sequences in kotlin (#8515)

* sequences in kotlin

* fix readme

* fix naming

* fix naming

core-kotlin-2/src/test/kotlin/com/baeldung/sequences/SequencesTest.kt

@@ -0,0 +1,54 @@
+package com.baeldung.sequeces
+
+import org.junit.Test
+import kotlin.test.assertEquals
+import java.time.Instant
+
+class SequencesTest {
+
+    @Test
+    fun shouldBuildSequenceWhenUsingFromElements() {
+        val seqOfElements = sequenceOf("first" ,"second", "third")
+                .toList()
+        assertEquals(3, seqOfElements.count())
+    }
+
+    @Test
+    fun shouldBuildSequenceWhenUsingFromFunction() {
+        val seqFromFunction = generateSequence(Instant.now()) {it.plusSeconds(1)}
+                .take(3)
+                .toList()
+        assertEquals(3, seqFromFunction.count())
+    }
+
+    @Test
+    fun shouldBuildSequenceWhenUsingFromChunks() {
+        val seqFromChunks = sequence {
+            yield(1)
+            yieldAll((2..5).toList())
+        }.toList()
+        assertEquals(5, seqFromChunks.count())
+    }
+
+    @Test
+    fun shouldBuildSequenceWhenUsingFromCollection() {
+        val seqFromIterable = (1..10)
+                .asSequence()
+                .toList()
+        assertEquals(10, seqFromIterable.count())
+    }
+
+    @Test
+    fun shouldShowNoCountDiffWhenUsingWithAndWithoutSequence() {
+        val withSequence = (1..10).asSequence()
+                .filter{it % 2 == 1}
+                .map { it * 2 }
+                .toList()
+        val withoutSequence = (1..10)
+                .filter{it % 2 == 1}
+                .map { it * 2 }
+                .toList()
+        assertEquals(withSequence.count(), withoutSequence.count())
+    }
+
+}