Unit testing with JUnit in Android Kotlin - Interactive Code Practice

Practice - 5 Tasks

1fill in blank

easy

Complete the code to create a basic JUnit test function in Kotlin.

Android Kotlin

import org.junit.Test
import org.junit.Assert.*

class CalculatorTest {
  @Test
  fun testAddition() {
    val result = 2 + 3
    assertEquals(5, result[1])
  }
}

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

A)

B]

C}

D;

Attempts:

3 left

💡 Hint

Common Mistakes

Using a bracket or brace instead of a parenthesis to close the function call.

Adding a semicolon which is not needed in Kotlin.

The assertEquals function call must be properly closed with a parenthesis ")".

2fill in blank

medium

Complete the code to import the JUnit Assert class correctly.

Android Kotlin

import org.junit.[1].*

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

AAssert

BTest

CAssertions

DRule

Attempts:

3 left

💡 Hint

Common Mistakes

Importing Test instead of Assert, which only provides the @Test annotation.

Using Assertions which is from JUnit 5, but here we use JUnit 4 style.

The Assert class contains the assertion methods like assertEquals used in tests.

3fill in blank

hard

Fix the error in the test function annotation to make it a valid JUnit test.

Android Kotlin

class SampleTest {
  @[1]
  fun sampleTest() {
    assertTrue(true)
  }
}

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

ATestCase

Btest

CTest

DTestFunction

Attempts:

3 left

💡 Hint

Common Mistakes

Using lowercase @test which is not recognized by JUnit.

Using @TestCase or @TestFunction which do not exist.

The correct annotation to mark a function as a JUnit test is @Test with capital T.

4fill in blank

hard

Complete the code to write an assertion that checks if two strings are equal.

Android Kotlin

class StringTest {
  @Test
  fun testStrings() {
    val expected = "hello"
    val actual = "hello"
    assert[1](expected, actual)
  }
}

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

AEquals

BEqualsIgnoreCase

C)

D]

Attempts:

3 left

💡 Hint

Common Mistakes

Using assertEqualsIgnoreCase which does not exist in JUnit.

Closing the call with a bracket instead of a parenthesis.

The assertion method is assertEquals and it must be closed with a parenthesis.

5fill in blank

hard

Fill all three blanks to write a test that checks if a list contains a specific element.

Android Kotlin

class ListTest {
  @Test
  fun testContains() {
    val items = listOf("apple", "banana", "cherry")
    assertTrue(items.[1]("banana") [2] [3])
  }
}

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

Acontains

B==

Ctrue

Dequals

Attempts:

3 left

💡 Hint

Common Mistakes

Using equals instead of contains to check list membership.

Not comparing the result to true, which is needed for assertTrue.

The list method contains checks if an element is present, and assertTrue expects a boolean expression, so we check if items.contains("banana") == true.