FireEvent to simulate user operation

1. fireEvent

   fireEvent was originally in the @testing-library/dom package, but @testing-library/react rewrote it and gave it additional React-specific functionality. It can simulate user actions to trigger events.

   
   

2. usage

   instruction	event
   fireEvent.click(DOM)	mouse click on the DOM
   fireEvent.change(input, { target: { value: “x” } });	User enters x
   fireEvent.mouseOver(DOM);	Move the mouse into the DOM
   fireEvent.keyPress(inputEl, { key: “Enter”, code: “Enter”, charCode: 13 });	keyboard press event

   Note that in fireEvent.change(input, { target: { value: "x" } });, '' should be used here even if the input format is a number.