code: public void dryrunByGivenText(String subject, String plainBody, String htmlBody) {
          postcard.dryrun();
          postcard.overrideBodyFile(subject, plainBody).alsoHtmlBody(htmlBody);
      }
docs: Set up as dry-run by given text. <br>
  Not send it actually, only preparation, e.g. for preview. <br>
  You can get complete plain or HTML text from postcard.
  @param subject The subject as given text. (NotNull)
  @param plainBody The plain body (template) as given text. (NotNull)
  @param htmlBody The HTML body (template) as given text. (NotNull)