How to use the @vendure/core.OrderStateTransitionEvent function in @vendure/core

it('filters events with wrong order state', async () => {
            eventBus.publish(new OrderStateTransitionEvent('AddingItems', 'ArrangingPayment', ctx, order));
            await pause();
            expect(onSend).not.toHaveBeenCalled();

            eventBus.publish(new OrderStateTransitionEvent('AddingItems', 'Cancelled', ctx, order));
            await pause();
            expect(onSend).not.toHaveBeenCalled();

            eventBus.publish(new OrderStateTransitionEvent('AddingItems', 'PaymentAuthorized', ctx, order));
            await pause();
            expect(onSend).not.toHaveBeenCalled();

            eventBus.publish(new OrderStateTransitionEvent('ArrangingPayment', 'PaymentSettled', ctx, order));
            await pause();
            expect(onSend).toHaveBeenCalledTimes(1);
        });

it('sets the subject', async () => {
            eventBus.publish(new OrderStateTransitionEvent('ArrangingPayment', 'PaymentSettled', ctx, order));
            await pause();

            expect(onSend.mock.calls[0][0].subject).toBe(`Order confirmation for #${order.code}`);
        });
    });

it('filters events with wrong order state', async () => {
            eventBus.publish(new OrderStateTransitionEvent('AddingItems', 'ArrangingPayment', ctx, order));
            await pause();
            expect(onSend).not.toHaveBeenCalled();

            eventBus.publish(new OrderStateTransitionEvent('AddingItems', 'Cancelled', ctx, order));
            await pause();
            expect(onSend).not.toHaveBeenCalled();

            eventBus.publish(new OrderStateTransitionEvent('AddingItems', 'PaymentAuthorized', ctx, order));
            await pause();
            expect(onSend).not.toHaveBeenCalled();

            eventBus.publish(new OrderStateTransitionEvent('ArrangingPayment', 'PaymentSettled', ctx, order));
            await pause();
            expect(onSend).toHaveBeenCalledTimes(1);
        });

it('filters events with wrong order state', async () => {
            eventBus.publish(new OrderStateTransitionEvent('AddingItems', 'ArrangingPayment', ctx, order));
            await pause();
            expect(onSend).not.toHaveBeenCalled();

            eventBus.publish(new OrderStateTransitionEvent('AddingItems', 'Cancelled', ctx, order));
            await pause();
            expect(onSend).not.toHaveBeenCalled();

            eventBus.publish(new OrderStateTransitionEvent('AddingItems', 'PaymentAuthorized', ctx, order));
            await pause();
            expect(onSend).not.toHaveBeenCalled();

            eventBus.publish(new OrderStateTransitionEvent('ArrangingPayment', 'PaymentSettled', ctx, order));
            await pause();
            expect(onSend).toHaveBeenCalledTimes(1);
        });

import {
    AccountRegistrationEvent,
    Customer,
    IdentifierChangeRequestEvent,
    Order,
    OrderItem,
    OrderLine,
    OrderStateTransitionEvent,
    PasswordResetEvent,
    ProductVariant,
    User,
} from '@vendure/core';

export const mockOrderStateTransitionEvent = new OrderStateTransitionEvent(
    'ArrangingPayment',
    'PaymentSettled',
    {} as any,
    new Order({
        id: '6',
        createdAt: '2018-10-31T15:18:29.261Z',
        updatedAt: '2018-10-31T15:24:17.000Z',
        code: 'T3EPGJKTVZPBD6Z9',
        state: 'ArrangingPayment',
        active: true,
        customer: new Customer({
            id: '3',
            firstName: 'Test',
            lastName: 'Customer',
            emailAddress: 'test@test.com',
        }),