Why testing ensures app reliability in Android Kotlin - Test Your Understanding

Practice - 5 Tasks

1fill in blank

easy

Complete the code to create a simple unit test function in Kotlin.

Android Kotlin

fun testAddition() {
    val result = 2 + 2
    assertEquals([1], result)
}

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

A5

B6

C4

D3

Attempts:

3 left

💡 Hint

Common Mistakes

Using the wrong expected value in assertEquals.

Forgetting to use assertEquals for comparison.

The test checks if 2 + 2 equals 4, which is the correct result.

2fill in blank

medium

Complete the code to launch an activity in an Android instrumented test.

Android Kotlin

val scenario = ActivityScenario.launch([1]::class.java)

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

AApplication

BMainActivity

CContext

DView

Attempts:

3 left

💡 Hint

Common Mistakes

Using Application or Context instead of an Activity class.

Using a view class instead of an activity.

ActivityScenario.launch requires the activity class to launch, here MainActivity.

3fill in blank

hard

Fix the error in the test assertion to check if a list contains a value.

Android Kotlin

assertTrue(myList.[1](5))

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

Acontains

Bhas

Cincludes

Dexists

Attempts:

3 left

💡 Hint

Common Mistakes

Using non-existent functions like has or includes.

Confusing Kotlin with JavaScript syntax.

The correct Kotlin function to check if a list contains an element is contains().

4fill in blank

hard

Fill both blanks to create a test that checks if a function throws an exception.

Android Kotlin

assertThrows<[1]> {
    myFunction([2])
}

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

AIllegalArgumentException

B5

C0

DNullPointerException

Attempts:

3 left

💡 Hint

Common Mistakes

Using the wrong exception type in assertThrows.

Passing a value that does not cause an exception.

The test expects an IllegalArgumentException when myFunction is called with 0.

5fill in blank

hard

Fill all three blanks to create a test that verifies a LiveData value changes correctly.

Android Kotlin

val liveData = MutableLiveData<Int>()
liveData.value = [1]
liveData.observeForever { value ->
    assertEquals([2], value)
}
liveData.value = [3]

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

A0

B1

Attempts:

3 left

💡 Hint

Common Mistakes

Not updating LiveData value before observing.

Expecting the wrong value in assertEquals.

The LiveData starts at 0, then changes to 1, and the observer checks for 1.