Same file upload doesn't fire input event, even when clearing `input.value`

• @testing-library/user-event version: 12.8.2

• Testing Framework and version: jest 26.6.0
• DOM Environment: jsdom 16.4.0

Relevant code or config

const handleChange = jest.fn();
render(<InputComponent changeHandler={handleChange} />);
const inputEl = screen.getByLabelText("Select file") as HTMLInputElement;
const file = new File([], "image.jpg");
userEvent.upload(inputEl, file);
await waitFor(() => expect(handleChange).toBeCalled());

inputEl.value = "";
userEvent.upload(inputEl, file);
//fails
await waitFor(() => expect(handleChange).toBeCalledTimes(2));

What you did: In #575, upload was changed so it correctly doesn’t fire an onChange/onInput event when the same files are selected. In our use case, we do want it to fire again, and our workaround is adding an onClick event that sets inputEl.value = "".

What happened: Second input event doesn’t fire, even when the value is reset to blank.

Problem description: Looking at the source, it doesn’t appear to take value into account.

Suggested solution: It should consider the value of the input field, but I’m not sure how the value relates to input.files, which is what is normally used.

[lucaslcode]

jsdom seems to implement the correct behaviour for clearing: https://github.com/jsdom/jsdom/blob/bd50bbe219799980d9c9a173309cafcef3d9d8bc/lib/jsdom/living/nodes/HTMLInputElement-impl.js#L416

[ph-fritsche]

The issue has been resolved in #794

https://codesandbox.io/s/solitary-mountain-vlttj?file=/src/index.test.js