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var assert = require("assert")
var UndoStack = require("../public/assets/javascripts/rectangles/util/undo.js")
UndoStack.debug = false
describe('undo', function(){
var state = "zero"
describe('#register()', function(){
UndoStack.register({
type: "demo",
undo: function(myState){
state = myState
},
redo: function(myState){
state = myState
},
})
it('registers undoable actions', function(){
assert( UndoStack.types.hasOwnProperty("demo") )
})
})
describe('#push()', function(){
it('starts empty', function(){
assert.equal(0, UndoStack.stack.length)
assert.equal(-1, UndoStack.pointer)
})
it('pushes some actions', function(){
UndoStack.push({
type: "demo",
prev: state,
next: "one"
})
state = "one"
UndoStack.push({
type: "demo",
prev: state,
next: "two"
})
state = "two"
UndoStack.push({
type: "demo",
prev: state,
next: "three"
})
state = "three"
assert.equal(3, UndoStack.stack.length)
assert.equal(2, UndoStack.pointer)
})
})
describe('#undo()', function(){
it('retrieves old state', function(){
assert.equal("three", state)
UndoStack.undo()
assert.equal("two", state)
assert.equal(1, UndoStack.pointer)
})
it('can only undo so far', function(){
var canUndo
canUndo = UndoStack.undo()
assert.equal("one", state)
assert.equal(0, UndoStack.pointer)
assert.equal(true, canUndo)
canUndo = UndoStack.undo()
assert.equal("zero", state)
assert.equal(-1, UndoStack.pointer)
assert.equal(false, canUndo)
canUndo = UndoStack.undo()
assert.equal("zero", state)
assert.equal(-1, UndoStack.pointer)
assert.equal(false, canUndo)
})
})
describe('#redo()', function(){
it('reassigns new state', function(){
UndoStack.redo()
assert.equal("one", state)
})
it('can only redo so far', function(){
var canRedo
canRedo = UndoStack.redo()
assert.equal("two", state)
assert.equal(true, canRedo)
canRedo = UndoStack.redo()
assert.equal("three", state)
assert.equal(false, canRedo)
canRedo = UndoStack.redo()
assert.equal("three", state)
assert.equal(false, canRedo)
})
it('clobbers old state if we undo then do something else', function(){
UndoStack.undo()
assert.equal("two", state)
assert.equal(1, UndoStack.pointer)
UndoStack.undo()
assert.equal("one", state)
assert.equal(0, UndoStack.pointer)
assert.equal(3, UndoStack.stack.length)
UndoStack.push({
type: "demo",
prev: state,
next: "four"
})
state = "four"
assert.equal(1, UndoStack.pointer)
assert.equal(2, UndoStack.stack.length)
UndoStack.undo()
assert.equal("one", state)
assert.equal(0, UndoStack.pointer)
assert.equal(2, UndoStack.stack.length)
UndoStack.redo()
assert.equal("four", state)
assert.equal(1, UndoStack.pointer)
assert.equal(2, UndoStack.stack.length)
})
})
})
// 1) push action
// 2) push action
// 3) push action
// undo 3
// undo 2
// undo 1
// undo * can't undo anymore
// redo 1
// redo 2
// redo 3
// redo * can't redo anymore
// undo 3
// 4) push action (clobbers action 3)
// undo 4
// undo 2
// redo 2
// redo 4
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