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)
#include <qt/recentrequeststablemodel.h>
#include <qt/receiverequestdialog.h>
#include <memory>
#include <QAbstractButton>
#include <QAction>
#include <QApplication>
#include <QCheckBox>
#include <QPushButton>
#include <QTimer>
#include <QVBoxLayout>
#include <QTextEdit>
#include <QListView>
#include <QDialogButtonBox>
namespace
{
void ConfirmSend(QString* text = nullptr, bool cancel = false)
{
    QTimer::singleShot(0, [text, cancel]() {
        for (QWidget* widget : QApplication::topLevelWidgets()) {
            if (widget->inherits("SendConfirmationDialog")) {
                SendConfirmationDialog* dialog = qobject_cast<SendConfirmationDialog*>(widget);
                if (text) *text = dialog->text();
                QAbstractButton* button = dialog->button(cancel ? QMessageBox::Cancel : QMessageBox::Yes);
                button->setEnabled(true);
                button->click();
            }
        }
    });
}
uint256 SendCoins(CWallet& wallet, SendCoinsDialog& sendCoinsDialog, const CTxDestination& address, CAmount amount, bool rbf)