photos from various commercial satellite operators that are very up to date and can be viewed, but with watermarks. BTW, the recent image from JNCX of the 055 hull was also probably taken from Terra Server, by someone who probably bought the image themselves considering the quality.
This image of huangdicun is from october 24 (taken by company digital globe); it looks completed, despite the low resolution and relatively plentiful watermarks (not purchased; screenshot), both catapults look pretty damn finished.
Of course we don't know when they reached that state, but based on the chronology of satellite images of Huangdicun, which goes back to October 17 being the earliest at this year (previously early being 2013), it already looked completed by then. In reality it was probably completed a bit earlier.
So based on this, it is
very plausible that a J-15A could've been tested at the EM cat recently, given the state of completion the site looks like in the last month or so.
Now to wait for GE to update...