Add testids to prev and next month buttons

Author: hoorayimhelping

src/components/DatePicker/Common.tsx

@@ -277,13 +277,15 @@ export const CalendarRenderer = ({
         orientation="horizontal"
       >
         <IconButton
+          data-testid="calendar-previous-month"
           icon="chevron-left"
           onClick={handlePreviousClick}
           size="sm"
           type="ghost"
         />
         <UnselectableTitle>{headerDateFormatter.format(headerDate)}</UnselectableTitle>
         <IconButton
+          data-testid="calendar-next-month"
           icon="chevron-right"
           onClick={handleNextClick}
           size="sm"