Code Coverage of Companion Object in Android

Question

public class Util
{
    companion object {
        fun isPalindrome(num: Int): Boolean {
            var num = num
            var reversedInteger = 0
            var remainder: Int
            val originalInteger: Int = num
            while (num != 0) {
                remainder = num % 10
                reversedInteger = reversedInteger * 10 + remainder
                num /= 10
            }
            return originalInteger == reversedInteger
        }
    }
}


internal class UtilTest
{
    @Test
    fun is_palindrome_true() {
        val isPalindrome = isPalindrome(232)
        assertEquals(true,isPalindrome)
    }
    @Test
    fun is_palindrome_false() {
        val isPalindrome = isPalindrome(112)
        assertEquals(false,isPalindrome)
    }
}

Code coverage when using companion object is Method 50% (1/2) Class 50% (1/2) Line 88% (8/9)

And when I use the function as a Top Level Function the code coverage is 100% for all.

Why is it so ?

How can I increase coverage while using companion object?