Delegates

Mockolate supports mocking delegates including Action, Func<T>, and custom delegates.

Setup

Use sut.Mock.Setup(…) to configure delegate behavior.

// Mock Action delegate
Action myAction = Action.CreateMock();
myAction.Mock.Setup().Do(() => Console.WriteLine("Action invoked!"));

// Mock Func<T> delegate
Func<int> myFunc = Func<int>.CreateMock();
myFunc.Mock.Setup().Returns(42);

For custom delegates with parameters:

// Define a custom delegate (typically declared at type level)
public delegate int Calculate(int x, string operation);

// Create and setup the mock
Calculate calculator = Calculate.CreateMock();
calculator.Mock.Setup(It.IsAny<int>(), It.Is("add"))
    .Returns((x, operation) => x + 10);

Delegates with ref and out parameters are also supported:

// Define a custom delegate (typically declared at type level)
public delegate void ProcessData(int input, ref int value, out int result);

// Create and setup the mock
ProcessData processor = ProcessData.CreateMock();
processor.Mock.Setup(It.IsAny<int>(), It.IsRef<int>(v => v + 1), It.IsOut(() => 100));

• Use .Do(…) to run code when the delegate is invoked.
• Use .Returns(…) to specify the return value for Func<T> delegates.
• Use .Throws(…) to specify an exception to throw.
• Use .Returns(…) and .Throws(…) repeatedly to define a sequence of behaviors.
• Full parameter matching support for delegate parameters including ref and out parameters.

Verification

You can verify that delegates were invoked with specific arguments:

// Verify Action was invoked at least once
Action myAction = Action.CreateMock();
myAction.Invoke();
myAction.Mock.Verify().AtLeastOnce();

// Verify Func<T> was invoked exactly once
Func<int> myFunc = Func<int>.CreateMock();
_ = myFunc();
myFunc.Mock.Verify().Once();

For custom delegates with parameters:

// Define a custom delegate (typically declared at type level)
public delegate int Calculate(int x, string operation);

// Create, invoke, and verify the mock
Calculate calculator = Calculate.CreateMock();
_ = calculator(5, "add");
calculator.Mock.Verify(It.IsAny<int>(), It.Is("add")).Once();

Delegates with ref and out parameters are also supported:

// Define a custom delegate (typically declared at type level)
public delegate void ProcessData(int input, ref int value, out int result);

// Create, invoke, and verify the mock
ProcessData processor = ProcessData.CreateMock();
int val = 0;
processor(1, ref val, out int res);
processor.Mock.Verify(It.IsAny<int>(), It.IsRef<int>(), It.IsOut<int>()).Once();

Note:
Delegate parameters also support argument matchers.