Product Perfect

KIF (Knowledge Interchange Format) is a computer-oriented language designed for the interchange of knowledge among disparate programs. It has declarative semantics and is based on first-order logic. KIF serves as an interchange format, allowing various systems to communicate and share information, regardless of their internal representation structures. The language allows for the representation of knowledge about objects, functions, relations and other entities in a machine-interpretable form. It was developed by the Stanford Logic Group and Genesereth at Stanford University in 1992 as part of DARPA's Knowledge Sharing Effort project.

Ask the right questions secure the right KIF talent among an increasingly shrinking pool of talent.

First 20 minutes

General KIF app knowledge and experience

The first 20 minutes of the interview should seek to understand the candidate's general background in KIF application development, including their experience with various programming languages, databases, and their approach to designing scalable and maintainable systems.

How would you setup KIF for a project?

First, KIF is added to the project either through CocoaPods, Carthage or manually. Then, a new UI Testing target is created. KIF is then imported into the test classes and you can start writing KIF tests.

What are the steps to write a simple KIF test?

First, you define a test case that subclasses KIFTestCase. Then, within this test case, you define a test method. Inside this method, you use KIF's tester() function to simulate user interactions and assert certain conditions.

Describe the difference between KIF and XCTest?

KIF and XCTest are both testing frameworks but they have different uses. XCTest is Apple's native testing framework that supports unit, performance, and UI testing. KIF, on the other hand, is specifically built for UI testing and provides a more comprehensive API for simulating user interactions.

How would you handle testing asynchronous operations with KIF?

KIF provides a waitFor... family of methods that can be used to wait for certain conditions to be met. These methods repeatedly evaluate a given condition until it's met or a timeout occurs, which is useful for testing asynchronous operations.

What are some common assertions you can make with KIF?

KIF provides a variety of assertions, such as asserting that a view with a certain accessibility label exists, that a view with a certain label is visible, or that a certain element is focused.

The hiring guide has been successfully sent to your email address.

Oops! Something went wrong while submitting the form.

What you’re looking for early on

Does the candidate demonstrate a strong understanding of KIF?

Has the candidate shown they can work well in a team?

Does the candidate have experience with test-driven development?

Is the candidate able to problem-solve effectively?

Next 20 minutes

Specific KIF development questions

The next 20 minutes of the interview should focus on the candidate's expertise with specific backend frameworks, their understanding of RESTful APIs, and their experience in handling data storage and retrieval efficiently.

How would you simulate a user tapping a button with KIF?

You can simulate a user tapping a button by calling the tapView(withAccessibilityLabel:) method on the KIF test actor, passing in the accessibility label of the button.

Describe the difference between tapView(withAccessibilityLabel:) and tapScreen(at:) in KIF?

tapView(withAccessibilityLabel:) finds a view with the given accessibility label and simulates a tap on it. tapScreen(at:) simulates a tap at a specific point on the screen, regardless of what view is at that location.

How would you simulate a user entering text into a text field with KIF?

You can simulate a user entering text into a text field by calling the enterText(:intoViewWithAccessibilityLabel:) method on the KIF test actor, passing in the text and the accessibility label of the text field.

What are some ways to debug failing KIF tests?

You can use the standard debugging tools in Xcode, such as breakpoints and the debugger console. Additionally, KIF provides detailed error messages when tests fail, which can help pinpoint the issue.

How would you test a custom gesture with KIF?

KIF doesn't support custom gestures out of the box, but you can extend it by subclassing KIFTestCase and adding your own methods for simulating your custom gestures.

The hiring guide has been successfully sent to your email address.

Oops! Something went wrong while submitting the form.

At this point, a skilled KIF engineer should demonstrate strong problem-solving abilities, proficiency in KIF programming language, and knowledge of software development methodologies. Red flags include lack of hands-on experience, inability to articulate complex concepts, or unfamiliarity with standard coding practices.

Digging deeper

Code questions

These will help you see the candidate's real-world development capabilities with KIF.

What does this simple KIF test case do?
func testExample() {
  viewTester().usingIdentifier('testView').tap()
}
This code is a simple KIF test case that finds a view with the identifier 'testView' and simulates a tap gesture on it.
What does this KIF code snippet do?
func testExample() {
  viewTester().usingIdentifier('testView').waitForView()
}
This code waits for a view with the identifier 'testView' to appear in the view hierarchy. If the view does not appear within a certain timeout, the test will fail.
What will be the output of this KIF code snippet?
func testExample() {
  viewTester().usingIdentifier('testView').waitForTappableView()
}
This code waits for a view with the identifier 'testView' to appear in the view hierarchy and be tappable. If the view does not become tappable within a certain timeout, the test will fail.
What does this KIF code snippet do?
func testExample() {
  viewTester().usingIdentifier('testView').waitForAbsence()
}
This code waits for a view with the identifier 'testView' to be removed from the view hierarchy. If the view does not disappear within a certain timeout, the test will fail.

Wrap-up questions

Final candidate for KIF Developer role questions

The final few questions should evaluate the candidate's teamwork, communication, and problem-solving skills. Additionally, assess their knowledge of microservices architecture, serverless computing, and how they handle KIF application deployments. Inquire about their experience in handling system failures and their approach to debugging and troubleshooting.

Describe the difference between using KIF and Apple's native UI testing framework?

While both can be used for UI testing, KIF provides a more comprehensive API for simulating user interactions. Additionally, KIF tests run in the same process as the app, which allows for more control and better performance.

How would you simulate a swipe gesture with KIF?

You can simulate a swipe gesture by calling one of the swipeView(withAccessibilityLabel:inDirection:) methods on the KIF test actor, passing in the accessibility label of the view to swipe and the direction of the swipe.

What are the limitations of KIF?

Some limitations of KIF include the lack of support for testing push notifications, limited support for testing interactions with system views like alerts and action sheets, and the inability to test the app when it's in the background.

KIF application related

Product Perfect's KIF development capabilities

Beyond hiring for your KIF engineering team, you may be in the market for additional help. Product Perfect provides seasoned expertise in KIF projects, and can engage in multiple capacities.

KIF Consultive assessments

KIF Application Conversion Assessment KIF Application Integration Assessment KIF Data & Database Integration Assessment

Custom KIF development projects

Custom KIF App Conversion KIF Custom App Development Process App UI Design for KIF Facelifts

Hiring guide for KIF Engineers

KIF Developer Hiring Guide

What you’re looking for early on

The ideal back-end app developer

What you’re looking to see on the KIF engineer at this point.

KIF Consultive assessments

Custom KIF development projects