gerich-home/it-depends

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

describe('computed with computed dependency', function () {
    var calls;
    var otherValue;
    var otherComputed;
    var computedValue;

    beforeEach(function(){
        var counter = { count: 0 };
        calls = counter;

        otherValue = itDepends.value('Bob');
        otherComputed = itDepends.computed(function(){
            return 'mr. ' + otherValue();
        });

        computedValue = itDepends.computed(function(){
            counter.count++;
            return 'Hello, ' + otherComputed();
        });
    });

    it('should not calculate when created', function () {
        expect(calls.count).to.equal(0);
    });

    it('should not calculate when computed dependency was calculated', function () {
        otherComputed();
        expect(calls.count).to.equal(0);
    });

    it('should not calculate when computed dependency was changed and recalculated', function () {
        otherValue.write('Jack');
        otherComputed();
        expect(calls.count).to.equal(0);
    });

    it('should calculate when requested', function () {
        var actualValue = computedValue();
        expect(actualValue).to.equal('Hello, mr. Bob');
        expect(calls.count).to.equal(1);
    });
    
    context('after was calculated once', function () {
        beforeEach(function(){
            computedValue();
        });

        it('should not calculate second time if computed dependency was not changed', function () {
            var actualValue = computedValue();
            expect(actualValue).to.equal('Hello, mr. Bob');
            expect(calls.count).to.equal(1);
        });

        it('should not calculate when computed dependency was calculated', function () {
            otherComputed();
            expect(calls.count).to.equal(1);
        });

        context('after computed dependency was changed', function () {
            beforeEach(function(){
                otherValue.write('Jack');
            });
            
            context('after computed dependency was recalculated and changed back immediatelly', function () {
                beforeEach(function(){
                    otherComputed();
                    otherValue.write('Bob');
                });

                it('should not recalculate when requested', function () {
                    var actualValue = computedValue();
                    expect(actualValue).to.equal('Hello, mr. Bob');
                    expect(calls.count).to.equal(1);
                });
            });
            
            it('should not recalculate after computed dependency was recalculated', function () {
                otherComputed();
                expect(calls.count).to.equal(1);
            });

            it('should calculate when requested', function () {
                var actualValue = computedValue();
                expect(actualValue).to.equal('Hello, mr. Jack');
                expect(calls.count).to.equal(2);
            });
        });
    });
    
    context('after computed dependency was changed', function () {
        beforeEach(function(){
            otherValue.write('Jack');
        });
        
        it('should not recalculate after computed dependency was recalculated', function () {
            otherComputed();
            expect(calls.count).to.equal(0);
        });

        it('should calculate when requested', function () {
            var actualValue = computedValue();
            expect(actualValue).to.equal('Hello, mr. Jack');
            expect(calls.count).to.equal(1);
        });
    
        context('after was calculated once', function () {
            beforeEach(function(){
                computedValue();
            });

            it('should not calculate second time if computed dependency was not changed', function () {
                var actualValue = computedValue();
                expect(actualValue).to.equal('Hello, mr. Jack');
                expect(calls.count).to.equal(1);
            });
        });
    });
});