Testing iOS apps on attached device

[Ben Rubinstein]

It's taken me ages to get my system back together to do iOS development 
properly (forced to update phone, so then couldn't develop to it without 
latest xcode, but that required sierra, needed to not update to Sierra for a 
while.. bah).

So finally I've got my MacBook on Sierra, I've got Xcode 10.3, and LC 8.6.1, 
and I've gone through certificate hell, and it all works - I can build an iOS 
standalone, and use Xcode to install it on my phone.

But I can't use the "Test" function to test directly on my phone. If Test 
Target is set to Simulator, then Test works. But if I select my phone as Test 
Target, then Test causes a build process, but nothing happens on the phone.

Last time I had it all working ... it worked - there would be an update in the 
message box that went from 0% to 100% installed.

A very long time ago I recall installing Fruitstrap - maybe that's been 
neutered by updating to Sierra. What is now the approach to get "Test" working 
to direct deploy to an attached iOS device?

Many thanks,

Ben