@silverbirder/rminc/dist/user/mail/mailMessage/mailMessageMock.d.ts

rMinc is the Google Apps Script Library that register Mail in Calendar

import IMailMessage from "./iMailMessage";
export default class MailMessageMock implements IMailMessage {
    subject: string;
    body: string;
    date: Date;
    getSubject(): string;
    getBody(): string;
    getDate(): Date;
}