gerich-home/it-depends

var expect = require('chai').expect;
var itDepends = require('../out/build/it-depends.js');

describe('usage of the library in the real world scenarios', function () {
    context('conditional computeds', function () {
        var a;
        var b;
        var c;
        var d;
        var calls;
        
        beforeEach(function() {
            var counter = { count: 0 };
            calls = counter;
            
            a = itDepends.value(1);
            b = itDepends.value(2);
            c = itDepends.value(3);
            
            d = itDepends.computed(function() {
                ++counter.count;
                if(a() === 1) {
                    return b();
                }
                else {
                    return c();
                }
            });
        });
            
        it('should not recalculate immediately', function () {
            expect(calls.count).to.equal(0);
        });
            
        it('should recalculate when requested', function () {
            var actualValue = d();
            
            expect(actualValue).to.equal(2);
            expect(calls.count).to.equal(1);
        });
        
        context('after changes are made', function () {        
            beforeEach(function() {
                a.write(4);
                b.write(5);
                c.write(6);
            });
            
            it('should not recalculate immediately', function () {
                expect(calls.count).to.equal(0);
            });
            
            it('should recalculate once when requested', function () {
                var actualValue = d();
                
                expect(actualValue).to.equal(6);
                expect(calls.count).to.equal(1);
            });
            
            it('should not recalculate when requested second time', function () {
                d();
                var actualValue = d();
                
                expect(actualValue).to.equal(6);
                expect(calls.count).to.equal(1);
            });
        });
        
        context('after was requested', function () {        
            beforeEach(function() {
                d();
            });
            
            it('should not recalculate when requested after a change is made to false condition branch variable', function () {
                c.write(6);

                var actualValue = d();
                
                expect(actualValue).to.equal(2);
                expect(calls.count).to.equal(1);
            });
        });
    });
    
    context('depending on the same value multiple times', function () {
        var a;
        var b;
        var c;
        var calls;
        
        beforeEach(function() {
            var counter = { count: 0 };
            calls = counter;
            
            a = itDepends.value(4);
            b = itDepends.value(5);
            
            c = itDepends.computed(function() {
                ++counter.count;
                if(b() - a() === 1) {
                    return a();
                }
                else {
                    return b();
                }
            });
        });
            
        it('should not recalculate immediately', function () {
            expect(calls.count).to.equal(0);
        });
            
        it('should recalculate when requested', function () {
            var actualValue = c();
            
            expect(actualValue).to.equal(4);
            expect(calls.count).to.equal(1);
        });
        
        context('after change is made', function () {        
            beforeEach(function() {
                a.write(3);
            });
            
            it('should not recalculate immediately', function () {
                expect(calls.count).to.equal(0);
            });
            
            it('should recalculate once when requested', function () {
                var actualValue = c();
                
                expect(actualValue).to.equal(5);
                expect(calls.count).to.equal(1);
            });
            
            it('should not recalculate when requested second time', function () {
                c();
                var actualValue = c();
                
                expect(actualValue).to.equal(5);
                expect(calls.count).to.equal(1);
            });
        });
        
        context('after was requested and a change is made', function () {        
            beforeEach(function() {
                c();
                a.write(3);
            });
            
            it('should recalculate once when requested', function () {
                var actualValue = c();
                
                expect(actualValue).to.equal(5);
                expect(calls.count).to.equal(2);
            });
            
            it('should not recalculate when requested second time', function () {
                c();
                var actualValue = c();
                
                expect(actualValue).to.equal(5);
                expect(calls.count).to.equal(2);
            });
        });
    });
    
    context('diamond dependencies', function () {
        it('should work', function() {
            var dependenciesCount = 3;
            var updatesCount = 3;
            
            var x = [];
            for (var j = 0; j < dependenciesCount; j++) {
                x.push(itDepends.value(j));
            }

            var a = itDepends.computed(function() {
                var z = 0;
                for (var j = 0; j < dependenciesCount; j++) {
                    z += x[j]();
                }
                return z;
            });

            var b = itDepends.computed(function() {
                return a();
            });

            var c = itDepends.computed(function() {
                return a();
            });

            var d = itDepends.value(-1);

            var e = itDepends.computed(function() {
                return d() % 2 == 0 ? b() : c();
            });

            var s = e.onChange(function(){
                
            });
            
            for (var j = 0; j < updatesCount; j++) {
                d.write(j);
            }
        });
    });
});