Why testing ensures app quality in iOS Swift - Test Your Understanding

Practice - 5 Tasks

1fill in blank

easy

Complete the code to create a simple unit test method in Swift.

iOS Swift

func testExample() {
    let result = 2 + 2
    XCTAssertEqual(result, [1])
}

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

A3

B5

C4

D22

Attempts:

3 left

💡 Hint

Common Mistakes

Using the wrong expected value like 3 or 5.

Confusing the actual result with the expected value.

The test checks if 2 + 2 equals 4, so the expected value is 4.

2fill in blank

medium

Complete the code to launch the app and check if a button exists in UI testing.

iOS Swift

let app = XCUIApplication()
app.launch()
let button = app.buttons["Submit"]
XCTAssertTrue(button.[1])

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

AisHidden

Bexists

CisEnabled

DisSelected

Attempts:

3 left

💡 Hint

Common Mistakes

Using 'isHidden' which checks visibility, not presence.

Using 'isEnabled' which checks if the button can be tapped.

To verify the button is present, we check if it exists.

3fill in blank

hard

Fix the error in the test assertion to correctly check if a label's text equals "Hello".

iOS Swift

let label = app.staticTexts["greetingLabel"]
XCTAssertEqual(label.[1], "Hello")

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Avalue

BlabelText

Clabel

Dtext

Attempts:

3 left

💡 Hint

Common Mistakes

Using 'text' which is not a valid property in XCUIElement.

Using 'label' which is a property but not the text content.

In UI tests, the label's text is accessed via the 'value' property.

4fill in blank

hard

Fill both blanks to create a test that waits for a button to appear before tapping it.

iOS Swift

let app = XCUIApplication()
let button = app.buttons["Continue"]
let exists = NSPredicate(format: "[1] == true")
expectation(for: exists, evaluatedWith: button, handler: nil)
waitForExpectations(timeout: [2], handler: nil)
button.tap()

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Aexists

BisEnabled

C5

D10

Attempts:

3 left

💡 Hint

Common Mistakes

Using 'isEnabled' instead of 'exists' in the predicate.

Setting the timeout too low or too high.

We wait for the button's 'exists' property to be true, with a timeout of 10 seconds.

5fill in blank

hard

Fill all three blanks to write a unit test that checks if a function returns true for valid input.

iOS Swift

func testIsValid() {
    let input = "[e-mail]"
    let result = Validator.[1](input: input)
    XCTAssert[2](result)
    XCTAssertFalse(Validator.[3](input: ""))
}

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

AisValidEmail

BTrue

DFalse

Attempts:

3 left

💡 Hint

Common Mistakes

Using XCTAssertFalse for the valid input check.

Mixing up function names.

The test calls 'isValidEmail' to check the input, asserts true for valid input, and false for empty input.