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)
{
    
    
    
    
    
    
    {
        BasicTestingSetup dummy{CBaseChainParams::REGTEST};
    }
    auto node = interfaces::MakeNode();
    bool fInvalid = false;
    
    
    
    #if defined(WIN32)
        _putenv_s("QT_QPA_PLATFORM", "minimal");
    #else
        setenv("QT_QPA_PLATFORM", "minimal",  0);
    #endif
    
    
    BitcoinApplication app(*node);
    app.setApplicationName("Bitcoin-Qt-test");
    AppTests app_tests(app);
    if (QTest::qExec(&app_tests) != 0) {
        fInvalid = true;
    }
    URITests test1;