Simplified example to demonstrate how to Mock a FileList for unit testing purposes.

Mock-FileList-for-Unit-Test-Angular2

// Method to test
public uploadFileList(files: FileList) {
 // whatever
}

// Test
it("uploadFileList", () => {
  const blob = new Blob([""], { type: "text/html" });
  blob["lastModifiedDate"] = "";
  blob["name"] = "filename";
  const file = <File>blob;
  const fileList = {
    0: file,
    1: file,
    length: 2,
    item: (index: number) => file
  };

  const spy = spyOn(service, "uploadFileList").and.returnValue([]);
  expect(service.uploadFileList(fileList)).toEqual([]);

});

Additional typing of blob was required.

interface iBlob extends Blob, File {
  name: string;
  lastModifiedDate: Date;
  lastModified: number;
  webkitRelativePathts: string;
}

const createFileFromMockFile = (file: MockFile): File => {
  const blob: Partial<iBlob> = new Blob([file.body], { type: file.mimeType });
  blob.lastModifiedDate = new Date();
  blob.name = file.name;
  blob.lastModified = Date.now();
  return blob as File;
};