As of v0.18.1 I can use `test_bitcoin-qt -platform cocoa` to run GUI tests; this opens and closes a regtest GUI a bunch of times.

As of master (6e4f6553913978fcdddba30e0bb6f97edcb12e80) it seems to ignore the `-platform cocoa` and just run the test as with `minimal`.

As seen on macOS 10.14.6. Git bisect blames a2714a5c69f0b0506689af04c3e785f71ee0915d in #16578 `Do not pass in command line arguments to QApplication` (@achow101, @ryanofsky)
{
#ifdef Q_OS_MAC
    if (QApplication::platformName() == "minimal") {
        
        
        
        
        QWARN("Skipping WalletTests on mac build with 'minimal' platform set due to Qt bugs. To run AppTests, invoke "
              "with 'QT_QPA_PLATFORM=cocoa test_bitcoin-qt' on mac, or else use a linux or windows build.");
        return;
    }
#endif
    TestGUI();
}