frugoman/swiftmocks

Usage

Mocking

To mock an object, simply add the @Mock attribute to your class. This will generate a mock property on your class that you can use to verify calls to the object.

// This is the class we want to mock
class MyObject {
    func doSomething() {}
}

@Mock
class MyObject {
    func doSomething() {
        mock.doSomething()
    }
    let mock = MyObjectMock() // generated
    class MyObjectMock { // generated
        var doSomethingCalls: Mock<Void, Void> = .init() // generated
        func doSomething() { // generated
            doSomethingCalls.record(()) // generated
        } // generated
    } // generated
}

Stubbing Return Values

To stub out return values, simply call the mockCall method on the mock property.

// This is the class we want to mock
class MyObject {
    func doSomething() -> Int { 
        mock.doSomething()
    }
}

@Mock
class MyObject {
    func doSomething() -> Int {
        mock.doSomething()
    }
}

let myObject = MyObject()
myObject.mock.doSomethingCalls.mockCall { 1 }

print(myObject.doSomething()) // this prints 1

Verifying Calls

To verify that a method was called, simply call the verify method on the mock property.

// This is the class we want to mock
class MyObject {
    func doSomething() {}
}

@Mock
class MyObject {
    func doSomething(param: Int) {
        mock.doSomething(param: param)
    }
}

let myObject = MyObject()
myObject.doSomething(param: 999)

XCTAssertEqual(myObject.mock.doSomethingCalls.callCount, 1)
XCTAssertEqual(myObject.mock.doSomethingCalls.lastCall?.0, 999)

Taking advantage in tests

In your production code, you'd define your protocols and classes as normal. In your tests, you'd add the @Mock to the Mock class, and then use the mock property to verify calls.

// production code
protocol Service {
    func doSomething() -> String 
}

class RealService: Service {
    func doSomething() -> String {
        return "yes!"// production code
    }
}

let service: Service = RealService()
let useCase = UseCase(service: service)
--------------------

// test code
@Mock
class MockService: Service {
    func doSomething() -> String {
        mock.doSomething()
    }
}

func test() {
    // Given
    let mockService = MockService()
    let sut = UseCase(service: mockService)
    mockService.mock.doSomethingCalls.mockCall { "no!" }

    // When
    let result = sut.doSomething()

    // Then
    XCTAssertEqual(result, "no!")
    XCTAssertEqual(mockService.mock.doSomethingCalls.callCount, 1)
}

Package Metadata

Repository: frugoman/swiftmocks

Default branch: main

README: README.md