Introducing windowed() and chunked() (#9490)

core-kotlin-modules/core-kotlin-collections/src/test/kotlin/com/baeldung/collections/CollectionsTest.kt

@@ -1,5 +1,6 @@
 package com.baeldung.collections
 
+import org.assertj.core.api.Assertions.assertThat
 import org.junit.Test
 import kotlin.test.assertEquals
 import kotlin.test.assertFalse
@@ -143,4 +144,69 @@ class CollectionsTest {
         print(finalResult)
         assertEquals(1091, finalResult)
     }
+
+    @Test
+    fun whenApplyingChunked_thenShouldBreakTheCollection() {
+        val theList = listOf(1, 2, 3, 4, 5)
+        val chunked = theList.chunked(2)
+
+        assertThat(chunked.size).isEqualTo(3)
+        assertThat(chunked.first()).contains(1, 2)
+        assertThat(chunked[1]).contains(3, 4)
+        assertThat(chunked.last()).contains(5)
+    }
+
+    @Test
+    fun whenApplyingChunkedWithTransformation_thenShouldBreakTheCollection() {
+        val theList = listOf(1, 2, 3, 4, 5)
+        val chunked = theList.chunked(3) { it.joinToString(", ") }
+
+        assertThat(chunked.size).isEqualTo(2)
+        assertThat(chunked.first()).isEqualTo("1, 2, 3")
+        assertThat(chunked.last()).isEqualTo("4, 5")
+    }
+
+    @Test
+    fun whenApplyingWindowed_thenShouldCreateSlidingWindowsOfElements() {
+        val theList = (1..6).toList()
+        val windowed = theList.windowed(3)
+
+        assertThat(windowed.size).isEqualTo(4)
+        assertThat(windowed.first()).contains(1, 2, 3)
+        assertThat(windowed[1]).contains(2, 3, 4)
+        assertThat(windowed[2]).contains(3, 4, 5)
+        assertThat(windowed.last()).contains(4, 5, 6)
+    }
+
+    @Test
+    fun whenApplyingWindowedWithTwoSteps_thenShouldCreateSlidingWindowsOfElements() {
+        val theList = (1..6).toList()
+        val windowed = theList.windowed(size = 3, step = 2)
+
+        assertThat(windowed.size).isEqualTo(2)
+        assertThat(windowed.first()).contains(1, 2, 3)
+        assertThat(windowed.last()).contains(3, 4, 5)
+    }
+
+    @Test
+    fun whenApplyingPartialWindowedWithTwoSteps_thenShouldCreateSlidingWindowsOfElements() {
+        val theList = (1..6).toList()
+        val windowed = theList.windowed(size = 3, step = 2, partialWindows = true)
+
+        assertThat(windowed.size).isEqualTo(3)
+        assertThat(windowed.first()).contains(1, 2, 3)
+        assertThat(windowed[1]).contains(3, 4, 5)
+        assertThat(windowed.last()).contains(5, 6)
+    }
+
+    @Test
+    fun whenApplyingTransformingWindows_thenShouldCreateSlidingWindowsOfElements() {
+        val theList = (1..6).toList()
+        val windowed = theList.windowed(size = 3, step = 2, partialWindows = true) { it.joinToString(", ") }
+
+        assertThat(windowed.size).isEqualTo(3)
+        assertThat(windowed.first()).isEqualTo("1, 2, 3")
+        assertThat(windowed[1]).isEqualTo("3, 4, 5")
+        assertThat(windowed.last()).isEqualTo("5, 6")
+    }
 }