NativeScript/tests/app/ui/core/bindable/bindable-tests.ts

import { Observable, fromObject, fromObjectRecursive } from "@nativescript/core/data/observable";
import { ViewBase } from "@nativescript/core/ui/core/view-base";
import { BindingOptions } from "@nativescript/core/ui/core/bindable";
import * as TKUnit from "../../../tk-unit";
import * as types from "@nativescript/core/utils/types";
import * as helper from "../../../ui-helper";
import * as utils from "@nativescript/core/utils/utils";
import * as bindingBuilder from "@nativescript/core/ui/builder/binding-builder";
import * as appModule from "@nativescript/core/application";
import * as trace from "@nativescript/core/trace";
import { View } from "@nativescript/core/ui/core/view";
import { Button } from "@nativescript/core/ui/button";
import { Page } from "@nativescript/core/ui/page";
import { StackLayout } from "@nativescript/core/ui/layouts/stack-layout";
import { Label } from "@nativescript/core/ui/label";
import { TextField } from "@nativescript/core/ui/text-field";

// <snippet module="ui/core/bindable" title="bindable">
// For information and examples how to use bindings please refer to special [**Data binding**](../../../../bindings.md) topic.
// </snippet>

// <snippet module="ui/core/weak-event-listener" title="weak-event-listener">
// For information and example how to use weak event listeners please refer to special [**Events**](../../../../events.md) topic which has a dedicated part about weak event listeners.
// </snippet>

export function test_Bindable_Members() {
    const obj = new Label();
    TKUnit.assert(types.isDefined(obj.bind), "Bindable.bind not defined");
    TKUnit.assert(types.isDefined(obj.unbind), "Bindable.unbind not defined");
}

export function test_Binding_to_bindingContext_of_View() {
    const target = new Button();
    const source = new Button();

    target.bind({ targetProperty: "bindingContext", sourceProperty: "text" }, source);
    source.text = "a";
    TKUnit.assertEqual(target.bindingContext, "a");
}

export function test_Bindable_Bind_ToTarget_OneWay() {
    const model = new Observable();
    model.set("name", "John");

    const options: BindingOptions = {
        sourceProperty: "name",
        targetProperty: "text"
    };

    const obj = new Label();
    obj.bind(options, model);

    TKUnit.assert(obj.get("text") === "John", "Expected result after binding is [test value] === 'John'");

    model.set("name", "Changed");

    TKUnit.assert(obj.get("text") === "Changed", "Expected result after binding is [test value] === 'Changed'");
}

export function test_Bindable_Bind_ToTarget_TwoWay() {
    const model = new Observable();
    model.set("name", "John");

    const options: BindingOptions = {
        sourceProperty: "name",
        targetProperty: "text",
        twoWay: true
    };

    const obj = new Label();
    obj.bind(options, model);
    obj.set("text", "Changed");

    TKUnit.assertEqual(model.get("name"), "Changed", "Two-way binding not updating the source when target is changed.");

    model.set("name", "John");

    TKUnit.assertEqual(obj.get("text"), "John", "Two-way binding not updating the target when source is changed.");
}

export function test_Bindable_Bind_ToBindingContext_OneWay() {
    const model = new Observable();
    model.set("name", "John");

    const options: BindingOptions = {
        sourceProperty: "name",
        targetProperty: "text"
    };

    const obj = new Label();
    obj.bind(options);
    obj.set("text", "local");
    obj.bindingContext = model;

    TKUnit.assert(obj.get("text") === "John", "Binding to a context does not update the target property.");
}

export function test_Bindable_Bind_ToBindingContext_TwoWay() {
    const model = new Observable();
    model.set("name", "John");

    const options: BindingOptions = {
        sourceProperty: "name",
        targetProperty: "text",
        twoWay: true
    };

    const obj = new Label();
    obj.bind(options);

    obj.set("text", "local");
    obj.bindingContext = model;

    TKUnit.assertEqual(obj.get("text"), "John", "Binding to a context does not update the target property.");

    obj.set("text", "local");

    TKUnit.assertEqual(model.get("name"), "local", "Two-way binding to a context does not update the source property.");
}

export function test_Bindable_Unbind() {
    const model = new Observable();

    const options: BindingOptions = {
        sourceProperty: "name",
        targetProperty: "text"
    };

    const obj = new Label();
    obj.bind(options, model);

    model.set("name", "John");

    TKUnit.assert(obj.get("text") === "John", "Binding does not updates target property.");

    obj.unbind("text");
    model.set("name", "Changed");

    TKUnit.assert(obj.get("text") === "John", "Unbind does not remove binding.");
}

export function test_bind_NoSource_WillUse_BindingContext() {
    const model = new Observable();
    model.set("testProperty", "testValue");

    const test = function (views: Array<View>) {
        views[0].bindingContext = model;
        views[1].bind({
            sourceProperty: "testProperty",
            targetProperty: "text"
        });

        const button = <Button>views[1];
        TKUnit.assertEqual(button.text, model.get("testProperty"), "Bind method not working when no source is passed but a valid bindingContext is present.");
    };

    helper.do_PageTest_WithButton(test);
}

export function test_bindingContext_ValueSource_IsInherited() {
    const test = function (views: Array<View>) {
        const context = {};
        views[0].bindingContext = context;
        TKUnit.assert(views[1].bindingContext === context, "bindingContext not inherited.");
    };

    helper.do_PageTest_WithButton(test);
}

export function test_bindingContext_Change_IsReflected_Properly() {
    const model = new Observable();
    model.set("testProperty", "testValue");

    const test = function (views: Array<View>) {
        views[1].bind({
            sourceProperty: "testProperty",
            targetProperty: "text"
        });

        const button = <Button>views[1];
        TKUnit.assert(button.text === "", "Bind should do nothing when no source and binding context are available.");

        views[0].bindingContext = model;
        TKUnit.assert(button.text === "testValue", "Binding not updated properly when a valid bindingContext is provided.");

        views[0].bindingContext = undefined;
        model.set("testProperty", "updatedValue");
        TKUnit.assertEqual(button.text, "", "Binding not properly detached when bindingContext is cleared.");
    };

    helper.do_PageTest_WithButton(test);
}

export function test_WhenBindingIsSetToAnElement_AndElementIsRemoved_ShouldBeCollectedByGC(done) {
    let testFinished = false;

    let page = helper.getCurrentPage();
    let stack = new StackLayout();

    let expectedValue = "testValue";
    let sourcePropertyName = "testProperty";
    let targetPropertyName = "text";

    stack.on(View.loadedEvent, () => {
        const model = new Observable();
        model.set(sourcePropertyName, expectedValue);

        function createButton(bindContext) {
            let button = new Button();
            button.bind({
                sourceProperty: sourcePropertyName,
                targetProperty: targetPropertyName
            }, bindContext);

            return new WeakRef(button);
        }

        const weakRef = createButton(model);

        try {
            stack.addChild(weakRef.get());
            TKUnit.waitUntilReady(() => weakRef.get().isLoaded);

            TKUnit.assertEqual(weakRef.get().text, expectedValue, "Binding is not working properly!");
            stack.removeChild(weakRef.get());
            TKUnit.waitUntilReady(() => !weakRef.get().isLoaded);

            utils.GC();
            // Give time for the GC to kick in
            setTimeout(() => {
                utils.GC();
                TKUnit.assert(!weakRef.get(), "UIElement is still alive!");
                testFinished = true;
            }, 100);
        }
        catch (e) {
            done(e);
        }
    });

    page.content = stack;

    TKUnit.waitUntilReady(() => testFinished);
    done(null);
}

export function test_OneBindableToBindMoreThanOneProperty_ToSameSource() {
    const model = new Observable();

    const firstPropertyOptions: BindingOptions = {
        sourceProperty: "name",
        targetProperty: "text"
    };

    const secondPropertyOptions: BindingOptions = {
        sourceProperty: "sourceProperty",
        targetProperty: "targetProperty"
    };

    const obj = new Label();
    obj.bind(firstPropertyOptions, model);
    obj.bind(secondPropertyOptions, model);

    model.set("name", "John");
    model.set("sourceProperty", "testValue");

    TKUnit.assertEqual(obj.get("text"), "John", "Binding does not updates target property.");
    TKUnit.assertEqual(obj.get("targetProperty"), "testValue", "Binding does not updates target property1.");
}

export function test_MoreThanOneBindables_BindToASameSourceAndProperty() {
    const model = new Observable();

    const bindingOptions: BindingOptions = {
        sourceProperty: "sourceProperty",
        targetProperty: "targetProperty"
    };

    const obj1 = new Label();
    obj1.bind(bindingOptions, model);

    const obj2 = new Label();
    obj2.bind(bindingOptions, model);

    model.set("sourceProperty", "testValue");

    TKUnit.assertEqual(obj1.get("targetProperty"), "testValue", "Binding does not updates target property for first object.");
    TKUnit.assertEqual(obj2.get("targetProperty"), "testValue", "Binding does not updates target property for second object.");
}

class TestClass extends ViewBase {
    private _value: string;
    get value(): string {
        return this._value;
    }
    set value(v: string) {
        if (v === "invalid") {
            throw new Error("Trying to set invalid value.");
        }
        this._value = v;
    }
}

export function test_WhenBindingSetsInvalidValue_NoExceptionIsThrown() {
    const model = new Observable();

    const options: BindingOptions = {
        sourceProperty: "value",
        targetProperty: "value"
    };

    const obj = new TestClass();
    obj.bind(options, model);

    model.set("value", "valid");
    TKUnit.assert(obj.get("value") === "valid");

    // Try set invalid value - no exception should be thrown and the value should remain the same.
    model.set("value", "invalid");
    TKUnit.assert(obj.get("value") === "valid");
}

export function test_binding_bindingContext_setRootContextFirst() {
    const test = function (views: Array<View>) {
        const rootContext = new Observable();
        rootContext.set("selectedItem", "item 1");
        views[0].bindingContext = rootContext;

        const stack = <StackLayout>views[1];
        const options: BindingOptions = {
            sourceProperty: "selectedItem",
            targetProperty: "bindingContext"
        };
        stack.bind(options);

        TKUnit.assertEqual(stack.bindingContext, "item 1", "Initial binding value");
        TKUnit.assertEqual(views[2].bindingContext, "item 1", "Initial binding value");

        rootContext.set("selectedItem", "item 2");

        TKUnit.assertEqual(stack.bindingContext, "item 2", "Changed binding value");
        TKUnit.assertEqual(views[2].bindingContext, "item 2", "Changed binding value");
    };

    helper.do_PageTest_WithStackLayout_AndButton(test);
}

export function test_binding_bindingContext_setBindingFirst() {
    const test = function (views: Array<View>) {
        const rootContext = new Observable();
        rootContext.set("selectedItem", "item 1");

        const stack = <StackLayout>views[1];
        const options: BindingOptions = {
            twoWay: true,
            sourceProperty: "selectedItem",
            targetProperty: "bindingContext"
        };
        stack.bind(options);

        views[0].bindingContext = rootContext;

        TKUnit.assertEqual(stack.bindingContext, "item 1", "Initial binding value");
        TKUnit.assertEqual(views[2].bindingContext, "item 1", "Initial binding value");

        rootContext.set("selectedItem", "item 2");

        TKUnit.assertEqual(stack.bindingContext, "item 2", "Changed binding value");
        TKUnit.assertEqual(views[2].bindingContext, "item 2", "Changed binding value");
    };

    helper.do_PageTest_WithStackLayout_AndButton(test);
}

export function test_Bindable_BindingContext_Number_DoesNotThrow() {
    const obj = new Label();
    obj.bindingContext = 42;
}

export function test_Bindable_BindingContext_Boolean_DoesNotThrow() {
    const obj = new Label();
    obj.bindingContext = true;
}

export function test_Bindable_BindingContext_String_DoesNotThrow() {
    const options: BindingOptions = {
        sourceProperty: "length",
        targetProperty: "text"
    };

    const obj = new Label();
    obj.bind(options);
    obj.set("text", "local");
    obj.bindingContext = "string";

    TKUnit.assert(obj.get("text") === 6, "Expected: 6; Actual: " + obj.get("text"));
}

export function test_getBindableOptionsFromStringFullFormat() {
    const bindingExpression = "bindProperty, bindProperty * 2, false";
    const bindOptions = bindingBuilder.getBindingOptions("targetBindProperty", bindingExpression);

    TKUnit.assert(bindOptions.sourceProperty === "bindProperty", "Expected: bindProperty, Actual: " + bindOptions.sourceProperty);
    TKUnit.assert(bindOptions.targetProperty === "targetBindProperty", "Expected: targetBindProperty, Actual: " + bindOptions.targetProperty);
    TKUnit.assert(bindOptions.expression === "bindProperty * 2", "Expected: bindProperty * 2, Actual:" + bindOptions.expression);
    TKUnit.assert(bindOptions.twoWay === false, "Expected: false, Actual: " + bindOptions.twoWay);
}

export function test_getBindableOptionsFromStringShortFormatExpression() {
    const bindingExpression = "bindProperty * 2";
    const bindOptions = bindingBuilder.getBindingOptions("targetBindProperty", bindingExpression);

    TKUnit.assert(bindOptions.sourceProperty === "$value", "Expected: bindProperty, Actual: " + bindOptions.sourceProperty);
    TKUnit.assert(bindOptions.targetProperty === "targetBindProperty", "Expected: targetBindProperty, Actual: " + bindOptions.targetProperty);
    TKUnit.assert(bindOptions.expression === "bindProperty * 2", "Expected: bindProperty * 2, Actual: " + bindOptions.expression);
    TKUnit.assert(bindOptions.twoWay === true, "Expected: true, Actual: " + bindOptions.twoWay);
}

export function test_getBindableOptionsFromStringShortFormatProperty() {
    const bindingExpression = "bindProperty";
    const bindOptions = bindingBuilder.getBindingOptions("targetBindProperty", bindingExpression);

    TKUnit.assert(bindOptions.sourceProperty === "bindProperty", "Expected: bindProperty, Actual: " + bindOptions.sourceProperty);
    TKUnit.assert(bindOptions.targetProperty === "targetBindProperty", "Expected: targetBindProperty, Actual: " + bindOptions.targetProperty);
    TKUnit.assert(bindOptions.expression === undefined, "Expected: null, Actual: " + bindOptions.expression);
    TKUnit.assert(bindOptions.twoWay === true, "Expected: true, Actual: " + bindOptions.twoWay);
}

export function test_getBindableOptionsFromStringTwoParamsFormat() {
    const bindingExpression = "bindProperty, bindProperty * 2";
    const bindOptions = bindingBuilder.getBindingOptions("targetBindProperty", bindingExpression);

    TKUnit.assert(bindOptions.sourceProperty === "bindProperty", "Expected: bindProperty, Actual: " + bindOptions.sourceProperty);
    TKUnit.assert(bindOptions.targetProperty === "targetBindProperty", "Expected: targetBindProperty, Actual: " + bindOptions.targetProperty);
    TKUnit.assert(bindOptions.expression === "bindProperty * 2", "Expected: bindProperty * 2, Actual:" + bindOptions.expression);
    TKUnit.assert(bindOptions.twoWay === true, "Expected: true, Actual: " + bindOptions.twoWay);
}

export function test_getBindableOptionsFromStringFullNamedFormat() {
    const bindingExpression = "bindProperty, expression = bindProperty * 2, twoWay = false";
    const bindOptions = bindingBuilder.getBindingOptions("targetBindProperty", bindingExpression);

    TKUnit.assert(bindOptions.sourceProperty === "bindProperty", "Expected: bindProperty, Actual: " + bindOptions.sourceProperty);
    TKUnit.assert(bindOptions.targetProperty === "targetBindProperty", "Expected: targetBindProperty, Actual: " + bindOptions.targetProperty);
    TKUnit.assert(bindOptions.expression === "bindProperty * 2", "Expected: bindProperty * 2, Actual:" + bindOptions.expression);
    TKUnit.assert(bindOptions.twoWay === false, "Expected: false, Actual: " + bindOptions.twoWay);
}

export function test_getBindableOptionsFromStringShortNamedFormatExpression() {
    const bindingExpression = "sourceProperty = bindProperty, expression = bindProperty * 2";
    const bindOptions = bindingBuilder.getBindingOptions("targetBindProperty", bindingExpression);

    TKUnit.assert(bindOptions.sourceProperty === "bindProperty", "Expected: bindProperty, Actual: " + bindOptions.sourceProperty);
    TKUnit.assert(bindOptions.targetProperty === "targetBindProperty", "Expected: targetBindProperty, Actual: " + bindOptions.targetProperty);
    TKUnit.assert(bindOptions.expression === "bindProperty * 2", "Expected: bindProperty * 2, Actual: " + bindOptions.expression);
    TKUnit.assert(bindOptions.twoWay === true, "Expected: true, Actual: " + bindOptions.twoWay);
}

export function test_getBindableOptionsFromStringShortNamedFormatProperty() {
    const bindingExpression = "sourceProperty = bindProperty";
    const bindOptions = bindingBuilder.getBindingOptions("targetBindProperty", bindingExpression);
    TKUnit.assert(bindOptions.sourceProperty === "bindProperty", "Expected: bindProperty, Actual: " + bindOptions.sourceProperty);
    TKUnit.assert(bindOptions.targetProperty === "targetBindProperty", "Expected: targetBindProperty, Actual: " + bindOptions.targetProperty);
    TKUnit.assert(bindOptions.expression === undefined, "Expected: null, Actual: " + bindOptions.expression);
    TKUnit.assert(bindOptions.twoWay === true, "Expected: true, Actual: " + bindOptions.twoWay);
}

export function test_getBindableOptionsFromStringTwoParamsNamedFormat() {
    const bindingExpression = "bindProperty, expression = bindProperty * 2";
    const bindOptions = bindingBuilder.getBindingOptions("targetBindProperty", bindingExpression);

    TKUnit.assert(bindOptions.sourceProperty === "bindProperty", "Expected: bindProperty, Actual: " + bindOptions.sourceProperty);
    TKUnit.assert(bindOptions.targetProperty === "targetBindProperty", "Expected: targetBindProperty, Actual: " + bindOptions.targetProperty);
    TKUnit.assert(bindOptions.expression === "bindProperty * 2", "Expected: bindProperty * 2, Actual:" + bindOptions.expression);
    TKUnit.assert(bindOptions.twoWay === true, "Expected: true, Actual: " + bindOptions.twoWay);
}

export function test_getBindingOptionsFromStringWithFunctionWitnMoreParams() {
    const bindingExpression = "bindProperty, converter(bindProperty, param1)";
    const bindOptions = bindingBuilder.getBindingOptions("targetBindProperty", bindingExpression);

    TKUnit.assertEqual(bindOptions.sourceProperty, "bindProperty");
    TKUnit.assertEqual(bindOptions.targetProperty, "targetBindProperty");
    TKUnit.assertEqual(bindOptions.expression, "converter(bindProperty, param1)");
    TKUnit.assertEqual(bindOptions.twoWay, true);
}

export function test_getBindingOptionsFromStringWithFunctionArrayParams() {
    const bindingExpression = "bindProperty, converter(bindProperty, [param1, param2])";
    const bindOptions = bindingBuilder.getBindingOptions("targetBindProperty", bindingExpression);

    TKUnit.assertEqual(bindOptions.sourceProperty, "bindProperty");
    TKUnit.assertEqual(bindOptions.targetProperty, "targetBindProperty");
    TKUnit.assertEqual(bindOptions.expression, "converter(bindProperty, [param1, param2])");
    TKUnit.assertEqual(bindOptions.twoWay, true);
}

export function test_bindingToNestedPropertyWithValueSyntax() {
    const bindingSource = new Observable();
    bindingSource.set("testProperty", "testValue");

    const testElement = new Label();
    testElement.bind({
        sourceProperty: "$value.testProperty",
        targetProperty: "targetPropertyName"
    }, bindingSource);

    TKUnit.assertEqual(testElement.get("targetPropertyName"), "testValue");
    TKUnit.assertTrue(bindingSource["$value"] === undefined, "We should not add $value to bindingSource.");
}

export function test_TwoElementsBindingToSameBindingContext() {
    const testFunc = function (page: Page) {
        const upperStackLabel = <Label>(page.getViewById("upperStackLabel"));
        const label1 = <Label>(page.getViewById("label1"));
        const label2 = <Label>(page.getViewById("label2"));

        TKUnit.assertEqual(upperStackLabel.text, label1.text, "label1");
        TKUnit.assertEqual(upperStackLabel.text, label2.text, "label2");
    };
    helper.navigateToModuleAndRunTest(("ui/core/bindable/bindingContext_testPage"), null, testFunc);
}

export function test_BindingContext_NavigatingForwardAndBack() {
    const expectedValue = "Tralala";
    const testFunc = function (page: Page) {
        const innerTestFunc = function (childPage: Page) {
            const testTextField: TextField = <TextField>(childPage.getViewById("testTextField"));
            testTextField.text = expectedValue;
        };
        helper.navigateToModuleAndRunTest(("ui/core/bindable/bindingContext_testPage2"), page.bindingContext, innerTestFunc);
        const testLabel: Label = <Label>(page.getViewById("testLabel"));
        TKUnit.assertEqual(testLabel.text, expectedValue);
    };

    helper.navigateToModuleAndRunTest(("ui/core/bindable/bindingContext_testPage1"), null, testFunc);
}

export function test_BindingToSource_FailsAfterBindingContextChange() {
    const createLabel = function () {
        const label = new Label();

        return label;
    };
    const labelViewModel = new Observable();
    const expectedValue = "testValue";
    labelViewModel.set("testProperty", expectedValue);

    const testFunc = function (views: Array<View>) {
        const testLabel = <Label>(views[0]);
        testLabel.bind({ sourceProperty: "testProperty", targetProperty: "text" }, labelViewModel);

        const page = <Page>(views[1]);
        page.bindingContext = new Observable;

        TKUnit.assertEqual(testLabel.text, expectedValue);
    };

    helper.buildUIAndRunTest(createLabel(), testFunc);
}

export function test_BindingToParentView_ShouldNotLeaveGarbageInViewModel() {
    const createStack = function () {
        const stack = new StackLayout();
        const label = new Label();
        stack.addChild(label);

        return stack;
    };
    const stackViewModel = new Observable();
    const expectedValue = "testValue";
    stackViewModel.set("testProperty", expectedValue);

    const testFunc = function (views: Array<View>) {
        let testStack = <StackLayout>(views[0]);
        testStack.bindingContext = stackViewModel;

        let testLabel = <Label>(testStack.getChildAt(0));
        testLabel.bind({ sourceProperty: "$parent.testProperty", targetProperty: "text", expression: "$parent.testProperty" });

        TKUnit.assertEqual(testLabel.text, expectedValue);
        TKUnit.assertTrue(stackViewModel["$parent"] === undefined, "stackViewModel['$parent'] should be removed from parent binding context.");
        TKUnit.assertTrue(testLabel.bindingContext["$parent"] === undefined, "testLabel.bindingContext['$parent'] should be removed from parent binding context.");
    };

    helper.buildUIAndRunTest(createStack(), testFunc);
}

export function test_BindingToParentsView_ShouldNotLeaveGarbageInViewModel() {
    const createStack = function () {
        const stack = new StackLayout();
        const label = new Label();
        stack.addChild(label);

        return stack;
    };
    const stackViewModel = new Observable();
    const expectedValue = "testValue";
    stackViewModel.set("testProperty", expectedValue);

    const testFunc = function (views: Array<View>) {
        let testStack = <StackLayout>(views[0]);
        testStack.bindingContext = stackViewModel;

        let testLabel = <Label>(testStack.getChildAt(0));
        testLabel.bind({ sourceProperty: "$parents['StackLayout'].testProperty", targetProperty: "text", expression: "$parents['StackLayout'].testProperty" });

        TKUnit.assertEqual(testLabel.text, expectedValue);
        TKUnit.assertTrue(stackViewModel["$parent"] === undefined, "stackViewModel['$parent'] should be removed from parent binding context.");
        TKUnit.assertTrue(testLabel.bindingContext["$parents"] === undefined, "testLabel.bindingContext['$parents'] should be removed from parent binding context.");
    };

    helper.buildUIAndRunTest(createStack(), testFunc);
}

export function test_BindingToDictionaryAtAppLevel() {
    const createLabel = function () {
        const label = new Label();

        return label;
    };
    const pageViewModel = new Observable();
    const testPropertyName = "testValue";
    const expectedValue = "expectedValue";
    pageViewModel.set("testProperty", testPropertyName);
    const dict = {};
    dict[testPropertyName] = expectedValue;
    appModule.getResources()["dict"] = dict;

    const testFunc = function (views: Array<View>) {
        const testLabel = <Label>(views[0]);
        testLabel.bind({ sourceProperty: "testProperty", targetProperty: "text", expression: "dict[testProperty]" });

        const page = <Page>(views[1]);
        page.bindingContext = pageViewModel;

        TKUnit.assertEqual(testLabel.text, expectedValue);
        TKUnit.assertTrue(testLabel.bindingContext["dict"] === undefined, "BindingContext should not contain properties from application resources.");
    };

    helper.buildUIAndRunTest(createLabel(), testFunc);
}

export function test_BindingConverterCalledEvenWithNullValue() {
    const createLabel = function () {
        const label = new Label();

        return label;
    };
    const pageViewModel = new Observable();
    const testPropertyValue = null;
    const expectedValue = "collapsed";
    pageViewModel.set("testProperty", testPropertyValue);
    appModule.getResources()["converter"] = function (value) {
        if (value) {
            return "visible";
        } else {
            return "collapsed";
        }
    };

    const testFunc = function (views: Array<View>) {
        const testLabel = <Label>(views[0]);
        testLabel.bind({ sourceProperty: "testProperty", targetProperty: "text", expression: "testProperty | converter" });

        const page = <Page>(views[1]);
        page.bindingContext = pageViewModel;

        TKUnit.assertEqual(testLabel.text, expectedValue);
    };

    helper.buildUIAndRunTest(createLabel(), testFunc);
}

export function test_UpdatingNestedPropertyViaBinding() {
    const expectedValue1 = "Alabala";
    const expectedValue2 = "Tralala";
    const viewModel = new Observable();
    const parentViewModel = new Observable();
    viewModel.set("parentView", parentViewModel);
    parentViewModel.set("name", expectedValue1);

    const testElement = new Label();

    testElement.bind({
        sourceProperty: "parentView.name",
        targetProperty: "text",
        twoWay: true
    }, viewModel);

    const testElement2 = new Label();

    testElement2.bind({
        sourceProperty: "parentView.name",
        targetProperty: "text",
        twoWay: true
    }, viewModel);

    TKUnit.assertEqual(testElement.get("text"), expectedValue1);

    testElement.set("text", expectedValue2);

    TKUnit.assertEqual(parentViewModel.get("name"), expectedValue2);
    TKUnit.assertEqual(testElement2.get("text"), expectedValue2);
}

class Person extends Observable {
    private _firstName: string;
    private _lastName: string;

    public get FirstName(): string {
        return this._firstName;
    }

    public set FirstName(value: string) {
        if (this._firstName !== value) {
            this._firstName = value;
            this.notifyPropertyChange("FirstName", value);
        }
    }

    public get LastName(): string {
        return this._lastName;
    }

    public set LastName(value: string) {
        if (this._lastName !== value) {
            this._lastName = value;
            this.notifyPropertyChange("LastName", value);
        }
    }
}

class Activity extends Observable {
    private _text: string;
    private _owner: Person;

    public get Text(): string {
        return this._text;
    }

    public set Text(value: string) {
        if (this._text !== value) {
            this._text = value;
            this.notifyPropertyChange("Text", value);
        }
    }

    public get Owner(): Person {
        return this._owner;
    }

    public set Owner(value: Person) {
        if (this._owner !== value) {
            this._owner = value;
            this.notifyPropertyChange("Owner", value);
        }
    }

    constructor(text: string, firstName: string, lastName: string) {
        super();
        this._text = text;
        const owner = new Person();
        owner.FirstName = firstName;
        owner.LastName = lastName;
        this.Owner = owner;
    }
}

export function test_NestedPropertiesBinding() {
    const expectedValue = "Default Text";
    const viewModel = new Observable();
    viewModel.set("activity", new Activity(expectedValue, "Default First Name", "Default Last Name"));

    const target1 = new Label();
    target1.bind({
        sourceProperty: "activity.Text",
        targetProperty: "targetProperty",
        twoWay: true
    }, viewModel);

    TKUnit.assertEqual(target1.get("targetProperty"), expectedValue);

    const newExpectedValue = "Alabala";
    const act = new Activity(newExpectedValue, "Default First Name", "Default Last Name");

    viewModel.set("activity", act);

    TKUnit.assertEqual(target1.get("targetProperty"), newExpectedValue);
}

export function test_WrongNestedPropertiesBinding() {
    const expectedValue = "Default Text";
    const viewModel = new Observable();
    viewModel.set("activity", new Activity(expectedValue, "Default First Name", "Default Last Name"));
    let errorMessage;
    let traceWriter = {
        write: function (message, category, type?) {
            errorMessage = message;
        }
    };
    trace.addWriter(traceWriter);

    const target1 = new Label();
    target1.bind({
        sourceProperty: "activity.",
        targetProperty: "targetProperty",
        twoWay: true
    }, viewModel);

    TKUnit.assertNotEqual(errorMessage, undefined);
    trace.removeWriter(traceWriter);
}

export function test_NestedPropertiesBindingTwoTargets() {
    const expectedText = "Default Text";
    const expectedFirstName = "Default First Name";
    const expectedLastName = "Default Last Name";
    const viewModel = new Observable();
    viewModel.set("activity", new Activity(expectedText, expectedFirstName, expectedLastName));

    const target1 = new Label();
    target1.bind({
        sourceProperty: "activity.Text",
        targetProperty: "targetProperty",
        twoWay: true
    }, viewModel);

    const target2 = new Label();
    target2.bind({
        sourceProperty: "activity.Owner.FirstName",
        targetProperty: "targetProp",
        twoWay: true
    }, viewModel);

    TKUnit.assertEqual(target1.get("targetProperty"), expectedText);
    TKUnit.assertEqual(target2.get("targetProp"), expectedFirstName);

    const newExpectedText = "Alabala";
    const newExpectedFirstName = "First Tralala";
    const newExpectedLastName = "Last Tralala";
    const act = new Activity(newExpectedText, newExpectedFirstName, newExpectedLastName);

    viewModel.set("activity", act);

    TKUnit.assertEqual(target1.get("targetProperty"), newExpectedText);
    TKUnit.assertEqual(target2.get("targetProp"), newExpectedFirstName);
}

export function test_NestedPropertiesBindingTwoTargetsAndSecondChange() {
    const expectedText = "Default Text";
    const expectedFirstName = "Default First Name";
    const expectedLastName = "Default Last Name";
    const viewModel = new Observable();
    viewModel.set("activity", new Activity(expectedText, expectedFirstName, expectedLastName));

    const target1 = new Label();
    target1.bind({
        sourceProperty: "activity.Text",
        targetProperty: "targetProperty",
        twoWay: true
    }, viewModel);

    const target2 = new Label();
    target2.bind({
        sourceProperty: "activity.Owner.FirstName",
        targetProperty: "targetProp",
        twoWay: true
    }, viewModel);

    TKUnit.assertEqual(target1.get("targetProperty"), expectedText);
    TKUnit.assertEqual(target2.get("targetProp"), expectedFirstName);

    const newExpectedText = "Alabala";
    const newExpectedFirstName = "First Tralala";
    const newExpectedLastName = "Last Tralala";
    const act = new Activity(newExpectedText, newExpectedFirstName, newExpectedLastName);

    viewModel.set("activity", act);

    TKUnit.assertEqual(target1.get("targetProperty"), newExpectedText);
    TKUnit.assertEqual(target2.get("targetProp"), newExpectedFirstName);

    const secondExpectedText = "Second expected text";
    const secondExpectedFirstName = "Second expected first name";
    const secondExpectedLastName = "Second expected last name";
    const act1 = new Activity(secondExpectedText, secondExpectedFirstName, secondExpectedLastName);

    viewModel.set("activity", act1);

    TKUnit.assertEqual(target1.get("targetProperty"), secondExpectedText);
    TKUnit.assertEqual(target2.get("targetProp"), secondExpectedFirstName);
}

export function test_NestedPropertiesBindingTwoTargetsAndRegularChange() {
    const expectedText = "Default Text";
    const expectedFirstName = "Default First Name";
    const expectedLastName = "Default Last Name";
    const viewModel = new Observable();
    viewModel.set("activity", new Activity(expectedText, expectedFirstName, expectedLastName));

    const target1 = new Label();
    target1.bind({
        sourceProperty: "activity.Text",
        targetProperty: "targetProperty",
        twoWay: true
    }, viewModel);

    const target2 = new Label();
    target2.bind({
        sourceProperty: "activity.Owner.FirstName",
        targetProperty: "targetProp",
        twoWay: true
    }, viewModel);

    TKUnit.assertEqual(target1.get("targetProperty"), expectedText);
    TKUnit.assertEqual(target2.get("targetProp"), expectedFirstName);

    const newExpectedText = "Alabala";
    const newExpectedFirstName = "First Tralala";
    const newExpectedLastName = "Last Tralala";
    const act = new Activity(newExpectedText, newExpectedFirstName, newExpectedLastName);

    viewModel.set("activity", act);

    TKUnit.assertEqual(target1.get("targetProperty"), newExpectedText);
    TKUnit.assertEqual(target2.get("targetProp"), newExpectedFirstName);

    const newAct = viewModel.get("activity");
    const secondExpectedText = "Second expected text";
    newAct.Text = secondExpectedText;
    const secondExpectedFirstName = "Second expected First Name";
    newAct.Owner.FirstName = secondExpectedFirstName;

    TKUnit.assertEqual(target1.get("targetProperty"), secondExpectedText);
    TKUnit.assertEqual(target2.get("targetProp"), secondExpectedFirstName);
}

export function test_NestedPropertiesBindingTwoTargetsAndReplacingSomeNestedObject() {
    const expectedText = "Default Text";
    const expectedFirstName = "Default First Name";
    const expectedLastName = "Default Last Name";
    const viewModel = new Observable();
    viewModel.set("activity", new Activity(expectedText, expectedFirstName, expectedLastName));

    const target1 = new Label();
    target1.bind({
        sourceProperty: "activity.Text",
        targetProperty: "targetProperty",
        twoWay: true
    }, viewModel);

    const target2 = new Label();
    target2.bind({
        sourceProperty: "activity.Owner.FirstName",
        targetProperty: "targetProp",
        twoWay: true
    }, viewModel);

    TKUnit.assertEqual(target1.get("targetProperty"), expectedText);
    TKUnit.assertEqual(target2.get("targetProp"), expectedFirstName);

    const newExpectedText = "Alabala";
    const newExpectedFirstName = "First Tralala";
    const newExpectedLastName = "Last Tralala";
    const act = new Activity(newExpectedText, newExpectedFirstName, newExpectedLastName);

    viewModel.set("activity", act);

    TKUnit.assertEqual(target1.get("targetProperty"), newExpectedText);
    TKUnit.assertEqual(target2.get("targetProp"), newExpectedFirstName);

    const secondExpectedFirstName = "Second expected first name";
    const newPerson = new Person();
    newPerson.FirstName = secondExpectedFirstName;
    newPerson.LastName = "Last Name";

    const act1 = viewModel.get("activity");
    (<Activity>act1).Owner = newPerson;

    TKUnit.assertEqual(target2.get("targetProp"), secondExpectedFirstName);
}

export function test_NullSourcePropertyShouldNotCrash() {
    const expectedValue = "Expected Value";
    const target = new Label();
    const convFunc = function (value) {
        return value + "Converted";
    };
    const model = new Observable();
    model.set("field", expectedValue);
    model.set("convFunc", convFunc);
    target.bind({
        sourceProperty: null,
        targetProperty: "targetProp",
        expression: "convFunc(field)"
    }, model);

    TKUnit.assertEqual(target.get("targetProp"), convFunc(expectedValue));
}

export function test_BindingContextOfAChildElementIsNotOverwrittenBySettingTheBindingContextOfPage() {
    let testFinished = false;

    let page = helper.getCurrentPage();
    let child = new StackLayout();
    let childModel = new Observable();
    child.bindingContext = childModel;
    TKUnit.assertEqual(child.bindingContext, childModel);

    child.on(StackLayout.loadedEvent, (args) => {
        TKUnit.assertEqual(child.bindingContext, childModel);
        page.bindingContext = new Observable();
        TKUnit.assertEqual(child.bindingContext, childModel);
        child.off(StackLayout.loadedEvent);
        testFinished = true;
    });

    page.content = child;
    TKUnit.waitUntilReady(() => testFinished);
}

export function test_BindingHitsGetterTooManyTimes() {
    let counter = 0;

    class Dummy extends Observable {
        private _dummyProperty: string;

        public get dummyProperty(): string {
            counter++;

            return this._dummyProperty;
        }

        public set dummyProperty(value: string) {
            if (this._dummyProperty !== value) {
                this._dummyProperty = value;
                this.notifyPropertyChange("dummyProperty", value);
            }
        }
    }

    const model = new Dummy();
    model.dummyProperty = "OPA";

    const bindableObj = new Label();

    bindableObj.bind({ sourceProperty: "dummyProperty", targetProperty: "dummyTarget" }, model);

    TKUnit.assertEqual(counter, 1, "Property getter should be hit only once!");
}

export function test_SupportFunctionsInExpressions() {
    const model = fromObject({
        "anyColor": "red",
        "isVisible": function () {
            return this.get("anyColor") === "red";
        }
    });

    const bindableObj = new Label();

    bindableObj.bind({
        "sourceProperty": "$value",
        "targetProperty": "text",
        "expression": "isVisible() ? 'visible' : 'collapsed'"
    }, model);

    model.set("anyColor", "blue");

    TKUnit.assertEqual(bindableObj.get("text"), "collapsed", "When anyColor is blue test property should be collapsed.");

    model.set("anyColor", "red");

    TKUnit.assertEqual(bindableObj.get("text"), "visible", "When anyColor is red test property should be visible.");
}

export function test_$ValueSupportWithinExpression() {
    const model = fromObject({
        "anyColor": "red",
        "isVisible": function () {
            return this.get("anyColor") === "red";
        }
    });

    const bindableObj = new Label();

    bindableObj.bind({
        "sourceProperty": "$value",
        "targetProperty": "text",
        "expression": "$value.anyColor === 'red' ? 'red' : 'blue'"
    }, model);

    model.set("anyColor", "blue");

    TKUnit.assertEqual(bindableObj.get("text"), "blue", "When anyColor is blue test property should be blue too.");

    model.set("anyColor", "red");

    TKUnit.assertEqual(bindableObj.get("text"), "red", "When anyColor is red test property should be red too.");
    TKUnit.assertTrue(model["$value"] === undefined, "We should not add $value to binding context.");
}

class DummyNestedClass extends Observable {
    private _secondsobject: number;
    public get secondsobject(): number {
        return this._secondsobject;
    }
    public set secondsobject(value: number) {
        if (this._secondsobject !== value) {
            this._secondsobject = value;
            this.notifyPropertyChange("secondsobject", value);
        }
    }
}

class DummyClassWithSamePropertyNames extends Observable {
    private _seconds: number;
    private _secondsobject: DummyNestedClass;
    public get seconds(): number {
        return this._seconds;
    }
    public set seconds(value: number) {
        if (this._seconds !== value) {
            this._seconds = value;
            this.notifyPropertyChange("seconds", value);
        }
    }

    public get secondsobject(): DummyNestedClass {
        return this._secondsobject;
    }
    public set secondsobject(value: DummyNestedClass) {
        if (this._secondsobject !== value) {
            this._secondsobject = value;
            this.notifyPropertyChange("secondsobject", value);
        }
    }
}

class DummyModel extends Observable {
    private _item: DummyClassWithSamePropertyNames;
    public get item(): DummyClassWithSamePropertyNames {
        return this._item;
    }

    public set item(value: DummyClassWithSamePropertyNames) {
        if (this._item !== value) {
            this._item = value;
            this.notifyPropertyChange("item", value);
        }
    }
}

export function test_BindingToPropertiesWithSameNames() {
    const model = new DummyModel();
    model.item = new DummyClassWithSamePropertyNames();
    model.item.seconds = 1;
    const secondsobject = new DummyNestedClass();
    secondsobject.secondsobject = 1;
    model.item.secondsobject = secondsobject;

    const target1 = new Label();
    target1.bind({
        sourceProperty: "item.seconds",
        targetProperty: "targetProperty",
        twoWay: true
    }, model);

    const target2 = new Label();
    target2.bind({
        sourceProperty: "item.secondsobject.secondsobject",
        targetProperty: "targetProp",
        twoWay: true
    }, model);

    model.item.set("seconds", model.item.seconds + 1);
    let newValue = (<any>model).item.secondsobject.secondsobject + 1;
    model.item.secondsobject.set("secondsobject", newValue);

    TKUnit.assertEqual(target1.get("targetProperty"), model.item.get("seconds"));
    TKUnit.assertEqual(target2.get("targetProp"), newValue);

    // calling this two times in order to ensure that adding and removing weak event listeners is working fine.
    newValue = model.item.secondsobject.secondsobject + 1;
    model.item.secondsobject.set("secondsobject", newValue);

    TKUnit.assertEqual(target1.get("targetProperty"), model.item.get("seconds"));
    TKUnit.assertEqual(target2.get("targetProp"), newValue);
}

export function test_BindingToPropertiesWithSameNamesSecondCase() {
    const model = new DummyModel();
    model.item = new DummyClassWithSamePropertyNames();
    model.item.seconds = 1;
    const secondsobject = new DummyNestedClass();
    secondsobject.secondsobject = 1;
    model.item.secondsobject = secondsobject;

    const target1 = new Label();
    target1.bind({
        sourceProperty: "item.seconds",
        targetProperty: "targetProperty",
        twoWay: true
    }, model);

    const target2 = new Label();
    target2.bind({
        sourceProperty: "item.secondsobject.secondsobject",
        targetProperty: "targetProp",
        twoWay: true
    }, model);

    model.item.set("seconds", model.item.seconds + 1);
    let newValue = model.item.secondsobject.secondsobject + 1;
    model.item.set("secondsobject", { secondsobject: newValue });

    TKUnit.assertEqual(target1.get("targetProperty"), model.item.get("seconds"));
    TKUnit.assertEqual(target2.get("targetProp"), newValue);

    // calling this two times in order to ensure that adding and removing weak event listeners is working fine.
    newValue = model.item.secondsobject.secondsobject + 1;
    model.item.set("secondsobject", { secondsobject: newValue });

    TKUnit.assertEqual(target1.get("targetProperty"), model.item.get("seconds"));
    TKUnit.assertEqual(target2.get("targetProp"), newValue);
}

class RelatedPropsClass extends Observable {
    private _prop1: boolean;
    private _prop2: string;
    public get prop1(): boolean {
        return this._prop1;
    }
    public set prop1(value: boolean) {
        if (this._prop1 !== value) {
            this._prop1 = value;
            this.notifyPropertyChange("prop1", value);
        }
    }

    public get prop2(): string {
        this.prop1 = !this._prop1;
        this.notifyPropertyChange("prop2", this._prop2);

        return this._prop2;
    }

    public set prop2(value: string) {
        if (this._prop2 !== value) {
            this._prop2 = value;
            this.notifyPropertyChange("prop2", value);
        }
    }
}

export function test_BindingToRelatedProps() {
    let model = new RelatedPropsClass();
    model.prop1 = false;
    model.prop2 = "Alabala";

    let target1 = new Label();
    target1.bind({ sourceProperty: "prop1", targetProperty: "targetProp1" }, model);

    let target2 = new Label();
    target2.bind({ sourceProperty: "prop2", targetProperty: "targetProp2" }, model);

    model.prop2 = "Tralala";

    TKUnit.assertEqual(target2.get("targetProp2"), "Tralala");
}

export function test_only_Bindable_BindingContext_Null_DoesNotThrow() {
    const options: BindingOptions = {
        sourceProperty: "a.b",
        targetProperty: "text"
    };
    const obj = new Label();
    obj.bind(options);
    obj.bindingContext = fromObject({ a: "b" });
    obj.bindingContext = null;
}

export function test_Observable_from_nested_json_binds_correctly() {
    let expectedValue = "Test";
    let model = fromObjectRecursive({
        "firstObject": {
            "secondObject": {
                "dummyProperty": "text"
            }
        }
    });

    const obj = new Label();
    obj.bind({
        sourceProperty: "firstObject.secondObject.dummyProperty",
        targetProperty: "text"
    }, model);

    model.get("firstObject").get("secondObject").set("dummyProperty", expectedValue);

    TKUnit.assertEqual(obj.get("text"), expectedValue);
}

export function test_Observable_from_nested_json_binds_correctly_when_upper_object_is_changed() {
    let expectedValue = "Test";
    let model = fromObjectRecursive({
        "firstObject": {
            "secondObject": {
                "dummyProperty": "text"
            }
        }
    });

    const obj = new Label();
    obj.bind({
        sourceProperty: "firstObject.secondObject.dummyProperty",
        targetProperty: "text"
    }, model);

    model.get("firstObject").set("secondObject", fromObject({ "dummyProperty": expectedValue }));

    TKUnit.assertEqual(obj.get("text"), expectedValue);
}

export function test_BindingToBindingContextProperty_ShouldUseNewContext() {
    let stackLayout = new StackLayout();
    let label = new Label();
    stackLayout.addChild(label);

    label.bind({
        sourceProperty: "context",
        targetProperty: "bindingContext"
    });

    label.bind({
        sourceProperty: "text",
        targetProperty: "text"
    });

    let testBindingContext = fromObjectRecursive({
        context: {
            text: "Alabala"
        }
    });

    stackLayout.bindingContext = testBindingContext;

    (<any>testBindingContext).context.text = "Tralala";

    TKUnit.assertEqual(label.text, "Tralala");
}