LiveData Arraylist casting error

[abhijeetraahi]

Getting these error while trying to mock the LiveData object below code is in my class
ViewModelClass -
private val _departmentDropDownList = MutableLiveData<List?>()
val departmentDropDownList: LiveData<List?> = _departmentDropDownList
TestClass -
mockViewModel = declareMock {
when(this.showProgressBar).thenReturn(MutableLiveData(false))
when(this.departmentDropDownList).thenReturn(MutableLiveData(null))
when(this.selectedCompareType).thenReturn("")
val itemList = context.resources.getStringArray(R.array.comparison_type)
when(this.getComparisonDropDownList(itemList)).thenReturn(getItemList(itemList))
}

Error which i am getting -
class java.util.ArrayList cannot be cast to class androidx.lifecycle.LiveData (java.util.ArrayList is in module java.base of loader 'bootstrap'; androidx.lifecycle.LiveData is in unnamed module of loader org.robolectric.internal.AndroidSandbox$SdkSandboxClassLoader @4da9f723)
java.lang.ClassCastException: class java.util.ArrayList cannot be cast to class androidx.lifecycle.LiveData (java.util.ArrayList is in module java.base of loader 'bootstrap'; androidx.lifecycle.LiveData is in unnamed module of loader org.robolectric.internal.AndroidSandbox$SdkSandboxClassLoader @4da9f723)