test_undoStack.js - mozsearch

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/* Any copyright is dedicated to the Public Domain.

   http://creativecommons.org/publicdomain/zero/1.0/ */

"use strict";

const { UndoStack } = require("resource://devtools/client/shared/undo.js");

const MAX_SIZE = 5;

function run_test() {

  let str = "";

  const stack = new UndoStack(MAX_SIZE);

  function add(ch) {

    stack.do(

      function () {

        str += ch;

},

      function () {

        str = str.slice(0, -1);

);

  Assert.ok(!stack.canUndo());

  Assert.ok(!stack.canRedo());

  // Check adding up to the limit of the size

  add("a");

  Assert.ok(stack.canUndo());

  Assert.ok(!stack.canRedo());

  add("b");

  add("c");

  add("d");

  add("e");

  Assert.equal(str, "abcde");

  // Check a simple undo+redo

  stack.undo();

  Assert.equal(str, "abcd");

  Assert.ok(stack.canRedo());

  stack.redo();

  Assert.equal(str, "abcde");

  Assert.ok(!stack.canRedo());

  // Check an undo followed by a new action

  stack.undo();

  Assert.equal(str, "abcd");

  add("q");

  Assert.equal(str, "abcdq");

  Assert.ok(!stack.canRedo());

  stack.undo();

  Assert.equal(str, "abcd");

  stack.redo();

  Assert.equal(str, "abcdq");

  // Revert back to the beginning of the queue...

  while (stack.canUndo()) {

    stack.undo();

  Assert.equal(str, "");

  // Now put it all back....

  while (stack.canRedo()) {

    stack.redo();

  Assert.equal(str, "abcdq");

  // Now go over the undo limit...

  add("1");

  add("2");

  add("3");

  Assert.equal(str, "abcdq123");

  // And now undoing the whole stack should only undo 5 actions.

  while (stack.canUndo()) {

    stack.undo();

  Assert.equal(str, "abc");