diff --git a/kotlin-libraries/build.gradle b/kotlin-libraries/build.gradle
index b244df34b0..afb92de49e 100644
--- a/kotlin-libraries/build.gradle
+++ b/kotlin-libraries/build.gradle
@@ -7,6 +7,7 @@ version '1.0-SNAPSHOT'
 buildscript {
     ext.kotlin_version = '1.2.41'
     ext.ktor_version = '0.9.2'
+    ext.khttp_version = '0.1.0'
 
     repositories {
         mavenCentral()
@@ -47,11 +48,16 @@ dependencies {
     compile "io.ktor:ktor-server-netty:$ktor_version"
     compile "ch.qos.logback:logback-classic:1.2.1"
     compile "io.ktor:ktor-gson:$ktor_version"
+    compile "khttp:khttp:$khttp_version"
     testCompile group: 'junit', name: 'junit', version: '4.12'
+    testCompile group: 'org.jetbrains.spek', name: 'spek-api', version: '1.1.5'
+    testCompile group: 'org.jetbrains.spek', name: 'spek-subject-extension', version: '1.1.5'
+    testCompile group: 'org.jetbrains.spek', name: 'spek-junit-platform-engine', version: '1.1.5'
     implementation 'com.beust:klaxon:3.0.1'
+    implementation 'io.reactivex.rxjava2:rxkotlin:2.3.0'
 
 }
 task runServer(type: JavaExec) {
     main = 'APIServer'
    classpath = sourceSets.main.runtimeClasspath
-}
\ No newline at end of file
+}
diff --git a/kotlin-libraries/pom.xml b/kotlin-libraries/pom.xml
index 3d2c7337b0..b75c77f358 100644
--- a/kotlin-libraries/pom.xml
+++ b/kotlin-libraries/pom.xml
@@ -166,6 +166,12 @@
             <version>2.6</version>
             <scope>compile</scope>
         </dependency>
+
+        <dependency>
+            <groupId>io.reactivex.rxjava2</groupId>
+            <artifactId>rxkotlin</artifactId>
+            <version>2.3.0</version>
+        </dependency>
     </dependencies>
 
     <properties>
diff --git a/kotlin-libraries/src/test/kotlin/com/baeldung/kotlin/rxkotlin/RxKotlinTest.kt b/kotlin-libraries/src/test/kotlin/com/baeldung/kotlin/rxkotlin/RxKotlinTest.kt
new file mode 100644
index 0000000000..979ed3f809
--- /dev/null
+++ b/kotlin-libraries/src/test/kotlin/com/baeldung/kotlin/rxkotlin/RxKotlinTest.kt
@@ -0,0 +1,157 @@
+package com.baeldung.kotlin.rxkotlin
+
+import io.reactivex.Maybe
+import io.reactivex.Observable
+import io.reactivex.functions.BiFunction
+import io.reactivex.rxkotlin.*
+import io.reactivex.subjects.PublishSubject
+import org.junit.Test
+import kotlin.test.assertEquals
+import kotlin.test.assertFalse
+
+class RxKotlinTest {
+
+    @Test
+    fun whenBooleanArrayToObserver_thenBooleanObserver() {
+        val observable = listOf(true, false, false).toObservable()
+        observable.test().assertValues(true, false, false)
+    }
+
+    @Test
+    fun whenBooleanArrayToFlowable_thenBooleanFlowable() {
+        val flowable = listOf(true, false, false).toFlowable()
+        flowable.buffer(2).test().assertValues(listOf(true, false), listOf(false))
+    }
+
+    @Test
+    fun whenIntArrayToObserver_thenIntObserver() {
+        val observable = listOf(1, 1, 2, 3).toObservable()
+        observable.test().assertValues(1, 1, 2, 3)
+    }
+
+    @Test
+    fun whenIntArrayToFlowable_thenIntFlowable() {
+        val flowable = listOf(1, 1, 2, 3).toFlowable()
+        flowable.buffer(2).test().assertValues(listOf(1, 1), listOf(2, 3))
+    }
+
+    @Test
+    fun whenObservablePairToMap_thenSingleNoDuplicates() {
+        val list = listOf(Pair("a", 1), Pair("b", 2), Pair("c", 3), Pair("a", 4))
+        val observable = list.toObservable()
+        val map = observable.toMap()
+        assertEquals(mapOf(Pair("a", 4), Pair("b", 2), Pair("c", 3)), map.blockingGet())
+    }
+
+    @Test
+    fun whenObservablePairToMap_thenSingleWithDuplicates() {
+        val list = listOf(Pair("a", 1), Pair("b", 2), Pair("c", 3), Pair("a", 4))
+        val observable = list.toObservable()
+        val map = observable.toMultimap()
+        assertEquals(
+                mapOf(Pair("a", listOf(1, 4)), Pair("b", listOf(2)), Pair("c", listOf(3))),
+                map.blockingGet())
+    }
+
+    @Test
+    fun whenMergeAll_thenStream() {
+        val subject = PublishSubject.create<Observable<String>>()
+        val observable = subject.mergeAll()
+        val testObserver = observable.test()
+        subject.onNext(Observable.just("first", "second"))
+        testObserver.assertValues("first", "second")
+        subject.onNext(Observable.just("third", "fourth"))
+        subject.onNext(Observable.just("fifth"))
+        testObserver.assertValues("first", "second", "third", "fourth", "fifth")
+    }
+
+    @Test
+    fun whenConcatAll_thenStream() {
+        val subject = PublishSubject.create<Observable<String>>()
+        val observable = subject.concatAll()
+        val testObserver = observable.test()
+        subject.onNext(Observable.just("first", "second"))
+        testObserver.assertValues("first", "second")
+        subject.onNext(Observable.just("third", "fourth"))
+        subject.onNext(Observable.just("fifth"))
+        testObserver.assertValues("first", "second", "third", "fourth", "fifth")
+    }
+
+    @Test
+    fun whenSwitchLatest_thenStream() {
+        val subject = PublishSubject.create<Observable<String>>()
+        val observable = subject.switchLatest()
+        val testObserver = observable.test()
+        subject.onNext(Observable.just("first", "second"))
+        testObserver.assertValues("first", "second")
+        subject.onNext(Observable.just("third", "fourth"))
+        subject.onNext(Observable.just("fifth"))
+        testObserver.assertValues("first", "second", "third", "fourth", "fifth")
+    }
+
+    @Test
+    fun whenMergeAllMaybes_thenObservable() {
+        val subject = PublishSubject.create<Maybe<Int>>()
+        val observable = subject.mergeAllMaybes()
+        val testObserver = observable.test()
+        subject.onNext(Maybe.just(1))
+        subject.onNext(Maybe.just(2))
+        subject.onNext(Maybe.empty())
+        testObserver.assertValues(1, 2)
+        subject.onNext(Maybe.error(Exception("")))
+        subject.onNext(Maybe.just(3))
+        testObserver.assertValues(1, 2).assertError(Exception::class.java)
+    }
+
+    @Test
+    fun whenMerge_thenStream() {
+        val observables = mutableListOf(Observable.just("first", "second"))
+        val observable = observables.merge()
+        observables.add(Observable.just("third", "fourth"))
+        observables.add(Observable.error(Exception("e")))
+        observables.add(Observable.just("fifth"))
+
+        observable.test().assertValues("first", "second", "third", "fourth").assertError(Exception::class.java)
+    }
+
+    @Test
+    fun whenMergeDelayError_thenStream() {
+        val observables = mutableListOf<Observable<String>>(Observable.error(Exception("e1")))
+        val observable = observables.mergeDelayError()
+        observables.add(Observable.just("1", "2"))
+        observables.add(Observable.error(Exception("e2")))
+        observables.add(Observable.just("3"))
+
+        observable.test().assertValues("1", "2", "3").assertError(Exception::class.java)
+    }
+
+    @Test
+    fun whenCast_thenUniformType() {
+        val observable = Observable.just<Number>(1, 1, 2, 3)
+        observable.cast<Int>().test().assertValues(1, 1, 2, 3)
+    }
+
+    @Test
+    fun whenOfType_thenFilter() {
+        val observable = Observable.just(1, "and", 2, "and")
+        observable.ofType<Int>().test().assertValues(1, 2)
+    }
+
+    @Test
+    fun whenFunction_thenCompletable() {
+        var value = 0
+        val completable = { value = 3 }.toCompletable()
+        assertFalse(completable.test().isCancelled)
+        assertEquals(3, value)
+    }
+
+    @Test
+    fun whenHelper_thenMoreIdiomaticKotlin() {
+        val zipWith = Observable.just(1).zipWith(Observable.just(2)) { a, b -> a + b }
+        zipWith.subscribeBy(onNext = { println(it) })
+        val zip = Observables.zip(Observable.just(1), Observable.just(2)) { a, b -> a + b }
+        zip.subscribeBy(onNext = { println(it) })
+        val zipOrig = Observable.zip(Observable.just(1), Observable.just(2), BiFunction<Int, Int, Int> { a, b -> a + b })
+        zipOrig.subscribeBy(onNext = { println(it) })
+    }
+}
diff --git a/rule-engines/easy-rules/pom.xml b/rule-engines/easy-rules/pom.xml
index 5b88ce4e94..369451c56c 100644
--- a/rule-engines/easy-rules/pom.xml
+++ b/rule-engines/easy-rules/pom.xml
@@ -10,6 +10,7 @@
         <groupId>com.baeldung</groupId>
         <artifactId>parent-modules</artifactId>
         <version>1.0.0-SNAPSHOT</version>
+        <relativePath>../..</relativePath>
     </parent>
 
     <dependencies>
@@ -23,4 +24,4 @@
     <properties>
         <easy-rules.version>3.0.0</easy-rules.version>
     </properties>
-</project>
\ No newline at end of file
+</project>
diff --git a/rule-engines/openl-tablets/pom.xml b/rule-engines/openl-tablets/pom.xml
index 3bd6055fc9..b19ec8d3f1 100644
--- a/rule-engines/openl-tablets/pom.xml
+++ b/rule-engines/openl-tablets/pom.xml
@@ -10,6 +10,7 @@
         <groupId>com.baeldung</groupId>
         <artifactId>parent-modules</artifactId>
         <version>1.0.0-SNAPSHOT</version>
+        <relativePath>../..</relativePath>
     </parent>
 
     <dependencies>
@@ -29,4 +30,4 @@
         <openl.version>5.19.4</openl.version>
     </properties>
 
-</project>
\ No newline at end of file
+</project>
diff --git a/rule-engines/rulebook/pom.xml b/rule-engines/rulebook/pom.xml
index 90b5e55417..5e0b900bd9 100644
--- a/rule-engines/rulebook/pom.xml
+++ b/rule-engines/rulebook/pom.xml
@@ -10,6 +10,7 @@
         <groupId>com.baeldung</groupId>
         <artifactId>parent-modules</artifactId>
         <version>1.0.0-SNAPSHOT</version>
+        <relativePath>../..</relativePath>
     </parent>
 
     <dependencies>
@@ -24,4 +25,4 @@
         <rulebook.version>0.6.2</rulebook.version>
     </properties>
 
-</project>
\ No newline at end of file
+</project>