Merge pull request #765 from albertache1998/list-lists

[KTLN-712] Initialize a List of Lists in Kotlin

Author: acerasoni

core-kotlin-modules/core-kotlin-collections-list-2/src/test/kotlin/listOfLists/ListOfListsUnitTest.kt

@@ -0,0 +1,46 @@
+package listOfLists
+
+import org.junit.jupiter.api.Assertions.assertEquals
+import org.junit.jupiter.api.Test
+import kotlin.test.assertTrue
+
+class ListOfListsUnitTest {
+
+    @Test
+    fun `Creates an immutable list of immutable lists using listOf()`() {
+        val listOfLists = listOf(listOf(1, 2), listOf(3, 4), listOf(5, 6))
+
+        assertEquals(3, listOfLists.size)
+        assertEquals(listOf(1, 2), listOfLists[0])
+        assertEquals(listOf(3, 4), listOfLists[1])
+        assertEquals(listOf(5, 6), listOfLists[2])
+    }
+
+    @Test
+    fun `Creates an immutable list of mutable lists using List constructor`() {
+        val listOfLists = List(3) { MutableList<Int>(2) {0} }
+
+        assertEquals(3, listOfLists.size)
+        assertEquals(listOf(0, 0), listOfLists[0])
+        assertEquals(listOf(0, 0), listOfLists[1])
+        assertEquals(listOf(0, 0), listOfLists[2])
+    }
+
+    @Test
+    fun `Creates an immutable list of immutable lists using map method`() {
+        val listOfLists = (0..2).map { _ -> (0..1).map { 0 } }
+
+        assertEquals(3, listOfLists.size)
+        assertEquals(listOf(0, 0), listOfLists[0])
+        assertEquals(listOf(0, 0), listOfLists[1])
+        assertEquals(listOf(0, 0), listOfLists[2])
+    }
+
+    @Test
+    fun `Creates an immutable list of mutable lists using map method`() {
+        val listOfMutableLists = (0..2).map { mutableListOf<Int>() }
+
+        assertEquals(3, listOfMutableLists.size)
+        assertTrue(listOfMutableLists.all { it.isEmpty() })
+    }
+}