templatingBehaviors.js

var dummyTemplateEngine = function (templates) {
    var inMemoryTemplates = templates || {};
    var inMemoryTemplateData = {};

    function dummyTemplateSource(id) {
        this.id = id;
    }
    dummyTemplateSource.prototype = {
        text: function(val) {
            if (arguments.length >= 1)
                inMemoryTemplates[this.id] = val;
            return inMemoryTemplates[this.id];
        },
        data: function(key, val) {
            if (arguments.length >= 2) {
                inMemoryTemplateData[this.id] = inMemoryTemplateData[this.id] || {};
                inMemoryTemplateData[this.id][key] = val;
            }
            return (inMemoryTemplateData[this.id] || {})[key];
        }
    }

    this.makeTemplateSource = function(template) {
        if (typeof template == "string")
            return new dummyTemplateSource(template); // Named template comes from the in-memory collection
        else if ((template.nodeType == 1) || (template.nodeType == 8))
            return new ko.templateSources.anonymousTemplate(template); // Anonymous template
    };

    this.renderTemplateSource = function (templateSource, bindingContext, options, templateDocument) {
        var data = bindingContext['$data'];
        templateDocument = templateDocument || document;
        options = options || {};
        var templateText = templateSource.text();
        if (typeof templateText == "function")
            templateText = templateText(data, options);

        templateText = options.showParams ? templateText + ", data=" + data + ", options=" + options : templateText;
        var templateOptions = options.templateOptions; // Have templateOptions in scope to support [js:templateOptions.foo] syntax

        var result;
        with (bindingContext) {
            with (data || {}) {
                with (options.templateRenderingVariablesInScope || {}) {
                    // Dummy [renderTemplate:...] syntax
                    result = templateText.replace(/\[renderTemplate\:(.*?)\]/g, function (match, templateName) {
                        return ko.renderTemplate(templateName, data, options);
                    });


                    var evalHandler = function (match, script) {
                        try {
                            var evalResult = eval(script);
                            return (evalResult === null) || (evalResult === undefined) ? "" : evalResult.toString();
                        } catch (ex) {
                            throw new Error("Error evaluating script: [js: " + script + "]\n\nException: " + ex.toString());
                        }
                    }

                    // Dummy [[js:...]] syntax (in case you need to use square brackets inside the expression)
                    result = result.replace(/\[\[js\:([\s\S]*?)\]\]/g, evalHandler);

                    // Dummy [js:...] syntax
                    result = result.replace(/\[js\:([\s\S]*?)\]/g, evalHandler);
                }
            }
        }

        // Use same HTML parsing code as real template engine so as to trigger same combination of IE weirdnesses
        // Also ensure resulting nodelist is an array to mimic what the default templating engine does, so we see the effects of not being able to remove dead memo comment nodes.
        return ko.utils.arrayPushAll([], ko.utils.parseHtmlFragment(result, templateDocument));
    };

    this.rewriteTemplate = function (template, rewriterCallback, templateDocument) {
        // Only rewrite if the template isn't a function (can't rewrite those)
        var templateSource = this.makeTemplateSource(template, templateDocument);
        if (typeof templateSource.text() != "function")
            return ko.templateEngine.prototype.rewriteTemplate.call(this, template, rewriterCallback, templateDocument);
    };
    this.createJavaScriptEvaluatorBlock = function (script) { return "[js:" + script + "]"; };
};
dummyTemplateEngine.prototype = new ko.templateEngine();

describe('Templating', function() {
    beforeEach(jasmine.prepareTestNode);
    afterEach(function() {
        ko.setTemplateEngine(new ko.nativeTemplateEngine());
    });

    it('Template engines can return an array of DOM nodes', function () {
        ko.setTemplateEngine(new dummyTemplateEngine({ x: [document.createElement("div"), document.createElement("span")] }));
        ko.renderTemplate("x", null);
    });

    it('Should not be able to render a template until a template engine is provided', function () {
        expect(function () {
            ko.setTemplateEngine(undefined);
            ko.renderTemplate("someTemplate", {});
        }).toThrow();
    });

    it('Should be able to render a template into a given DOM element', function () {
        ko.setTemplateEngine(new dummyTemplateEngine({ someTemplate: "ABC" }));
        ko.renderTemplate("someTemplate", null, null, testNode);
        expect(testNode.childNodes.length).toEqual(1);
        expect(testNode.innerHTML).toEqual("ABC");
    });

    it('Should be able to render an empty template', function() {
        ko.setTemplateEngine(new dummyTemplateEngine({ emptyTemplate: "" }));
        ko.renderTemplate("emptyTemplate", null, null, testNode);
        expect(testNode.childNodes.length).toEqual(0);
    });

    it('Should be able to access newly rendered/inserted elements in \'afterRender\' callback', function () {
        var passedElement, passedDataItem;
        var myCallback = function(elementsArray, dataItem) {
            expect(elementsArray.length).toEqual(1);
            passedElement = elementsArray[0];
            passedDataItem = dataItem;
        }
        var myModel = {};
        ko.setTemplateEngine(new dummyTemplateEngine({ someTemplate: "ABC" }));
        ko.renderTemplate("someTemplate", myModel, { afterRender: myCallback }, testNode);
        expect(passedElement.nodeValue).toEqual("ABC");
        expect(passedDataItem).toEqual(myModel);
    });

    it('Should automatically rerender into DOM element when dependencies change', function () {
        var dependency = new ko.observable("A");
        ko.setTemplateEngine(new dummyTemplateEngine({ someTemplate: function () {
            return "Value = " + dependency();
        }
        }));

        ko.renderTemplate("someTemplate", null, null, testNode);
        expect(testNode.childNodes.length).toEqual(1);
        expect(testNode.innerHTML).toEqual("Value = A");

        dependency("B");
        expect(testNode.childNodes.length).toEqual(1);
        expect(testNode.innerHTML).toEqual("Value = B");
    });

    it('Should not rerender DOM element if observable accessed in \'afterRender\' callback is changed', function () {
        var observable = new ko.observable("A"), count = 0;
        var myCallback = function(elementsArray, dataItem) {
            observable();   // access observable in callback
        };
        var myTemplate = function() {
            return "Value = " + (++count);
        };
        ko.setTemplateEngine(new dummyTemplateEngine({ someTemplate: myTemplate }));
        ko.renderTemplate("someTemplate", {}, { afterRender: myCallback }, testNode);
        expect(testNode.childNodes.length).toEqual(1);
        expect(testNode.innerHTML).toEqual("Value = 1");

        observable("B");
        expect(testNode.childNodes.length).toEqual(1);
        expect(testNode.innerHTML).toEqual("Value = 1");
    });

    it('If the supplied data item is observable, evaluates it and has subscription on it', function () {
        var observable = new ko.observable("A");
        ko.setTemplateEngine(new dummyTemplateEngine({ someTemplate: function (data) {
            return "Value = " + data;
        }
        }));
        ko.renderTemplate("someTemplate", observable, null, testNode);
        expect(testNode.innerHTML).toEqual("Value = A");

        observable("B");
        expect(testNode.innerHTML).toEqual("Value = B");
    });

    it('Should stop updating DOM nodes when the dependency next changes if the DOM node has been removed from the document', function () {
        var dependency = new ko.observable("A");
        var template = { someTemplate: function () { return "Value = " + dependency() } };
        ko.setTemplateEngine(new dummyTemplateEngine(template));

        ko.renderTemplate("someTemplate", null, null, testNode);
        expect(testNode.childNodes.length).toEqual(1);
        expect(testNode.innerHTML).toEqual("Value = A");

        testNode.parentNode.removeChild(testNode);
        dependency("B");
        expect(testNode.childNodes.length).toEqual(1);
        expect(testNode.innerHTML).toEqual("Value = A");
    });

    it('Should be able to pick template via an observable', function () {
        ko.setTemplateEngine(new dummyTemplateEngine({
            firstTemplate: "First template output",
            secondTemplate: "Second template output"
        }));

        var chosenTemplate = ko.observable("firstTemplate");
        ko.renderTemplate(chosenTemplate, null, null, testNode);
        expect(testNode.innerHTML).toEqual("First template output");

        chosenTemplate("secondTemplate");
        expect(testNode.innerHTML).toEqual("Second template output");
    });

    it('Should be able to render a template using data-bind syntax', function () {
        ko.setTemplateEngine(new dummyTemplateEngine({ someTemplate: "template output" }));
        testNode.innerHTML = "<div data-bind='template:\"someTemplate\"'></div>";
        ko.applyBindings(null, testNode);
        expect(testNode.childNodes[0].innerHTML).toEqual("template output");
    });

    it('Should remove existing content when rendering a template using data-bind syntax', function () {
        ko.setTemplateEngine(new dummyTemplateEngine({ someTemplate: "template output" }));
        testNode.innerHTML = "<div data-bind='template:\"someTemplate\"'><span>existing content</span></div>";
        ko.applyBindings(null, testNode);
        expect(testNode.childNodes[0].innerHTML).toEqual("template output");
    });

    it('Should be able to tell data-bind syntax which object to pass as data for the template (otherwise, uses viewModel)', function () {
        ko.setTemplateEngine(new dummyTemplateEngine({ someTemplate: "result = [js: childProp]" }));
        testNode.innerHTML = "<div data-bind='template: { name: \"someTemplate\", data: someProp }'></div>";
        ko.applyBindings({ someProp: { childProp: 123} }, testNode);
        expect(testNode.childNodes[0].innerHTML).toEqual("result = 123");
    });

    it('Should re-render a named template when its data item notifies about mutation', function () {
        ko.setTemplateEngine(new dummyTemplateEngine({ someTemplate: "result = [js: childProp]" }));
        testNode.innerHTML = "<div data-bind='template: { name: \"someTemplate\", data: someProp }'></div>";

        var myData = ko.observable({ childProp: 123 });
        ko.applyBindings({ someProp: myData }, testNode);
        expect(testNode.childNodes[0].innerHTML).toEqual("result = 123");

        // Now mutate and notify
        myData().childProp = 456;
        myData.valueHasMutated();
        expect(testNode.childNodes[0].innerHTML).toEqual("result = 456");
    });

    it('Should stop tracking inner observables immediately when the container node is removed from the document', function() {
        var innerObservable = ko.observable("some value");
        ko.setTemplateEngine(new dummyTemplateEngine({ someTemplate: "result = [js: childProp()]" }));
        testNode.innerHTML = "<div data-bind='template: { name: \"someTemplate\", data: someProp }'></div>";
        ko.applyBindings({ someProp: { childProp: innerObservable} }, testNode);

        expect(innerObservable.getSubscriptionsCount()).toEqual(1);
        ko.removeNode(testNode.childNodes[0]);
        expect(innerObservable.getSubscriptionsCount()).toEqual(0);
    });

    it('Should be able to pick template via an observable model property', function () {
        ko.setTemplateEngine(new dummyTemplateEngine({
            firstTemplate: "First template output",
            secondTemplate: "Second template output"
        }));

        var chosenTemplate = ko.observable("firstTemplate");
        testNode.innerHTML = "<div data-bind='template: chosenTemplate'></div>";
        ko.applyBindings({ chosenTemplate: chosenTemplate }, testNode);
        expect(testNode.childNodes[0].innerHTML).toEqual("First template output");

        chosenTemplate("secondTemplate");
        expect(testNode.childNodes[0].innerHTML).toEqual("Second template output");
    });

    it('Should be able to pick template via an observable model property when specified as "name"', function () {
        ko.setTemplateEngine(new dummyTemplateEngine({
            firstTemplate: "First template output",
            secondTemplate: "Second template output"
        }));

        var chosenTemplate = ko.observable("firstTemplate");
        testNode.innerHTML = "<div data-bind='template: { name: chosenTemplate }'></div>";
        ko.applyBindings({ chosenTemplate: chosenTemplate }, testNode);
        expect(testNode.childNodes[0].innerHTML).toEqual("First template output");

        chosenTemplate("secondTemplate");
        expect(testNode.childNodes[0].innerHTML).toEqual("Second template output");
    });

    it('Should be able to pick template via an observable model property when specified as "name" in conjunction with "foreach"', function () {
        ko.setTemplateEngine(new dummyTemplateEngine({
            firstTemplate: "First",
            secondTemplate: "Second"
        }));

        var chosenTemplate = ko.observable("firstTemplate");
        testNode.innerHTML = "<div data-bind='template: { name: chosenTemplate, foreach: [1,2,3] }'></div>";
        ko.applyBindings({ chosenTemplate: chosenTemplate }, testNode);
        expect(testNode.childNodes[0].innerHTML).toEqual("FirstFirstFirst");

        chosenTemplate("secondTemplate");
        expect(testNode.childNodes[0].innerHTML).toEqual("SecondSecondSecond");
    });

    it('Should be able to pick template as a function of the data item using data-bind syntax, with the binding context available as a second parameter', function () {
        var templatePicker = function(dataItem, bindingContext) {
            // Having the entire binding context available means you can read sibling or parent level properties
            expect(bindingContext.$parent.anotherProperty).toEqual(456);
            return dataItem.myTemplate;
        };
        ko.setTemplateEngine(new dummyTemplateEngine({ someTemplate: "result = [js: childProp]" }));
        testNode.innerHTML = "<div data-bind='template: { name: templateSelectorFunction, data: someProp }'></div>";
        ko.applyBindings({ someProp: { childProp: 123, myTemplate: "someTemplate" }, templateSelectorFunction: templatePicker, anotherProperty: 456 }, testNode);
        expect(testNode.childNodes[0].innerHTML).toEqual("result = 123");
    });

    it('Should be able to chain templates, rendering one from inside another', function () {
        ko.setTemplateEngine(new dummyTemplateEngine({
            outerTemplate: "outer template output, [renderTemplate:innerTemplate]", // [renderTemplate:...] is special syntax supported by dummy template engine
            innerTemplate: "inner template output <span data-bind='text: 123'></span>"
        }));
        testNode.innerHTML = "<div data-bind='template:\"outerTemplate\"'></div>";
        ko.applyBindings(null, testNode);
        expect(testNode.childNodes[0]).toContainHtml("outer template output, inner template output <span>123</span>");
    });

    it('Should rerender chained templates when their dependencies change, without rerendering parent templates', function () {
        var observable = new ko.observable("ABC");
        var timesRenderedOuter = 0, timesRenderedInner = 0;
        ko.setTemplateEngine(new dummyTemplateEngine({
            outerTemplate: function () { timesRenderedOuter++; return "outer template output, [renderTemplate:innerTemplate]" }, // [renderTemplate:...] is special syntax supported by dummy template engine
            innerTemplate: function () { timesRenderedInner++; return observable() }
        }));
        testNode.innerHTML = "<div data-bind='template:\"outerTemplate\"'></div>";
        ko.applyBindings(null, testNode);
        expect(testNode.childNodes[0]).toContainHtml("outer template output, abc");
        expect(timesRenderedOuter).toEqual(1);
        expect(timesRenderedInner).toEqual(1);

        observable("DEF");
        expect(testNode.childNodes[0]).toContainHtml("outer template output, def");
        expect(timesRenderedOuter).toEqual(1);
        expect(timesRenderedInner).toEqual(2);
    });

    it('Should stop tracking inner observables referenced by a chained template as soon as the chained template output node is removed from the document', function() {
        var innerObservable = ko.observable("some value");
        ko.setTemplateEngine(new dummyTemplateEngine({
            outerTemplate: "outer template output, <span id='innerTemplateOutput'>[renderTemplate:innerTemplate]</span>",
            innerTemplate: "result = [js: childProp()]"
        }));
        testNode.innerHTML = "<div data-bind='template: { name: \"outerTemplate\", data: someProp }'></div>";
        ko.applyBindings({ someProp: { childProp: innerObservable} }, testNode);

        expect(innerObservable.getSubscriptionsCount()).toEqual(1);
        ko.removeNode(document.getElementById('innerTemplateOutput'));
        expect(innerObservable.getSubscriptionsCount()).toEqual(0);
    });

    it('Should handle data-bind attributes from inside templates, regardless of element and attribute casing', function () {
        ko.setTemplateEngine(new dummyTemplateEngine({ someTemplate: "<INPUT Data-Bind='value:\"Hi\"' />" }));
        ko.renderTemplate("someTemplate", null, null, testNode);
        expect(testNode.childNodes[0].value).toEqual("Hi");
    });

    it('Should handle data-bind attributes that include newlines from inside templates', function () {
        ko.setTemplateEngine(new dummyTemplateEngine({ someTemplate: "<input data-bind='value:\n\"Hi\"' />" }));
        ko.renderTemplate("someTemplate", null, null, testNode);
        expect(testNode.childNodes[0].value).toEqual("Hi");
    });

    it('Data binding syntax should be able to reference variables put into scope by the template engine', function () {
        ko.setTemplateEngine(new dummyTemplateEngine({ someTemplate: "<input data-bind='value:message' />" }));
        ko.renderTemplate("someTemplate", null, { templateRenderingVariablesInScope: { message: "hello"} }, testNode);
        expect(testNode.childNodes[0].value).toEqual("hello");
    });

    it('Should handle data-bind attributes with spaces around equals sign from inside templates and reference variables', function () {
        ko.setTemplateEngine(new dummyTemplateEngine({ someTemplate: "<input data-bind = 'value:message' />" }));
        ko.renderTemplate("someTemplate", null, { templateRenderingVariablesInScope: { message: "hello"} }, testNode);
        expect(testNode.childNodes[0].value).toEqual("hello");
    });

    it('Data binding syntax should be able to use $element in binding value', function() {
        ko.setTemplateEngine(new dummyTemplateEngine({ someTemplate: "<div data-bind='text: $element.tagName'></div>" }));
        ko.renderTemplate("someTemplate", null, null, testNode);
        expect(testNode.childNodes[0]).toContainText("DIV");
    });

    it('Data binding syntax should be able to use $context in binding value to refer to the context object', function() {
        ko.setTemplateEngine(new dummyTemplateEngine({ someTemplate: "<div data-bind='text: $context.$data === $data'></div>" }));
        ko.renderTemplate("someTemplate", {}, null, testNode);
        expect(testNode.childNodes[0]).toContainText("true");
    });

    it('Data binding syntax should be able to use $rawData in binding value to refer to a top level template\'s view model observable', function() {
        var data = ko.observable('value');
        ko.setTemplateEngine(new dummyTemplateEngine({ someTemplate: "<div data-bind='text: ko.isObservable($rawData)'></div>" }));
        ko.renderTemplate("someTemplate", data, null, testNode);
        expect(testNode.childNodes[0]).toContainText("true");
        expect(data.getSubscriptionsCount('change')).toEqual(1);    // only subscription is from the templating code
    });

    it('Data binding syntax should be able to use $rawData in binding value to refer to a data-bound template\'s view model observable', function() {
        ko.setTemplateEngine(new dummyTemplateEngine({ someTemplate: "<div data-bind='text: ko.isObservable($rawData)'></div>" }));
        testNode.innerHTML = "<div data-bind='template: { name: \"someTemplate\", data: someProp }'></div>";

        var viewModel = { someProp: ko.observable('value') };
        ko.applyBindings(viewModel, testNode);

        expect(testNode.childNodes[0].childNodes[0]).toContainText("true");
        expect(viewModel.someProp.getSubscriptionsCount('change')).toEqual(1);    // only subscription is from the templating code
    });

    it('Data binding syntax should defer evaluation of variables until the end of template rendering (so bindings can take independent subscriptions to them)', function () {
        ko.setTemplateEngine(new dummyTemplateEngine({
            someTemplate: "<input data-bind='value:message' />[js: message = 'goodbye'; undefined; ]"
        }));
        ko.renderTemplate("someTemplate", null, { templateRenderingVariablesInScope: { message: "hello"} }, testNode);
        expect(testNode.childNodes[0].value).toEqual("goodbye");
    });

    it('Data binding syntax should use the template\'s \'data\' object as the viewModel value (so \'this\' is set correctly when calling click handlers etc.)', function() {
        ko.setTemplateEngine(new dummyTemplateEngine({
            someTemplate: "<button data-bind='click: someFunctionOnModel'>click me</button>"
        }));
        var viewModel = {
            didCallMyFunction : false,
            someFunctionOnModel : function() { this.didCallMyFunction = true }
        };
        ko.renderTemplate("someTemplate", viewModel, null, testNode);
        var buttonNode = testNode.childNodes[0];
        expect(buttonNode.tagName).toEqual("BUTTON"); // Be sure we're clicking the right thing
        buttonNode.click();
        expect(viewModel.didCallMyFunction).toEqual(true);
    });

    it('Data binding syntax should permit nested templates, and only bind inner templates once when using getBindingAccessors', function() {
        this.restoreAfter(ko.bindingProvider, 'instance');

        // Will verify that bindings are applied only once for both inline (rewritten) bindings,
        // and external (non-rewritten) ones
        var originalBindingProvider = ko.bindingProvider.instance;
        ko.bindingProvider.instance = {
            nodeHasBindings: function(node, bindingContext) {
                return (node.tagName == 'EM') || originalBindingProvider.nodeHasBindings(node, bindingContext);
            },
            getBindingAccessors: function(node, bindingContext) {
                if (node.tagName == 'EM') {
                    return {
                        text: function() {
                            return ++model.numExternalBindings;
                        }
                    };
                }
                return originalBindingProvider.getBindingAccessors(node, bindingContext);
            }
        };

        ko.setTemplateEngine(new dummyTemplateEngine({
            outerTemplate: "Outer <div data-bind='template: { name: \"innerTemplate\", bypassDomNodeWrap: true }'></div>",
            innerTemplate: "Inner via inline binding: <span data-bind='text: ++numRewrittenBindings'></span>"
                         + "Inner via external binding: <em></em>"
        }));
        var model = { numRewrittenBindings: 0, numExternalBindings: 0 };
        testNode.innerHTML = "<div data-bind='template: { name: \"outerTemplate\", bypassDomNodeWrap: true }'></div>";
        ko.applyBindings(model, testNode);
        expect(model.numRewrittenBindings).toEqual(1);
        expect(model.numExternalBindings).toEqual(1);
        expect(testNode.childNodes[0]).toContainHtml("outer <div>inner via inline binding: <span>1</span>inner via external binding: <em>1</em></div>");
    });

    it('Data binding syntax should permit nested templates, and only bind inner templates once when using getBindings', function() {
        this.restoreAfter(ko.bindingProvider, 'instance');

        // Will verify that bindings are applied only once for both inline (rewritten) bindings,
        // and external (non-rewritten) ones. Because getBindings actually gets called twice, we need
        // to expect two calls (but still it's a single binding).
        var originalBindingProvider = ko.bindingProvider.instance;
        ko.bindingProvider.instance = {
            nodeHasBindings: function(node, bindingContext) {
                return (node.tagName == 'EM') || originalBindingProvider.nodeHasBindings(node, bindingContext);
            },
            getBindings: function(node, bindingContext) {
                if (node.tagName == 'EM')
                    return { text: ++model.numExternalBindings };
                return originalBindingProvider.getBindings(node, bindingContext);
            }
        };

        ko.setTemplateEngine(new dummyTemplateEngine({
            outerTemplate: "Outer <div data-bind='template: { name: \"innerTemplate\", bypassDomNodeWrap: true }'></div>",
            innerTemplate: "Inner via inline binding: <span data-bind='text: ++numRewrittenBindings'></span>"
                         + "Inner via external binding: <em></em>"
        }));
        var model = { numRewrittenBindings: 0, numExternalBindings: 0 };
        testNode.innerHTML = "<div data-bind='template: { name: \"outerTemplate\", bypassDomNodeWrap: true }'></div>";
        ko.applyBindings(model, testNode);
        expect(model.numRewrittenBindings).toEqual(1);
        expect(model.numExternalBindings).toEqual(2);
        expect(testNode.childNodes[0]).toContainHtml("outer <div>inner via inline binding: <span>1</span>inner via external binding: <em>2</em></div>");
    });

    it('Should accept a "nodes" option that gives the template nodes', function() {
        // This is an alternative to specifying a named template, and is useful in conjunction with components
        ko.setTemplateEngine(new dummyTemplateEngine({
            innerTemplate: "the name is [js: name()]" // See that custom template engines are applied to the injected nodes
        }));

        testNode.innerHTML = "<div data-bind='template: { nodes: testNodes, data: testData, bypassDomNodeWrap: true }'></div>";
        var model = {
            testNodes: [
                document.createTextNode("begin"),
                document.createElement("span"),
                document.createTextNode("end")
            ],
            testData: { name: ko.observable("alpha") }
        };
        model.testNodes[1].setAttribute("data-bind", "template: 'innerTemplate'"); // See that bindings are applied to the injected nodes

        ko.applyBindings(model, testNode);
        expect(testNode.childNodes[0]).toContainHtml("begin<span>the name is alpha</span>end");

        // The injected bindings update to match model changes as usual
        model.testData.name("beta");
        expect(testNode.childNodes[0]).toContainHtml("begin<span>the name is beta</span>end");
    });

    it('Should accept a "nodes" option that gives the template nodes, and it can be used in conjunction with "foreach"', function() {
        testNode.innerHTML = "<div data-bind='template: { nodes: testNodes, foreach: testData, bypassDomNodeWrap: true }'></div>";

        // This time we'll check that the nodes array doesn't have to be a real array - it can be the .childNodes
        // property of a DOM element, which is subtly different.
        var templateContainer = document.createElement("div");
        templateContainer.innerHTML = "[<span data-bind='text: name'></span>]";
        var model = {
            testNodes: templateContainer.childNodes,
            testData: ko.observableArray([{ name: ko.observable("alpha") }, { name: "beta" }, { name: "gamma" }])
        };
        model.testNodes[1].setAttribute("data-bind", "text: name");

        ko.applyBindings(model, testNode);
        expect(testNode.childNodes[0]).toContainText("[alpha][beta][gamma]");

        // The injected bindings update to match model changes as usual
        model.testData.splice(1, 1);
        expect(testNode.childNodes[0]).toContainText("[alpha][gamma]");

        // Changing the nodes array does *not* affect subsequent output from the template.
        // This behavior may be subject to change. I'm adding this assertion just to record what
        // the current behavior is, even if we might want to alter it in the future. We don't need
        // to document or make any guarantees about what happens if you do this - it's just not
        // a supported thing to do.
        templateContainer.innerHTML = "[Modified, but will not appear in template output because the nodes were already cloned]";
        model.testData.splice(1, 0, { name: "delta" });
        expect(testNode.childNodes[0]).toContainText("[alpha][delta][gamma]");
    });

    it('Should interpret "nodes: anyFalseyValue" as being equivalent to supplying an empty node array', function() {
        // This behavior helps to avoid inconsistency if you're programmatically supplying a node array
        // but sometimes you might not have any nodes - you don't want the template binding to dynamically
        // switch over to "inline template" mode just because your 'nodes' value is null, for example.
        testNode.innerHTML = "<div data-bind='template: { nodes: null, bypassDomNodeWrap: true }'>Should not use this inline template</div>";
        ko.applyBindings(null, testNode);
        expect(testNode.childNodes[0]).toContainHtml('');
    });

    it('Should not allow "nodes: someObservableArray"', function() {
        // See comment in implementation for reasoning
        testNode.innerHTML = "<div data-bind='template: { nodes: myNodes, bypassDomNodeWrap: true }'>Should not use this inline template</div>";
        expect(function() {
            ko.applyBindings({ myNodes: ko.observableArray() }, testNode);
        }).toThrowContaining("The \"nodes\" option must be a plain, non-observable array");
    });

    describe('Data binding \'foreach\' option', function() {
        it('Should remove existing content', function () {
            ko.setTemplateEngine(new dummyTemplateEngine({ itemTemplate: "<span>template content</span>" }));
            testNode.innerHTML = "<div data-bind='template: { name: \"itemTemplate\", foreach: myCollection }'><span>existing content</span></div>";

            ko.applyBindings({ myCollection: [ {} ] }, testNode);
            expect(testNode.childNodes[0]).toContainHtml("<span>template content</span>");
        });

        it('Should render for each item in an array but doesn\'t rerender everything if you push or splice', function () {
            var myArray = new ko.observableArray([{ personName: "Bob" }, { personName: "Frank"}]);
            ko.setTemplateEngine(new dummyTemplateEngine({ itemTemplate: "<div>The item is [js: personName]</div>" }));
            testNode.innerHTML = "<div data-bind='template: { name: \"itemTemplate\", foreach: myCollection }'></div>";

            ko.applyBindings({ myCollection: myArray }, testNode);
            expect(testNode.childNodes[0]).toContainHtml("<div>the item is bob</div><div>the item is frank</div>");
            var originalBobNode = testNode.childNodes[0].childNodes[0];
            var originalFrankNode = testNode.childNodes[0].childNodes[1];

            myArray.push({ personName: "Steve" });
            expect(testNode.childNodes[0]).toContainHtml("<div>the item is bob</div><div>the item is frank</div><div>the item is steve</div>");
            expect(testNode.childNodes[0].childNodes[0]).toEqual(originalBobNode);
            expect(testNode.childNodes[0].childNodes[1]).toEqual(originalFrankNode);
        });

        it('Should apply bindings within the context of each item in the array', function () {
            var myArray = new ko.observableArray([{ personName: "Bob" }, { personName: "Frank"}]);
            ko.setTemplateEngine(new dummyTemplateEngine({ itemTemplate: "The item is <span data-bind='text: personName'></span>" }));
            testNode.innerHTML = "<div data-bind='template: { name: \"itemTemplate\", foreach: myCollection }'></div>";

            ko.applyBindings({ myCollection: myArray }, testNode);
            expect(testNode.childNodes[0]).toContainHtml("the item is <span>bob</span>the item is <span>frank</span>");
        });

        it('Should only bind each group of output nodes once', function() {
            var initCalls = 0;
            ko.bindingHandlers.countInits = { init: function() { initCalls++ } };
            ko.setTemplateEngine(new dummyTemplateEngine({ itemTemplate: "<span data-bind='countInits: true'></span>" }));
            testNode.innerHTML = "<div data-bind='template: { name: \"itemTemplate\", foreach: myCollection }'></div>";

            ko.applyBindings({ myCollection: [1,2,3] }, testNode);
            expect(initCalls).toEqual(3); // 3 because there were 3 items in myCollection
        });

        it('Should handle templates in which the very first node has a binding', function() {
            // Represents https://github.com/SteveSanderson/knockout/pull/440
            // Previously, the rewriting (which introduces a comment node before the bound node) was interfering
            // with the array-to-DOM-node mapping state tracking
            ko.setTemplateEngine(new dummyTemplateEngine({ mytemplate: "<div data-bind='text: $data'></div>" }));
            testNode.innerHTML = "<div data-bind=\"template: { name: 'mytemplate', foreach: items }\"></div>";

            // Bind against initial array containing one entry. UI just shows "original"
            var myArray = ko.observableArray(["original"]);
            ko.applyBindings({ items: myArray }, testNode);
            expect(testNode.childNodes[0]).toContainHtml("<div>original</div>");

            // Now replace the entire array contents with one different entry.
            // UI just shows "new" (previously with bug, showed "original" AND "new")
            myArray(["new"]);
            expect(testNode.childNodes[0]).toContainHtml("<div>new</div>");
        });

        it('Should handle chained templates in which the very first node has a binding', function() {
            // See https://github.com/SteveSanderson/knockout/pull/440 and https://github.com/SteveSanderson/knockout/pull/144
            ko.setTemplateEngine(new dummyTemplateEngine({
                outerTemplate: "<div data-bind='text: $data'></div>[renderTemplate:innerTemplate]x", // [renderTemplate:...] is special syntax supported by dummy template engine
                innerTemplate: "inner <span data-bind='text: 123'></span>"
            }));
            testNode.innerHTML = "<div data-bind=\"template: { name: 'outerTemplate', foreach: items }\"></div>";

            // Bind against initial array containing one entry.
            var myArray = ko.observableArray(["original"]);
            ko.applyBindings({ items: myArray }, testNode);
            expect(testNode.childNodes[0]).toContainHtml("<div>original</div>inner <span>123</span>x");

            // Now replace the entire array contents with one different entry.
            myArray(["new"]);
            expect(testNode.childNodes[0]).toContainHtml("<div>new</div>inner <span>123</span>x");
        });

        it('Should handle templates in which the very first node has a binding but it does not reference any observables', function() {
            // Represents https://github.com/SteveSanderson/knockout/issues/739
            // Previously, the rewriting (which introduces a comment node before the bound node) was interfering
            // with the array-to-DOM-node mapping state tracking
            ko.setTemplateEngine(new dummyTemplateEngine({ mytemplate: "<div data-bind='attr: {}'>[js:name()]</div>" }));
            testNode.innerHTML = "<div data-bind=\"template: { name: 'mytemplate', foreach: items }\"></div>";

            // Bind against array, referencing an observable property
            var myItem = { name: ko.observable("a") };
            ko.applyBindings({ items: [myItem] }, testNode);
            expect(testNode.childNodes[0]).toContainHtml("<div>a</div>");

            // Modify the observable property and check that UI is updated
            // Previously with the bug, it wasn't updated because the removal of the memo comment caused the array-to-DOM-node computed to be disposed
            myItem.name("b");
            expect(testNode.childNodes[0]).toContainHtml("<div>b</div>");
        });

        it('Should apply bindings with an $index in the context', function () {
            var myArray = new ko.observableArray([{ personName: "Bob" }, { personName: "Frank"}]);
            ko.setTemplateEngine(new dummyTemplateEngine({ itemTemplate: "The item # is <span data-bind='text: $index'></span>" }));
            testNode.innerHTML = "<div data-bind='template: { name: \"itemTemplate\", foreach: myCollection }'></div>";

            ko.applyBindings({ myCollection: myArray }, testNode);
            expect(testNode.childNodes[0]).toContainHtml("the item # is <span>0</span>the item # is <span>1</span>");
        });

        it('Should update bindings that reference an $index if the list changes', function () {
            var myArray = new ko.observableArray([{ personName: "Bob" }, { personName: "Frank"}]);
            ko.setTemplateEngine(new dummyTemplateEngine({ itemTemplate: "The item <span data-bind='text: personName'></span>is <span data-bind='text: $index'></span>" }));
            testNode.innerHTML = "<div data-bind='template: { name: \"itemTemplate\", foreach: myCollection }'></div>";

            ko.applyBindings({ myCollection: myArray }, testNode);
            expect(testNode.childNodes[0]).toContainHtml("the item <span>bob</span>is <span>0</span>the item <span>frank</span>is <span>1</span>");

            var frank = myArray.pop(); // remove frank
            expect(testNode.childNodes[0]).toContainHtml("the item <span>bob</span>is <span>0</span>");

            myArray.unshift(frank); // put frank in the front
            expect(testNode.childNodes[0]).toContainHtml("the item <span>frank</span>is <span>0</span>the item <span>bob</span>is <span>1</span>");
        });

        it('Should accept array with "undefined" and "null" items', function () {
            var myArray = new ko.observableArray([undefined, null]);
            ko.setTemplateEngine(new dummyTemplateEngine({ itemTemplate: "The item is <span data-bind='text: String($data)'></span>" }));
            testNode.innerHTML = "<div data-bind='template: { name: \"itemTemplate\", foreach: myCollection }'></div>";

            ko.applyBindings({ myCollection: myArray }, testNode);
            expect(testNode.childNodes[0]).toContainHtml("the item is <span>undefined</span>the item is <span>null</span>");
        });

        it('Should update DOM nodes when a dependency of their mapping function changes', function() {
            var myObservable = new ko.observable("Steve");
            var myArray = new ko.observableArray([{ personName: "Bob" }, { personName: myObservable }, { personName: "Another" }]);
            ko.setTemplateEngine(new dummyTemplateEngine({ itemTemplate: "<div>The item is [js: ko.utils.unwrapObservable(personName)]</div>" }));
            testNode.innerHTML = "<div data-bind='template: { name: \"itemTemplate\", foreach: myCollection }'></div>";

            ko.applyBindings({ myCollection: myArray }, testNode);
            expect(testNode.childNodes[0]).toContainHtml("<div>the item is bob</div><div>the item is steve</div><div>the item is another</div>");
            var originalBobNode = testNode.childNodes[0].childNodes[0];

            myObservable("Steve2");
            expect(testNode.childNodes[0]).toContainHtml("<div>the item is bob</div><div>the item is steve2</div><div>the item is another</div>");
            expect(testNode.childNodes[0].childNodes[0]).toEqual(originalBobNode);

            // Ensure we can still remove the corresponding nodes (even though they've changed), and that doing so causes the subscription to be disposed
            expect(myObservable.getSubscriptionsCount()).toEqual(1);
            myArray.splice(1, 1);
            expect(testNode.childNodes[0]).toContainHtml("<div>the item is bob</div><div>the item is another</div>");
            myObservable("Something else"); // Re-evaluating the observable causes the orphaned subscriptions to be disposed
            expect(myObservable.getSubscriptionsCount()).toEqual(0);
        });

        it('Should treat a null parameter as meaning \'no items\'', function() {
            var myArray = new ko.observableArray(["A", "B"]);
            ko.setTemplateEngine(new dummyTemplateEngine({ itemTemplate: "hello" }));
            testNode.innerHTML = "<div data-bind='template: { name: \"itemTemplate\", foreach: myCollection }'></div>";

            ko.applyBindings({ myCollection: myArray }, testNode);
            expect(testNode.childNodes[0].childNodes.length).toEqual(2);

            // Now set the observable to null and check it's treated like an empty array
            // (because how else should null be interpreted?)
            myArray(null);
            expect(testNode.childNodes[0].childNodes.length).toEqual(0);
        });

        it('Should accept an \"as\" option to define an alias for the iteration variable', function() {
            // Note: There are more detailed specs (e.g., covering nesting) associated with the "foreach" binding which
            // uses this templating functionality internally.
            var myArray = new ko.observableArray(["A", "B"]);
            ko.setTemplateEngine(new dummyTemplateEngine({ itemTemplate: "[js:myAliasedItem]" }));
            testNode.innerHTML = "<div data-bind='template: { name: \"itemTemplate\", foreach: myCollection, as: \"myAliasedItem\" }'></div>";

            ko.applyBindings({ myCollection: myArray }, testNode);
            expect(testNode.childNodes[0]).toContainText("AB");
        });

        it('Should stop tracking inner observables when the container node is removed', function() {
            var innerObservable = ko.observable("some value");
            var myArray = new ko.observableArray([{obsVal:innerObservable}, {obsVal:innerObservable}]);
            ko.setTemplateEngine(new dummyTemplateEngine({ itemTemplate: "The item is [js: ko.utils.unwrapObservable(obsVal)]" }));
            testNode.innerHTML = "<div data-bind='template: { name: \"itemTemplate\", foreach: myCollection }'></div>";

            ko.applyBindings({ myCollection: myArray }, testNode);
            expect(innerObservable.getSubscriptionsCount()).toEqual(2);

            ko.removeNode(testNode.childNodes[0]);
            expect(innerObservable.getSubscriptionsCount()).toEqual(0);
        });

        it('Should stop tracking inner observables related to each array item when that array item is removed', function() {
            var innerObservable = ko.observable("some value");
            var myArray = new ko.observableArray([{obsVal:innerObservable}, {obsVal:innerObservable}]);
            ko.setTemplateEngine(new dummyTemplateEngine({ itemTemplate: "The item is [js: ko.utils.unwrapObservable(obsVal)]" }));
            testNode.innerHTML = "<div data-bind='template: { name: \"itemTemplate\", foreach: myCollection }'></div>";

            ko.applyBindings({ myCollection: myArray }, testNode);
            expect(innerObservable.getSubscriptionsCount()).toEqual(2);

            myArray.splice(1, 1);
            expect(innerObservable.getSubscriptionsCount()).toEqual(1);
            myArray([]);
            expect(innerObservable.getSubscriptionsCount()).toEqual(0);
        });

        it('Should omit any items whose \'_destroy\' flag is set (unwrapping the flag if it is observable)', function() {
            var myArray = new ko.observableArray([{ someProp: 1 }, { someProp: 2, _destroy: 'evals to true' }, { someProp : 3 }, { someProp: 4, _destroy: ko.observable(false) }]);
            ko.setTemplateEngine(new dummyTemplateEngine({ itemTemplate: "<div>someProp=[js: someProp]</div>" }));
            testNode.innerHTML = "<div data-bind='template: { name: \"itemTemplate\", foreach: myCollection }'></div>";

            ko.applyBindings({ myCollection: myArray }, testNode);
            expect(testNode.childNodes[0]).toContainHtml("<div>someprop=1</div><div>someprop=3</div><div>someprop=4</div>");
        });

        it('Should include any items whose \'_destroy\' flag is set if you use includeDestroyed', function() {
            var myArray = new ko.observableArray([{ someProp: 1 }, { someProp: 2, _destroy: 'evals to true' }, { someProp : 3 }]);
            ko.setTemplateEngine(new dummyTemplateEngine({ itemTemplate: "<div>someProp=[js: someProp]</div>" }));
            testNode.innerHTML = "<div data-bind='template: { name: \"itemTemplate\", foreach: myCollection, includeDestroyed: true }'></div>";

            ko.applyBindings({ myCollection: myArray }, testNode);
            expect(testNode.childNodes[0]).toContainHtml("<div>someprop=1</div><div>someprop=2</div><div>someprop=3</div>");
        });

        it('Should be able to render a different template for each array entry by passing a function as template name, with the array entry\'s binding context available as a second parameter', function() {
            var myArray = new ko.observableArray([
                { preferredTemplate: 1, someProperty: 'firstItemValue' },
                { preferredTemplate: 2, someProperty: 'secondItemValue' }
            ]);
            ko.setTemplateEngine(new dummyTemplateEngine({
                firstTemplate: "<div>Template1Output, [js:someProperty]</div>",
                secondTemplate: "<div>Template2Output, [js:someProperty]</div>"
            }));
            testNode.innerHTML = "<div data-bind='template: {name: getTemplateModelProperty, foreach: myCollection}'></div>";

            var getTemplate = function(dataItem, bindingContext) {
                // Having the item's binding context available means you can read sibling or parent level properties
                expect(bindingContext.$parent.anotherProperty).toEqual(123);

                return dataItem.preferredTemplate == 1 ? 'firstTemplate' : 'secondTemplate';
            };
            ko.applyBindings({ myCollection: myArray, getTemplateModelProperty: getTemplate, anotherProperty: 123 }, testNode);
            expect(testNode.childNodes[0]).toContainHtml("<div>template1output, firstitemvalue</div><div>template2output, seconditemvalue</div>");
        });

        it('Should update all child contexts and bindings when used with a top-level observable view model', function() {
            var myVm = ko.observable({items: ['A', 'B', 'C'], itemValues: { 'A': [1, 2, 3], 'B': [4, 5, 6], 'C': [7, 8, 9] }});
            var engine = new dummyTemplateEngine({
                itemTemplate: "<span>The <span data-bind='text: $index'>&nbsp;</span> item <span data-bind='text: $data'>&nbsp;</span> has <span data-bind='template: { name: \"valueTemplate\", foreach: $root.itemValues[$data] }'>&nbsp;</span> </span>",
                valueTemplate: "<span data-bind='text: $index'>&nbsp;</span>.<span data-bind='text: $data'>&nbsp;</span>,"
            });
            engine.createJavaScriptEvaluatorBlock = function (script) { return "[[js:" + script + "]]"; };  // because we're using a binding with brackets
            ko.setTemplateEngine(engine);

            testNode.innerHTML = "<div data-bind='template: { name: \"itemTemplate\", foreach: items }'></div>";

            ko.applyBindings(myVm, testNode);
            expect(testNode.childNodes[0]).toContainText("The 0 item A has 0.1,1.2,2.3, The 1 item B has 0.4,1.5,2.6, The 2 item C has 0.7,1.8,2.9, ");

            myVm({items: ['C', 'B', 'A'], itemValues: { 'A': [1, 2, 30], 'B': [4, 5, 60], 'C': [7, 8, 90] }});
            expect(testNode.childNodes[0]).toContainText("The 0 item C has 0.7,1.8,2.90, The 1 item B has 0.4,1.5,2.60, The 2 item A has 0.1,1.2,2.30, ");
        });

    });

    it('Data binding syntax should support \"if\" condition', function() {
        ko.setTemplateEngine(new dummyTemplateEngine({ myTemplate: "Value: [js: myProp().childProp]" }));
        testNode.innerHTML = "<div data-bind='template: { name: \"myTemplate\", \"if\": myProp }'></div>";

        var viewModel = { myProp: ko.observable({ childProp: 'abc' }) };
        ko.applyBindings(viewModel, testNode);

        // Initially there is a value
        expect(testNode.childNodes[0]).toContainText("Value: abc");

        // Causing the condition to become false causes the output to be removed
        viewModel.myProp(null);
        expect(testNode.childNodes[0]).toContainText("");

        // Causing the condition to become true causes the output to reappear
        viewModel.myProp({ childProp: 'def' });
        expect(testNode.childNodes[0]).toContainText("Value: def");
    });

    it('Data binding syntax should support \"ifnot\" condition', function() {
        ko.setTemplateEngine(new dummyTemplateEngine({ myTemplate: "Hello" }));
        testNode.innerHTML = "<div data-bind='template: { name: \"myTemplate\", ifnot: shouldHide }'></div>";

        var viewModel = { shouldHide: ko.observable(true) };
        ko.applyBindings(viewModel, testNode);

        // Initially there is no output (shouldHide=true)
        expect(testNode.childNodes[0]).toContainText("");

        // Causing the condition to become false causes the output to be displayed
        viewModel.shouldHide(false);
        expect(testNode.childNodes[0]).toContainText("Hello");

        // Causing the condition to become true causes the output to disappear
        viewModel.shouldHide(true);
        expect(testNode.childNodes[0]).toContainText("");
    });

    it('Data binding syntax should support \"if\" condition in conjunction with foreach', function() {
        ko.setTemplateEngine(new dummyTemplateEngine({ myTemplate: "Value: [js: myProp().childProp]" }));
        testNode.innerHTML = "<div data-bind='template: { name: \"myTemplate\", \"if\": myProp, foreach: [$data, $data, $data] }'></div>";

        var viewModel = { myProp: ko.observable({ childProp: 'abc' }) };
        ko.applyBindings(viewModel, testNode);
        expect(testNode.childNodes[0].childNodes[0].nodeValue).toEqual("Value: abc");
        expect(testNode.childNodes[0].childNodes[1].nodeValue).toEqual("Value: abc");
        expect(testNode.childNodes[0].childNodes[2].nodeValue).toEqual("Value: abc");

        // Causing the condition to become false causes the output to be removed
        viewModel.myProp(null);
        expect(testNode.childNodes[0]).toContainText("");

        // Causing the condition to become true causes the output to reappear
        viewModel.myProp({ childProp: 'def' });
        expect(testNode.childNodes[0].childNodes[0].nodeValue).toEqual("Value: def");
        expect(testNode.childNodes[0].childNodes[1].nodeValue).toEqual("Value: def");
        expect(testNode.childNodes[0].childNodes[2].nodeValue).toEqual("Value: def");
    });

    it('Should be able to populate checkboxes from inside templates, despite IE6 limitations', function () {
        ko.setTemplateEngine(new dummyTemplateEngine({ someTemplate: "<input type='checkbox' data-bind='checked:isChecked' />" }));
        ko.renderTemplate("someTemplate", null, { templateRenderingVariablesInScope: { isChecked: true } }, testNode);
        expect(testNode.childNodes[0].checked).toEqual(true);
    });

    it('Should be able to populate radio buttons from inside templates, despite IE6 limitations', function () {
        ko.setTemplateEngine(new dummyTemplateEngine({ someTemplate: "<input type='radio' name='somename' value='abc' data-bind='checked:someValue' />" }));
        ko.renderTemplate("someTemplate", null, { templateRenderingVariablesInScope: { someValue: 'abc' } }, testNode);
        expect(testNode.childNodes[0].checked).toEqual(true);
    });

    it('Data binding \'templateOptions\' should be passed to template', function() {
        var myModel = {
            someAdditionalData: { myAdditionalProp: "someAdditionalValue" },
            people: new ko.observableArray([
                { name: "Alpha" },
                { name: "Beta" }
            ])
        };
        ko.setTemplateEngine(new dummyTemplateEngine({myTemplate: "<div>Person [js:name] has additional property [js:templateOptions.myAdditionalProp]</div>"}));
        testNode.innerHTML = "<div data-bind='template: {name: \"myTemplate\", foreach: people, templateOptions: someAdditionalData }'></div>";

        ko.applyBindings(myModel, testNode);
        expect(testNode.childNodes[0]).toContainHtml("<div>person alpha has additional property someadditionalvalue</div><div>person beta has additional property someadditionalvalue</div>");
    });

    it('If the template binding is updated, should dispose any template subscriptions previously associated with the element', function() {
        var myObservable = ko.observable("some value"),
            myModel = {
                subModel: ko.observable({ myObservable: myObservable })
            };
        ko.setTemplateEngine(new dummyTemplateEngine({myTemplate: "<span>The value is [js:myObservable()]</span>"}));
        testNode.innerHTML = "<div data-bind='template: {name: \"myTemplate\", data: subModel}'></div>";
        ko.applyBindings(myModel, testNode);

        // Right now the template references myObservable, so there should be exactly one subscription on it
        expect(testNode.childNodes[0]).toContainText("The value is some value");
        expect(myObservable.getSubscriptionsCount()).toEqual(1);
        var renderedNode1 = testNode.childNodes[0].childNodes[0];

        // By changing the object for subModel, we force the data-bind value to be re-evaluated and the template to be re-rendered,
        // setting up a new template subscription, so there have now existed two subscriptions on myObservable...
        myModel.subModel({ myObservable: myObservable });
        expect(testNode.childNodes[0].childNodes[0]).not.toEqual(renderedNode1);

        // ...but, because the old subscription should have been disposed automatically, there should only be one left
        expect(myObservable.getSubscriptionsCount()).toEqual(1);
    });

    it('Should be able to specify a template engine instance using data-bind syntax', function() {
        ko.setTemplateEngine(new dummyTemplateEngine({ theTemplate: "Default output" })); // Not going to use this one
        var alternativeTemplateEngine = new dummyTemplateEngine({ theTemplate: "Alternative output" });

        testNode.innerHTML = "<div data-bind='template: { name: \"theTemplate\", templateEngine: chosenEngine }'></div>";
        ko.applyBindings({ chosenEngine: alternativeTemplateEngine }, testNode);

        expect(testNode.childNodes[0]).toContainText("Alternative output");
    });

    it('Should be able to bind $data to an alias using \'as\'', function() {
        ko.setTemplateEngine(new dummyTemplateEngine({
            myTemplate: "ValueLiteral: [js:item.prop], ValueBound: <span data-bind='text: item.prop'></span>"
        }));
        testNode.innerHTML = "<div data-bind='template: { name: \"myTemplate\", data: someItem, as: \"item\" }'></div>";
        ko.applyBindings({ someItem: { prop: 'Hello' } }, testNode);
        expect(testNode.childNodes[0]).toContainText("ValueLiteral: Hello, ValueBound: Hello");
    });

    it('Data-bind syntax should expose parent binding context as $parent if binding with an explicit \"data\" value', function() {
        ko.setTemplateEngine(new dummyTemplateEngine({
            myTemplate: "ValueLiteral: [js:$parent.parentProp], ValueBound: <span data-bind='text: $parent.parentProp'></span>"
        }));
        testNode.innerHTML = "<div data-bind='template: { name: \"myTemplate\", data: someItem }'></div>";
        ko.applyBindings({ someItem: {}, parentProp: 'Hello' }, testNode);
        expect(testNode.childNodes[0]).toContainText("ValueLiteral: Hello, ValueBound: Hello");
    });

    it('Data-bind syntax should expose all ancestor binding contexts as $parents', function() {
        ko.setTemplateEngine(new dummyTemplateEngine({
            outerTemplate:  "<div data-bind='template: { name:\"middleTemplate\", data: middleItem }'></div>",
            middleTemplate: "<div data-bind='template: { name: \"innerTemplate\", data: innerItem }'></div>",
            innerTemplate:  "(Data:[js:$data.val], Parent:[[js:$parents[0].val]], Grandparent:[[js:$parents[1].val]], Root:[js:$root.val], Depth:[js:$parents.length])"
        }));
        testNode.innerHTML = "<div data-bind='template: { name: \"outerTemplate\", data: outerItem }'></div>";

        ko.applyBindings({
            val: "ROOT",
            outerItem: {
                val: "OUTER",
                middleItem: {
                    val: "MIDDLE",
                    innerItem: { val: "INNER" }
                }
            }
        }, testNode);
        expect(testNode.childNodes[0].childNodes[0]).toContainText("(Data:INNER, Parent:MIDDLE, Grandparent:OUTER, Root:ROOT, Depth:3)");
    });

    it('Should not be allowed to rewrite templates that embed anonymous templates', function() {
        // The reason is that your template engine's native control flow and variable evaluation logic is going to run first, independently
        // of any KO-native control flow, so variables would get evaluated in the wrong context. Example:
        //
        // <div data-bind="foreach: someArray">
        //     ${ somePropertyOfEachArrayItem }   <-- This gets evaluated *before* the foreach binds, so it can't reference array entries
        // </div>
        //
        // It should be perfectly OK to fix this just by preventing anonymous templates within rewritten templates, because
        // (1) The developer can always use their template engine's native control flow syntax instead of the KO-native ones - that will work
        // (2) The developer can use KO's native templating instead, if they are keen on KO-native control flow or anonymous templates

        ko.setTemplateEngine(new dummyTemplateEngine({
            myTemplate: "<div data-bind='template: { data: someData }'>Childprop: [js: childProp]</div>"
        }));
        testNode.innerHTML = "<div data-bind='template: { name: \"myTemplate\" }'></div>";

        expect(function () {
            ko.applyBindings({ someData: { childProp: 'abc' } }, testNode);
        }).toThrowContaining("This template engine does not support anonymous templates nested within its templates");
    });

    it('Should not be allowed to rewrite templates that embed control flow bindings', function() {
        // Same reason as above (also include binding names with quotes and spaces to show that formatting doesn't matter)
        ko.utils.arrayForEach(['if', 'ifnot', 'with', 'foreach', '"if"', ' with '], function(bindingName) {
            ko.setTemplateEngine(new dummyTemplateEngine({ myTemplate: "<div data-bind='" + bindingName + ": \"SomeValue\"'>Hello</div>" }));
            testNode.innerHTML = "<div data-bind='template: { name: \"myTemplate\" }'></div>";

            ko.utils.domData.clear(testNode);
            expect(function () {
                ko.applyBindings({ someData: { childProp: 'abc' } }, testNode);
            }).toThrowContaining("This template engine does not support");
        });
    });

    it('Data binding syntax should permit nested templates using virtual containers (with arbitrary internal whitespace and newlines)', function() {
        ko.setTemplateEngine(new dummyTemplateEngine({
            outerTemplate: "Outer <!-- ko template: \n" +
                "{ name: \"innerTemplate\" } \n" +
                "--><!-- /ko -->",
            innerTemplate: "Inner via inline binding: <span data-bind='text: \"someText\"'></span>"
        }));
        var model = { };
        testNode.innerHTML = "<div data-bind='template: { name: \"outerTemplate\" }'></div>";
        ko.applyBindings(model, testNode);
        expect(testNode.childNodes[0]).toContainHtml("outer <!-- ko -->inner via inline binding: <span>sometext</span><!-- /ko -->");
    });

    it('Should be able to render anonymous templates using virtual containers', function() {
        ko.setTemplateEngine(new dummyTemplateEngine());
        testNode.innerHTML = "Start <!-- ko template: { data: someData } -->Childprop: [js: childProp]<!-- /ko --> End";
        ko.applyBindings({ someData: { childProp: 'abc' } }, testNode);
        expect(testNode).toContainHtml("start <!-- ko template: { data: somedata } -->childprop: abc<!-- /ko -->end");
    });

    it('Should be able to use anonymous templates that contain first-child comment nodes', function() {
        // This represents issue https://github.com/SteveSanderson/knockout/issues/188
        // (IE < 9 strips out leading comment nodes when you use .innerHTML)
        ko.setTemplateEngine(new dummyTemplateEngine({}));
        testNode.innerHTML = "start <div data-bind='foreach: [1,2]'><span><!-- leading comment -->hello</span></div>";
        ko.applyBindings(null, testNode);
        expect(testNode).toContainHtml('start <div data-bind="foreach: [1,2]"><span><!-- leading comment -->hello</span><span><!-- leading comment -->hello</span></div>');
    });

    it('Should allow anonymous templates output to include top-level virtual elements, and will bind their virtual children only once', function() {
        delete ko.bindingHandlers.nonexistentHandler;
        var initCalls = 0;
        ko.bindingHandlers.countInits = { init: function () { initCalls++ } };
        testNode.innerHTML = "<div data-bind='template: {}'><!-- ko nonexistentHandler: true --><span data-bind='countInits: true'></span><!-- /ko --></div>";
        ko.applyBindings(null, testNode);
        expect(initCalls).toEqual(1);
    });

    it('Should be possible to combine template rewriting, foreach, and a node preprocessor', function() {
        this.restoreAfter(ko.bindingProvider, 'instance');

        // This spec verifies that the use of fixUpContinuousNodeArray in templating.js correctly handles the scenario
        // where a memoized comment node is the first node outputted by 'foreach', and it gets removed by unmemoization.
        // In this case we rely on fixUpContinuousNodeArray to work out which remaining nodes correspond to the 'foreach'
        // output so they can later be removed when the model array changes.
        var originalBindingProvider = ko.bindingProvider.instance,
            preprocessingBindingProvider = function() { };
        preprocessingBindingProvider.prototype = originalBindingProvider;
        ko.bindingProvider.instance = new preprocessingBindingProvider();
        ko.bindingProvider.instance.preprocessNode = function(node) {
            // This preprocessor doesn't change the rendered nodes. But simply having a preprocessor means
            // that templating.js has to recompute which DOM nodes correspond to the foreach output, since
            // you might have modified that set.
            return [node];
        };

        ko.setTemplateEngine(new dummyTemplateEngine({}));
        testNode.innerHTML = "<div data-bind='template: { foreach: items }'><button data-bind='text: $data'></button> OK. </div>";
        var items = ko.observableArray(['Alpha', 'Beta']);
        ko.applyBindings({ items: items }, testNode);
        expect(testNode).toContainText('Alpha OK. Beta OK. ');

        // Check that 'foreach' knows which set of elements to remove when an item vanishes from the model array,
        // even though the original 'foreach' output's first node, the memo comment, was removed during unmemoization.
        items.shift();
        expect(testNode).toContainText('Beta OK. ');
    });

    it('Should not throw errors if trying to apply text to a non-rendered node', function() {
        // Represents https://github.com/SteveSanderson/knockout/issues/660
        // A <span> can't go directly into a <tr>, so modern browsers will silently strip it. We need to verify this doesn't
        // throw errors during unmemoization (when unmemoizing, it will try to apply the text to the following text node
        // instead of the node you intended to bind to).
        // Note that IE < 9 won't strip the <tr>; instead it has much stranger behaviors regarding unexpected DOM structures.
        // It just happens not to give an error in this particular case, though it would throw errors in many other cases
        // of malformed template DOM.
        ko.setTemplateEngine(new dummyTemplateEngine({
            myTemplate: "<tr><span data-bind=\"text: 'Some text'\"></span> </tr>" // The whitespace after the closing span is what triggers the strange HTML parsing
        }));
        testNode.innerHTML = "<div data-bind='template: \"myTemplate\"'></div>";
        ko.applyBindings(null, testNode);
        // Since the actual template markup was invalid, we don't really care what the
        // resulting DOM looks like. We are only verifying there were no exceptions.
    });

    it('Should be possible to render a template to a document fragment', function() {
        // Represents https://github.com/knockout/knockout/issues/1162
        // This was failing on IE8
        ko.setTemplateEngine(new dummyTemplateEngine({
            myTemplate: "<p>myval: [js: myVal]</p>" // The whitespace after the closing span is what triggers the strange HTML parsing
        }));

        var testDocFrag = document.createDocumentFragment();
        ko.renderTemplate("myTemplate", { myVal: 123 }, null, testDocFrag);

        // Can't use .toContainHtml directly on doc frags, so check DOM structure manually
        expect(testDocFrag.childNodes.length).toEqual(1);
        expect(testDocFrag.childNodes[0].tagName).toEqual("P");
        expect(testDocFrag.childNodes[0]).toContainHtml("myval: 123");
    });
});