it("returns the values from a string map if categories are not given", () => {
   const stringMap = {x: {"a": 1, "b": 2, "c": 3}};
   const categories = {};
   const tickResult = Helpers.getTicksFromData({categories, stringMap}, "x");
   expect(tickResult).to.eql([1, 2, 3]);
 });
 it("returns undefined if neither a string map or categories are given", () => {
   const stringMap = {};
   const categories = {};
   const tickResult = Helpers.getTicksFromData({categories, stringMap}, "x");
   expect(tickResult).to.be.undefined;
 });
 it("returns a category array if there is one", () => {
   const categories = {x: [1, 2, 3]};
   const stringMap = {x: {"a": 1, "b": 2, "c": 3}};
   const tickResult = Helpers.getTicksFromData({categories, stringMap}, "x");
   expect(tickResult).to.eql(categories.x);
 });