MOQ .Net Mocking Framework Overview

MOQ Unit test Framework

Mocking is the ability to isolate code which will run in production with a test version so that external resource calls like database calls, web service calls can be mocked for easier unit testing.

Benefits of Mocking

1. Execution of tests becomes faster with mocking objects
2. Supports parallel development when the functionality is not yet developed or dependent on another team
3. Isolates specific components from the actual testing components

MockBehaviour

1. MockBehaviour.Strict - Using this type will throw an exception if the mocked method is not setup. All the methods of the mocked object need to be setup. There is a chance existing tests might fail if an object is strictly mocked.
2. MockBehaviour.Loose - Using this type will not throw an exception if all methods are not set up and hence fewer lines of code in our unit tests.
3. MockBehaviour.Default - By default, all mocked objects have a Default mock behaviour

Argument matching in mocked methods

1. It.Is<string>(number => number.StartsWith(‘x’)).Returns(true)
2. It.IsIn(“x”, “y”, “z”).Returns(true)
3. It.IsInRange(“a”,”z”, Range.IsInclusive).Returns(true)
4. It.IsRegex(“[a-z]”,RegexOptions.None).Returns(true)

Setup
_mockObject.Setup(x => x.Method(parameters)). Returns();
_mockObject.Setup(x => x.Method(parameters)). ReturnsAsync();
_mockObject.Setup(x => x.Method(parameters)). Returns(Task.FromResult<T> (response));

Exceptions
var exception = Record.ExceptionAsync( () => {call the method});
var exception = Assert.Throws<ExceptionType>( () => {call the method });
var exception = Assert.ThrowsAsync<ExceptionType>( () => {call the method });

Assert.NotNull(exception)
Assert.IsType<exceptiontype>(exception)
Assert.Single()
Assert.Equal()

Mocking IOptions - 
IOptions<T> options = Options.Create(new <T> { });

Setup for methods with out parameters - 

Bool isValid = true;

Mock.Setup(x => x.IsValid(It.IsAny<string>(), out IsValid);

Mocking Property

Mock.SetUp(x => x.LicenseKey). Returns(“EXPIRED”);

Tracking changes to MOQ properties

SetupProperty()

SetupAllProperties()

MOQ Verify

Mom.Verify(x => x.IsValid(paramter)) - o verify if a method was executed

Mom.Verify(x => x.IsValid(It.IsNotNull<string>()), “Error Message”); - To add custom failure message.

_mockObject.Verify(_ => _.Method(), Times.Once);
_mockObject.Verify(_ => _.Method(), Times. AtleastOnce);
_mockObject.Verify(_ => _.Method(), Times. Never);

Property verify

mock.VerifyGet(x => x.Property) 

mock.VerifyGet(x => x.Property, Times.Once)

mock.VerifySet(x => x.ValidMode = It.IsAny<ValidationMode>());

Advanced - 

Raising Events - Raise()

Setup.Returns()

          .Raises()

SetupSequence() - To set different results for the same setup

To Setup protected methods - 

Using Moq.Protected;

.Protected().Setup<>(method name, ItExpr.IsAny<>).Returns(true)

LINQ to Mocks - [Use this to Setup mocks]

IInterface mockobj = Mock.Of<IInterface>

(

      x = >

       x.Method().Setup == true

       x.Property.Setup == “OK”

)

Mocking Controller Context (httpcontext) - 
ControllerContext context = new ControllerContext();
context.HttpContext = new DefaultHttpContext();
context.HttpContext.Request.Headers.Add();
context.HttpContext.Request.Scheme = "https";
context.HttpContext.Request.Host = new HostString("localhost");
context.HttpContext.Connection.RemoteIpAddress = System.Net.IPAddress.Parse("xxx.0.0.1");
return context;

Mocking HttpContext - 
private readonly DefaultHttpContext _httpContext = new DefaultHttpContext();
private readonly Mock<IServiceProvider> _serviceProvideMock = new Mock<IServiceProvider>
_httpContext.RequestServices = _serviceProvideMock.Object;
_httpContext.Connection.RemoteIpAddress = System.Net.IPAddress.Parse("xxx.0.0.1");
_httpContext.Request.ContentLength = 123;
_httpContext.Request.Method = "Get";
_httpContext.Request.Scheme = "http";
_httpContext.Request.Path = "/path";
_httpContext.Request.Host = HostString.FromUriComponent("localhost");

Initialize Controller context - 
private ControllerContext _controllerContext;
var actionDescriptor = new ControllerActionDescriptor();
var routeData = new RouteData();
_controllerContext = new ControllerContext()
{ ActionDescriptor = actionDescriptor, HttpContext = httpContext, RouteData = routeData };
_controllerContext.ActionDescriptor.ControllerName = "Test";
_controllerContext.ActionDescriptor.ActionName = "Test";