Introduced jUnit5, migrated Abstract Factory and Adapter to jUnit, updated Adapter

Author: dbacinski

build.gradle

@@ -1,4 +1,3 @@
-group 'pl.dariuszbacinski.designpatterns'
 version '1.0-SNAPSHOT'
 
 buildscript {
@@ -21,4 +20,20 @@ repositories {
 dependencies {
     implementation("org.jetbrains.kotlin:kotlin-stdlib-jdk8")
     implementation("org.jetbrains.kotlin:kotlin-reflect")
+    testImplementation "org.junit.jupiter:junit-jupiter-api:5.3.2"
+    testRuntimeOnly "org.junit.jupiter:junit-jupiter-engine:5.3.2"
+    testImplementation("org.assertj:assertj-core:3.11.1")
+}
+
+test {
+    // Enable JUnit 5 (Gradle 4.6+).
+    useJUnitPlatform()
+
+    // Always run tests, even when nothing changed.
+    dependsOn 'cleanTest'
+
+    // Show test results.
+    testLogging {
+        events "passed", "skipped", "failed"
+    }
 }

gradle/wrapper/gradle-wrapper.properties

@@ -1,5 +1,6 @@
+#Fri Jan 04 10:36:24 CET 2019
 distributionBase=GRADLE_USER_HOME
 distributionPath=wrapper/dists
-distributionUrl=https\://services.gradle.org/distributions/gradle-5.1-bin.zip
 zipStoreBase=GRADLE_USER_HOME
 zipStorePath=wrapper/dists
+distributionUrl=https\://services.gradle.org/distributions/gradle-4.10.3-all.zip

settings.gradle

@@ -1,2 +1 @@
 rootProject.name = 'design-patterns-kotlin'
-

src/main/kotlin/AbstractFactory.kt

@@ -0,0 +1,45 @@
+import org.assertj.core.api.Assertions.assertThat
+import org.junit.jupiter.api.Test
+
+//Based on: http://stackoverflow.com/a/13030163/361832
+
+interface Plant
+
+class OrangePlant : Plant
+
+class ApplePlant : Plant
+
+abstract class PlantFactory {
+
+    abstract fun makePlant(): Plant
+
+    companion object {
+        inline fun <reified T : Plant> createFactory(): PlantFactory =
+            when (T::class) {
+                OrangePlant::class -> OrangeFactory()
+                ApplePlant::class -> AppleFactory()
+                else -> throw IllegalArgumentException()
+            }
+    }
+}
+
+class AppleFactory : PlantFactory() {
+    override fun makePlant(): Plant = ApplePlant()
+}
+
+class OrangeFactory : PlantFactory() {
+    override fun makePlant(): Plant = OrangePlant()
+}
+
+
+class AbstractFactoryTest {
+
+    @Test
+    fun `Abstract Factory`() {
+        val plantFactory = PlantFactory.createFactory<OrangePlant>()
+        val plant = plantFactory.makePlant()
+        println("Created plant: $plant")
+
+        assertThat(plant).isInstanceOf(OrangePlant::class.java)
+    }
+}

src/main/kotlin/Adapter.kt

@@ -0,0 +1,46 @@
+import org.assertj.core.api.Assertions.assertThat
+import org.junit.jupiter.api.Test
+import java.math.BigDecimal
+
+interface Temperature {
+    var temperature: Double
+}
+
+class CelsiusTemperature(override var temperature: Double) : Temperature
+
+class FahrenheitTemperature(var celsiusTemperature: CelsiusTemperature) : Temperature {
+
+    override var temperature: Double
+        get() = convertCelsiusToFahrenheit(celsiusTemperature.temperature)
+        set(temperatureInF) {
+            celsiusTemperature.temperature = convertFahrenheitToCelsius(temperatureInF)
+        }
+
+    private fun convertFahrenheitToCelsius(f: Double): Double =
+        ((BigDecimal.valueOf(f).setScale(2) - BigDecimal(32)) * BigDecimal(5) / BigDecimal(9))
+            .toDouble()
+
+
+    private fun convertCelsiusToFahrenheit(c: Double): Double =
+        ((BigDecimal.valueOf(c).setScale(2) * BigDecimal(9) / BigDecimal(5)) + BigDecimal(32))
+            .toDouble()
+}
+
+class AdapterTest {
+
+    @Test
+    fun `Adapter`() {
+        val celsiusTemperature = CelsiusTemperature(0.0)
+        val fahrenheitTemperature = FahrenheitTemperature(celsiusTemperature)
+
+        celsiusTemperature.temperature = 36.6
+        println("${celsiusTemperature.temperature} C -> ${fahrenheitTemperature.temperature} F")
+
+        assertThat(fahrenheitTemperature.temperature).isEqualTo(97.88)
+
+        fahrenheitTemperature.temperature = 100.0
+        println("${fahrenheitTemperature.temperature} F -> ${celsiusTemperature.temperature} C")
+
+        assertThat(celsiusTemperature.temperature).isEqualTo(37.78)
+    }
+}

src/test/kotlin/AbstractFactory.kt

@@ -3,7 +3,7 @@ import java.io.File
 // Let's assume that Dialog class is provided by external library.
 // We have only access to Dialog public interface which cannot be changed.
 
-class Dialog() {
+class Dialog {
 
     fun showTitle() = println("showing title")