This is a very common scenario. Spy on the function, trigger the event handler, then check that the spy was called.
describe("Blacklist exporting", function () {
it("exports on click", function () {
spyOn(window, "exportBlacklists");
$("#blacklists_csv_export").triggerHandler("click");
expect(window.exportBlacklists).toHaveBeenCalled();
});
});