typemoq

TypeMoq

Simple mocking library for JavaScript targeting TypeScript development. If you have used before a library like Moq then the syntax should look familiar, otherwise the examples below should hopefully provide enough information to get you started quickly.

Features

• Strongly typed
• Auto complete/intellisense support
• Control over mock behavior
• Mock both classes (with arguments) and objects
• Record and replay expectations
• Auto sandboxing for global classes and objects
• Supports ECMAScript 5 and 6
• Supports both browser and node.js runtimes

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Installing

npm install typemoq

Or if you use Bower:

bower install typemoq

Or add this NuGet dependency to your project:

PM> Install-Package typemoq 

The distribution directory should contain:

• Compiled JavaScript: typemoq.js and its minified version typemoq-min.js
• TypeScript definitions: typemoq.d.ts and typemoq.node.d.ts

Browser runtime

You need to include in your script file:

/// <reference path="./node_modules/typemoq/typemoq.d.ts" />

TypeMoq requires Underscore to run, so make sure to include it in your page along typemoq.js:

<script src="./node_modules/underscore/underscore.js"></script>
<script src="./node_modules/typemoq/typemoq.js"></script>

At this point you should have access in your script to a global variable named TypeMoq.

Node.js runtime

TypeScript 1.6 and later

import * as TypeMoq from "typemoq";

TypeScript pre 1.6

/// <reference path="./node_modules/typemoq/typemoq.d.ts" />

typemoq = require("typemoq");

Usage

After importing TypeMoq into your project, the following types should be available:

Type	Description
TypeMoq.Mock	Used for creating 'regular' mocks (see Create mocks and Setup mocks)
TypeMoq.MockBehavior	Used to specify how the mock should act when no expectations are defined (see Control mock behavior)
TypeMoq.It	Helper for matching arguments (see Setup mocks and Verify expectations)
TypeMoq.Times	Helper for performing verification (see Verify expectations)
TypeMoq.GlobalMock	Used to create 'global' mocks corresponding to global objects (see Create global mocks)
TypeMoq.GlobalScope	Used to create an execution context that makes use of any specified 'global' mocks (see Auto sandbox global mocks)
TypeMoq.MockException	Exception thrown internally containing debug info

### Create mocks

Mocks can be created either from class types and constructor arguments or from existing objects, including function objects.

Using class types and constructor arguments

// Using class as constructor parameter
let mock: TypeMoq.Mock<Bar> = TypeMoq.Mock.ofType(Bar);

// Using class as constructor parameter and casting result to interface
let mock: TypeMoq.Mock<IBar> = TypeMoq.Mock.ofType(Bar);

// Using interface as type variable and class as constructor parameter
let mock: TypeMoq.Mock<IBar> = TypeMoq.Mock.ofType<IBar>(Bar);

// Using class as constructor parameter and constructor arguments
let bar = new Bar();
let mock: TypeMoq.Mock<Foo> = TypeMoq.Mock.ofType(Foo, TypeMoq.MockBehavior.Loose, bar);

// Using a generic class as constructor parameter and constructor arguments
let mock: TypeMoq.Mock<GenericFoo<Bar>> = TypeMoq.Mock.ofType(GenericFoo, TypeMoq.MockBehavior.Loose, Bar, 999);

Using existing objects, including function objects

// From an existing object
let bar = new Bar();
let mock: TypeMoq.Mock<Bar> = TypeMoq.Mock.ofInstance(bar);

// Or from function objects
let mock1: TypeMoq.Mock<() => string> = TypeMoq.Mock.ofInstance(someFunc);
let mock2: TypeMoq.Mock<(a: any, b: any, c: any)=>string> = TypeMoq.Mock.ofInstance(someFuncWithArgs);

Note: Mocks (created in any of the ways listed above) expose the actual mock object through the .object property (that has the same type as the class or object being mocked).

### Setup mocks

Mocks allow to match functions, methods and properties and setup return callbacks or exceptions to throw.

Parameter matchers

Matcher	Description
TypeMoq.It.isValue<T>(x: T)	Performs deep comparison against the provided object or basic value
TypeMoq.It.isAny()	Matches any type
TypeMoq.It.isAnyObject<T>(x: Ctor<T>)	Matches any object compatible with the provided type
TypeMoq.It.isAnyString()	Matches any string
TypeMoq.It.isAnyNumber()	Matches any number
TypeMoq.It.is<T>(predicate: IFunc2<T, boolean>)	Performs comparison using the provided predicate

Matching functions

// Match a no args function
let mock: TypeMoq.Mock<() => string> = TypeMoq.Mock.ofInstance(someFunc);
mock.setup(x => x()).returns(() => "At vero eos et accusamus");

// Match a function with args
let mock: TypeMoq.Mock<(a: any, b: any, c: any) => string> = TypeMoq.Mock.ofInstance(someFuncWithArgs);
mock.setup(x => x(TypeMoq.It.isAny(), TypeMoq.It.isAny(), TypeMoq.It.isAny())).returns(() => "At vero eos et accusamus");

Matching methods

let mock = TypeMoq.Mock.ofType(Doer);

// Match a no args method
mock.setup(x => x.doNumber());

// Match a method with explicit number value params
mock.setup(x => x.doNumber(TypeMoq.It.isValue(321)));

// Match a method with implicit number value params
mock.setup(x => x.doNumber(321));

// Match a method with explicit string value params
mock.setup(x => x.doString(TypeMoq.It.isValue("abc")));

// Match a method with implicit string value params
mock.setup(x => x.doString("abc"));

// Match a method with object value params
let bar = new Bar();
mock.setup(x => x.doObject(TypeMoq.It.isAnyObject(Bar)));

// Match a method with any string params
mock.setup(x => x.doString(TypeMoq.It.isAnyString()));

// Match a method with any number params
mock.setup(x => x.doNumber(TypeMoq.It.isAnyNumber()));

// Match a method with any interface/class params
let bar1 = new Bar();
let bar2 = new Bar();
mock.setup(x => x.doBar(TypeMoq.It.isAnyObject(Bar)));

// Match a method by a param predicate 
let bar1 = new Bar();
bar1.value = "Ut enim ad minim veniam";
let bar2 = new Bar();
let mock = Mock.ofType(Doer);

mock.setup(x => x.doBar(It.is((x: Bar) => x.value === "Ut enim ad minim veniam"))).returns(() => bar2);

Matching properties

// Match a property getter
let mock = TypeMoq.Mock.ofType(FooWithPublicGetterAndSetter);
mock.setup(x => x.foo);

Attaching return callbacks

The callback attached to .returns has the same signature as the matching function/method.

Also the callback gets called with the arguments passed to the matching function/method and it must have the same return type, making possible the following:

mock.setup(x => x.doString("abc")).returns((s: string) => s.toUpperCase());

Attaching exceptions to throw

mock.setup(...).throws(new CustomException());

Attach callbacks

Attached callbacks are called before the .returns callback or .throws get called, and they have similar signature and behavior to .returns callbacks.

let mock = TypeMoq.Mock.ofType(Doer);
let called1, called2 = false;
let numberArg: number;

mock.setup(x => x.doString(TypeMoq.It.isAnyString())).callback(() => called1 = true).returns(s => s.toUpperCase());
mock.setup(x => x.doNumber(TypeMoq.It.isAnyNumber())).callback(n => { numberArg = n; called2 = true; }).returns(n => n + 1);

Record and replay

Mocks allow to "record" and "replay" one or more setups for the same matching function, method or property.

• If a single setup is recorded then at replay it is always executed:

let mock = TypeMoq.Mock.ofInstance(() => -1);

// record
mock.setup(x => x()).returns(() => 0);

// replay
expect(mock.object()).to.eq(0);
expect(mock.object()).to.eq(0);
expect(mock.object()).to.eq(0);

• If more setups are recorded then at replay they are executed in the order of registration:

let mock = TypeMoq.Mock.ofInstance(() => -1);

// record
mock.setup(x => x()).returns(() => 0);
mock.setup(x => x()).returns(() => 1);
mock.setup(x => x()).returns(() => 2);

// replay
expect(mock.object()).to.eq(0);
expect(mock.object()).to.eq(1);
expect(mock.object()).to.eq(2);
expect(mock.object()).to.eq(undefined);

In the latter case, when there are no more recorded setups left to play, the mock starts returning default values or raises MockException if MockBehavior.Strict (see Control mock behavior).

Reset mocks

Calling .reset() on a mock returns the mock to its initial state by removing any previous setups.

### Control mock behavior

Using MockBehavior

When creating a mock, you may specify a behavior value such as:

• MockBehavior.Loose (default) - never throws and returns default values
• MockBehavior.Strict - raises exceptions for anything that doesn't have a corresponding expectation

let mock = TypeMoq.Mock.ofType(Doer, TypeMoq.MockBehavior.Strict);

Calling the object being mocked

When the mock property callBase is set to true, if there's no overriding setup the mock invokes the object being mocked.

mock.callBase = true;

The default value of callBase is false, so by default when there's no overriding setup the mock returns undefined.

### Verify expectations

Expectations can be verified either one by one or all at once by marking matchers as verifiable.

Expectations

Expectation	Description
TypeMoq.Times.exactly(n: number)	Called exactly n times
TypeMoq.Times.never()	Never called
TypeMoq.Times.once()	Called once
TypeMoq.Times.atLeastOnce()	Called at least once
TypeMoq.Times.atMostOnce()	Called at most once

Verify expectations one by one

To verify an expectation you can use the verify method and specify a matching function and an expectation.

// Verify that a no args function was called at least once
let mock: TypeMoq.Mock<() => string> = TypeMoq.Mock.ofInstance(someFunc);
mock.object();
mock.verify(x => x(), TypeMoq.Times.atLeastOnce());

// Verify that a function with args was called at least once
let mock: TypeMoq.Mock<(a: any, b: any, c: any) => string> = TypeMoq.Mock.ofInstance(someFuncWithArgs);
mock.object(1, 2, 3);
mock.verify(x => x(TypeMoq.It.isAnyNumber(), TypeMoq.It.isAnyNumber(), TypeMoq.It.isAnyNumber()), TypeMoq.Times.atLeastOnce());

// Verify that no args method was called at least once
let mock = TypeMoq.Mock.ofType(Doer);
mock.object.doVoid();
mock.verify(x => x.doVoid(), TypeMoq.Times.atLeastOnce());

// Verify that method with params was called at least once
let mock = TypeMoq.Mock.ofType(Doer);
mock.object.doString("Lorem ipsum dolor sit amet");
mock.verify(x => x.doString(TypeMoq.It.isValue("Lorem ipsum dolor sit amet")), TypeMoq.Times.atLeastOnce());

// Verify that value getter was called at least once
let mock = TypeMoq.Mock.ofType(Bar);
mock.object.value;
mock.verify(x => x.value, TypeMoq.Times.atLeastOnce());

// Verify that value setter was called at least once
let mock = TypeMoq.Mock.ofType(Bar);
mock.object.value = "Lorem ipsum dolor sit amet";
mock.verify(x => x.value = TypeMoq.It.isValue("Lorem ipsum dolor sit amet"), TypeMoq.Times.atLeastOnce());

Note: When constructing a mock, it is allowed to pass mock objects as arguments and later verify expectations on them. E.g.:

let mockBar = TypeMoq.Mock.ofType(Bar);
let mockFoo = TypeMoq.Mock.ofType(Foo, TypeMoq.MockBehavior.Loose, mockBar.object);
mockFoo.callBase = true;

mockFoo.object.setBar("Lorem ipsum dolor sit amet");

mockBar.verify(x => x.value = TypeMoq.It.isValue("Lorem ipsum dolor sit amet"), TypeMoq.Times.atLeastOnce());

Verify all expectations at once

Instead of verifying one expectation at a time, you may specify the expectation at setup time by calling verifiable(times: Times) and then verifyAll() to check all expectations.

mock.setup(x => x.doNumber(999)).verifiable();
mock.setup(x => x.doString(It.isAny())).verifiable(Times.exactly(2));
mock.setup(x => x.doVoid()).verifiable(Times.atMostOnce());

mock.object.doVoid();
mock.object.doString("Lorem ipsum dolor sit amet");
mock.object.doString("Ut enim ad minim veniam");
mock.object.doNumber(999);

mock.verifyAll();

The default value of the times param is Times.atLeastOnce().

### Create global mocks

Global mocks are created by specifying a class type or an existing object, similar to regular mocks.

When creating mock instances out of global objects (such as window.localStorage), you should provide the name of the global object ("localStorage" in this case) as the second parameter.

You may also specify a container object for the type/object being mocked as the third parameter.

For browsers the top global object is the window object, which is the default container value in TypeMoq.GlobalMock. For node.js the top global object is the global object.

Using class types

// Create an instance using class as ctor parameter
let mock: TypeMoq.GlobalMock<GlobalBar> = TypeMoq.GlobalMock.ofType(GlobalBar, undefined, global);

// Create an instance using class as ctor parameter and casting result to interface
let mock: TypeMoq.GlobalMock<IGlobalBar> = TypeMoq.GlobalMock.ofType(GlobalBar, undefined, global);

// Create an instance using interface as type variable and class as ctor parameter
let mock: TypeMoq.GlobalMock<IGlobalBar> = TypeMoq.GlobalMock.ofType<IGlobalBar>(GlobalBar, undefined, global);

// Create an instance of 'XmlHttpRequest' global type
let mock = TypeMoq.GlobalMock.ofType(XMLHttpRequest, undefined, global);

Using existing objects, including function objects

// Create an instance using class as ctor parameter and ctor args
let bar = new Bar();
let foo = new Foo(bar);
let mock: TypeMoq.GlobalMock<Foo> = TypeMoq.GlobalMock.ofInstance(foo);

// Create an instance using a generic class as ctor parameter and ctor args
let foo = new GenericFoo(Bar);
let mock: TypeMoq.GlobalMock<GenericFoo<Bar>> = TypeMoq.GlobalMock.ofInstance(foo);

// Create an instance from an existing object
let bar = new GlobalBar();
let mock: TypeMoq.GlobalMock<GlobalBar> = TypeMoq.GlobalMock.ofInstance(bar);

// Create an instance from a function object
let mock1: TypeMoq.GlobalMock<() => string> = TypeMoq.GlobalMock.ofInstance(someGlobalFunc);
let mock2: TypeMoq.GlobalMock<(a: any, b: any, c: any) => string> = TypeMoq.GlobalMock.ofInstance(someGlobalFuncWithArgs);

// Create an instance from 'window.localStorage' global object
let mock = TypeMoq.GlobalMock.ofInstance(localStorage, "localStorage");

Note: Due to browser security limitations, global mocks created by specifying class type cannot have constructor arguments

### Auto sandbox global mocks

Replacing and restoring global class types and objects is done automagically by combining global mocks with global scopes.

// Global no args function is auto sandboxed
let mock = TypeMoq.GlobalMock.ofInstance(someGlobalFunc);
TypeMoq.GlobalScope.using(mock).with(() => {
    someGlobalFunc();
    someGlobalFunc();
});

// Global function with args is auto sandboxed
let mock = TypeMoq.GlobalMock.ofInstance(someGlobalFuncWithArgs);
TypeMoq.GlobalScope.using(mock).with(() => {
    someGlobalFuncWithArgs(1,2,3);
    someGlobalFuncWithArgs("1","2","3");
    someGlobalFuncWithArgs(1, 2, 3);
);

// Global object is auto sandboxed
let mock = TypeMoq.GlobalMock.ofType(GlobalBar);
TypeMoq.GlobalScope.using(mock).with(() => {
    let bar1 = new GlobalBar();
    bar1.value;
    bar1.value;
});

// 'window.XmlHttpRequest' global object is auto sandboxed
let mock = TypeMoq.GlobalMock.ofType(XMLHttpRequest);
TypeMoq.GlobalScope.using(mock).with(() => {
    let xhr1 = new XMLHttpRequest();
    xhr1.open("GET", "http://www.typescriptlang.org", true);
    xhr1.send();
    mock.verify(x => x.send(), TypeMoq.Times.exactly(1));
});
let xhr2 = new XMLHttpRequest();
xhr2.open("GET", "http://www.typescriptlang.org", true);
xhr2.send();
mock.verify(x => x.send(), TypeMoq.Times.exactly(1));

// 'window.localStorage' global object is auto sandboxed
let mock = TypeMoq.GlobalMock.ofInstance(localStorage, "localStorage");
mock.setup(x => x.getItem(TypeMoq.It.isAnyString())).returns((key: string) => "[]");
TypeMoq.GlobalScope.using(mock).with(() => {
    expect(localStorage.getItem("xyz")).to.eq("[]");
});
localStorage.setItem("xyz", "Lorem ipsum dolor sit amet");
expect(localStorage.getItem("xyz")).to.eq("Lorem ipsum dolor sit amet");

Note: Within a global scope, when constructing objects from global functions/class types which are being replaced by mocks, the constructor always returns the mocked object (of corresponding type) passed in as argument to the using function