Test-driven development in Swift in iOS Swift - Interactive Code Practice

Practice - 5 Tasks

1fill in blank

easy

Complete the code to declare a test case class in Swift.

iOS Swift

import XCTest

class [1]: XCTestCase {
}

Drag options to blanks, or click blank then click option'

AUnitTest

BMyTestCase

CTestClass

DTestCase

Attempts:

3 left

💡 Hint

Common Mistakes

Using a class name that does not inherit from XCTestCase

Forgetting to import XCTest

The test case class must inherit from XCTestCase. Naming it MyTestCase is a common convention.

2fill in blank

medium

Complete the code to write a test method that checks if 2 + 2 equals 4.

iOS Swift

func testAddition() {
    XCTAssertEqual([1], 4)
}

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A2 + 2

B1 + 2

C2 + 3

D3 + 3

Attempts:

3 left

💡 Hint

Common Mistakes

Using an expression that does not equal 4

Forgetting to use XCTAssertEqual

The test checks if 2 + 2 equals 4. This is a simple assertion example.

3fill in blank

hard

Fix the error in the test method declaration to make it a valid test method in Swift.

iOS Swift

func [1]() {
    XCTAssertTrue(true)
}

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ATestMethod

BverifyMethod

CcheckMethod

DtestMethod

Attempts:

3 left

💡 Hint

Common Mistakes

Starting method name with uppercase 'Test'

Using names that do not start with 'test'

Test methods must start with test in lowercase to be recognized by XCTest.

4fill in blank

hard

Fill both blanks to create a test that fails if the value is not nil.

iOS Swift

func testValueIsNil() {
    let value: String? = nil
    XCTAssert[1](value [2] nil)
}

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ATrue

B==

C!=

DEqual

Attempts:

3 left

💡 Hint

Common Mistakes

Using XCTAssertEqual instead of XCTAssertTrue

Using '!=' instead of '==' for nil comparison

XCTAssertTrue checks if a value is nil. The comparison uses == nil to confirm the value is nil.

5fill in blank

hard

Fill all three blanks to write a test that verifies a function returns true for positive numbers.

iOS Swift

func testIsPositive() {
    let number = 5
    let result = isPositive([1])
    XCTAssert[2](result == [3])
}

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Anumber

BTrue

Ctrue

Dnumber + 1

Attempts:

3 left

💡 Hint

Common Mistakes

Passing an incorrect argument to the function

Using XCTAssertFalse instead of XCTAssertTrue

Using uppercase 'True' instead of lowercase 'true'

The function isPositive is called with number. The test asserts the result is true using XCTAssertTrue.