I have a React component to upload files. Below is part of the code that handles the file selection and once files are selected, it will display thumbnails.

I want to use RTL to test the file selection: clicking button which is EvidenceUploaderPanel, this opens the file selector input element, then choosing files.

This will also make the requests to upload the files as they are selected.

But I have no idea how to start.

function UploadScreen({
  title,
  maxNumberOfUploadFiles = 3,
  acceptedFileTypes,
}: Props) {
  const [documents, setDocuments] = useState<FileObject[]>([]);


  const handleFileSelection = (files: FileList) => {

    const documentsWithThumbnails = Array.from(files).map((file) => {
      // here I also make a request to upload each file.
      return {
        file,
        thumbnailURL: URL.createObjectURL(file),
        name: file.name,
      };
    });
    setDocuments((currentDocuments) => [...currentDocuments, ...documentsWithThumbnails]);
  };

  const inputRef = useRef(
    (() => {
      const element = document.createElement('input');
      element.multiple = true;
      element.type = 'file';
      element.accept = acceptedFileTypes?.join(',') || IMAGE_MIME_TYPES.join(',');
      element.addEventListener('change', () => {
        if (element.files && documents.length + element.files.length < maxNumberOfUploadFiles) {
          handleFileSelection(element.files);
          element.value = '';
        }
      });

      return element;
    })(),
  );


  const handleOpenFileClicker = () => {
    inputRef.current.click();
  };

  return (
    <div>
      <h2 className="container">{title}</h2>
       {documents.length > 0 ? (
        <section>
          <div className="body-text">
           Add files
          </div>
          <div className="thumbnail-container">
            {documents.map((doc) => {
              return (
                <BaseThumbnail
                  src={doc?.thumbnailURL}
                  key={doc.name}
                  deleteAction={() => {
                    deleteDocument(doc.name);
                  }}
                />
              );
            })}
          </div>
          <Link onPress={handleOpenFileClicker}>
            Add photos
          </Link>
        </section>
      ) : (
        <section>
          <div className="text">
            Add files
          </div>
          <div className="upload-container" />
          <EvidenceUploaderPanel
            labelText="upload files"
            openFilePicker={handleOpenFileClicker}
          />
        </section>
       )}
    </div>
  );
}