Function createFileSystemFileHandle

src/index.spec.js:3802–3804

* createFileSystemFileHandle creates a mock [FileSystemFileHandle](https://developer.mozilla.org/en-US/docs/Web/API/FileSystemFileHandle) * @param {File} file

(file)

 * @param {File} file
 */
function createFileSystemFileHandle(file) {
  return { getFile: () => Promise.resolve(file) };
}

/**
 * createFile creates a mock File object