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Mock Extension Methods

Mocking extension methods with JustMock is no different than mocking a regular method.
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Mocking Extension Methods Overview

Extension methods are a special kind of static methods that are called as if they were instance methods on the extended type.

Mocking extension methods is similar to mocking any instance method. The only difference is that we don’t need a Mock.Create<T>() call to initialize the class for mocking as extension mocking is by default partial.

public static class FooExtensions 
{ 
    public static string Echo(this Foo foo, string value)
    {
        return value;
    }
}
 
...
 
[TestMethod]
public void ShouldAssertExtensionMethodMockingWithArguments()
{
    string expected = "bar";
 
    // ARRANGE
    var foo = new Foo();
 
    // Arranging: When the extension method foo.Echo() is called with any string argument, 
    //            it should return expected.
    Mock.Arrange(() => foo.Echo(Arg.IsAny<string>())).Returns(expected);
 
    // ACT
    string actual = foo.Echo("hello");
 
    // ASSERT
    Assert.AreEqual(expected, actual);
}

Mock extension methods documentation

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Mock Extension Methods

Mocking Extension Methods Overview

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