Added constant EMPTY_OBJECT (an empty sealed object) that is used to indicate to the xml library that an empty XML element should be generated, and use it in the JSON hardcoded into the tests.

src/file/table/grid.spec.ts

@@ -4,6 +4,8 @@ import { Formatter } from "export/formatter";
 
 import { GridCol, TableGrid } from "./grid";
 
+import { EMPTY_OBJECT } from "file/xml-components";
+
 describe("GridCol", () => {
     describe("#constructor", () => {
         it("sets the width attribute to the value given", () => {
@@ -17,7 +19,7 @@ describe("GridCol", () => {
         it("does not set a width attribute if not given", () => {
             const grid = new GridCol();
             const tree = new Formatter().format(grid);
-            expect(tree).to.deep.equal({ "w:gridCol": {} });
+            expect(tree).to.deep.equal({ "w:gridCol": EMPTY_OBJECT });
         });
     });
 });