Mock objects and protocols in iOS Swift - Interactive Code Practice

Practice - 5 Tasks

1fill in blank

easy

Complete the code to declare a protocol named Logger with a log function.

iOS Swift

protocol Logger {
    func [1](message: String)
}

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Awrite

Bprint

Csend

Dlog

Attempts:

3 left

💡 Hint

Common Mistakes

Using a function name that does not describe logging, like 'print' or 'send'.

The protocol requires a function named 'log' to handle logging messages.

2fill in blank

medium

Complete the code to create a mock class MockLogger that conforms to Logger protocol.

iOS Swift

class MockLogger: Logger {
    var messages: [String] = []
    func [1](message: String) {
        messages.append(message)
    }
}

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Asend

Bprint

Clog

Dwrite

Attempts:

3 left

💡 Hint

Common Mistakes

Using a different function name than the protocol requires.

The mock class must implement the 'log' function to conform to the Logger protocol.

3fill in blank

hard

Fix the error in the test function to verify the mock logger recorded the message.

iOS Swift

func testLogging() {
    let mockLogger = MockLogger()
    mockLogger.log(message: "Test message")
    assert(mockLogger.[1].count == 1)
}

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Amessages

BlogMessages

Clogs

Dmessage

Attempts:

3 left

💡 Hint

Common Mistakes

Using a property name that does not exist in MockLogger.

The mock logger stores logged messages in the 'messages' array.

4fill in blank

hard

Fill both blanks to create a protocol and a mock class that counts calls.

iOS Swift

protocol [1] {
    func fetchData()
}

class MockFetcher: [2] {
    var callCount = 0
    func fetchData() {
        callCount += 1
    }
}

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ADataFetcher

BLogger

CDataFetcher

DLogger

Attempts:

3 left

💡 Hint

Common Mistakes

Using mismatched protocol and class names.

The protocol is named DataFetcher and the mock class conforms to it to count calls.

5fill in blank

hard

Fill all three blanks to define a protocol, a mock class, and a test verifying call count.

iOS Swift

protocol [1] {
    func save(data: String)
}

class MockSaver: [2] {
    var saveCalls = 0
    func save(data: String) {
        saveCalls += 1
    }
}

func testSave() {
    let mock = MockSaver()
    mock.save(data: "Hello")
    assert(mock.[3] == 1)
}

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ASaver

BMockSaver

CsaveCalls

DSaver

Attempts:

3 left

💡 Hint

Common Mistakes

Using incorrect protocol or property names in the test.

The protocol is Saver, the mock class conforms to Saver, and the test checks saveCalls count.