Kotlin test assertions - Mini Project: Build & Apply

Kotlin test assertions

📖 Scenario: You are writing simple tests to check if your Kotlin functions work correctly. Testing helps you catch mistakes early, like checking if a calculator gives the right answer.

🎯 Goal: Build a Kotlin program that uses test assertions to verify the results of simple functions.

📋 What You'll Learn

Create a function that returns the sum of two numbers

Create a function that returns the product of two numbers

Write assertions to check if these functions return expected results

Print a message if all tests pass

💡 Why This Matters

🌍 Real World

Testing small functions helps ensure your code works correctly before using it in bigger programs.

💼 Career

Writing and understanding test assertions is a key skill for software developers to maintain code quality.

1

Create sum and product functions

Write a Kotlin function called sum that takes two Int parameters named a and b and returns their sum. Also write a function called product that takes two Int parameters named a and b and returns their product.

Kotlin

// Your code here

Need a hint?

Define two functions with the exact names sum and product. Each should take two integers and return an integer.

2

Set expected test results

Create two val variables named expectedSum and expectedProduct. Set expectedSum to 7 and expectedProduct to 12.

Kotlin

fun sum(a: Int, b: Int): Int {
    return a + b
}

fun product(a: Int, b: Int): Int {
    return a * b
}

// Your code here

Need a hint?

Use val to create constants for the expected results.

3

Write assertions to test functions

Write two assert statements. The first should check if sum(3, 4) equals expectedSum. The second should check if product(3, 4) equals expectedProduct.

Kotlin

fun sum(a: Int, b: Int): Int {
    return a + b
}

fun product(a: Int, b: Int): Int {
    return a * b
}

val expectedSum = 7
val expectedProduct = 12

// Your code here

Need a hint?

Use assert(condition) to check if the function results match the expected values.

4

Print success message

Write a println statement that prints "All tests passed!".

Kotlin

fun sum(a: Int, b: Int): Int {
    return a + b
}

fun product(a: Int, b: Int): Int {
    return a * b
}

val expectedSum = 7
val expectedProduct = 12

assert(sum(3, 4) == expectedSum)
assert(product(3, 4) == expectedProduct)

// Your code here

Need a hint?

Use println("All tests passed!") to show the success message.