Foq is an open source .Net mocking library with a familiar fluent API for Moq users that lets you setup mock object using either LINQ or F# Code Quotations. Moq was developed to take advantage of .Net 3.5 LINQ expression trees and C# 3.0 features. Foq has been designed to provide first-class support for users of both C# and F#. C# users can use the LINQ API while F# users can choose between the LINQ API and Code Quotations. We use F# as a unit testing language at work and Foq for mocking code written in both C# and F#.
Setup a mock method in C# with a lambda expression:
.SetupFunc(x => x.Contains(It.IsAny<int>())).Returns(true)
Setup a mock method in F# with a Code Quotation:
.Setup(fun x -> <@ x.Contains(any()) @>).Returns(true)
Setup a property in C# with a lambda expression:
.SetupPropertyGet(x => x.Count).Returns(1)
Setup multiple properties in C# with an anonymous object:
Price = 99.99M,
Quantity = 10,
Side = Side.Bid,
TimeInForce = TimeInForce.GoodTillCancel
Setup multiple members in F# with a Code Quotation:
Mock<IList<char>>.With(fun xs ->
<@ xs.Count --> 2
xs.Item(0) --> '0'
xs.Item(1) --> '1'
xs.Contains(any()) --> true
xs.RemoveAt(2) ==> System.ArgumentOutOfRangeException()
Verify a method was called in C#:
Mock.VerifyFunc(() => list.Contains(1));
Verify a method was called once in F#:
Mock.Verify(<@ xs.Contains(any()) @>, once)
Foq is available on Nuget or for F# projects you can just include the Foq.fs source file.