KTLN-479 (#862)

* KTLN-479 compare classes of objects

* KTLN-479 changed test class names

* Changed test function names

Author: thebaubau

kotlin-reflection/src/main/kotlin/com/baeldung/compare/kclass/Weapon.kt

@@ -0,0 +1,11 @@
+package com.baeldung.compare.kclass
+
+open class Weapon
+
+open class Sword : Weapon()
+
+open class Bow : Weapon()
+
+class Claymore : Sword()
+
+class LongBow : Bow()

kotlin-reflection/src/test/kotlin/com/baeldung/compare/kclass/inheritance/InheritanceUnitTest.kt

@@ -0,0 +1,39 @@
+package com.baeldung.compare.kclass.inheritance
+
+import com.baeldung.compare.kclass.*
+import org.assertj.core.api.Assertions.assertThat
+import org.junit.jupiter.api.Assertions.assertEquals
+import org.junit.jupiter.api.Assertions.assertNotEquals
+import org.junit.jupiter.api.Test
+import kotlin.reflect.full.allSuperclasses
+import kotlin.reflect.full.isSubclassOf
+import kotlin.reflect.full.isSuperclassOf
+import kotlin.reflect.full.superclasses
+
+class InheritanceUnitTest {
+    @Test
+    fun `Different weapons indirectly inherit from Weapon class`() {
+        val weapons = listOf(Sword(), Claymore(), Bow(), LongBow())
+
+        assertThat(weapons).allMatch { it::class.allSuperclasses.contains(Weapon::class) }
+        assertThat(weapons).allMatch { it::class.isSubclassOf(Weapon::class) }
+
+        assertEquals(weapons, weapons.filter { it::class.allSuperclasses.contains(Weapon::class) })
+    }
+
+    @Test
+    fun `Different weapons directly inherit from Weapon class`() {
+        val weapons = listOf(Sword(), Claymore(), Bow(), LongBow())
+
+        assertThat(weapons).anyMatch { it::class.superclasses.contains(Weapon::class) }
+
+        assertNotEquals(weapons, weapons.filter { it::class.superclasses.contains(Weapon::class) })
+    }
+
+    @Test
+    fun `Weapon class is a superclass of different weapons`() {
+        val weapons = listOf(Sword(), Claymore(), Bow(), LongBow())
+
+        assertThat(weapons).allMatch { Weapon::class.isSuperclassOf(it::class) }
+    }
+}

kotlin-reflection/src/test/kotlin/com/baeldung/compare/kclass/isoperator/IsOperatorUnitTest.kt

@@ -0,0 +1,20 @@
+package com.baeldung.compare.kclass.isoperator
+
+import com.baeldung.compare.kclass.Claymore
+import com.baeldung.compare.kclass.Sword
+import com.baeldung.compare.kclass.Weapon
+import org.assertj.core.api.Assertions.assertThat
+import org.junit.jupiter.api.Test
+
+class IsOperatorUnitTest {
+    @Test
+    fun `Different swords are Weapons`() {
+        val weapon = Weapon()
+        val sword = Sword()
+        val claymore = Claymore()
+
+        assertThat(weapon is Weapon).isTrue()
+        assertThat(sword is Weapon).isTrue()
+        assertThat(claymore is Weapon).isTrue()
+    }
+}

kotlin-reflection/src/test/kotlin/com/baeldung/compare/kclass/literal/LiteralUnitTest.kt

@@ -0,0 +1,21 @@
+package com.baeldung.compare.kclass.literal
+
+import com.baeldung.compare.kclass.Weapon
+import org.assertj.core.api.Assertions.assertThat
+import org.junit.jupiter.api.Assertions.assertEquals
+import org.junit.jupiter.api.Assertions.assertInstanceOf
+import org.junit.jupiter.api.Test
+
+class LiteralUnitTest {
+    @Test
+    fun `A sword and a bow are Weapons`() {
+        val sword = Weapon()
+        val bow = Weapon()
+
+        assertEquals(sword::class, bow::class)
+        assertThat(sword::class).isEqualTo(bow::class)
+
+        assertThat(sword).isInstanceOf(Weapon::class.java)
+        assertInstanceOf(Weapon::class.java, sword)
+    }
+}

kotlin-reflection/src/test/kotlin/com/baeldung/compare/kclass/properties/PropertiesUnitTest.kt

@@ -0,0 +1,36 @@
+package com.baeldung.compare.kclass.properties
+
+import com.baeldung.compare.kclass.Weapon
+import org.junit.jupiter.api.Assertions.assertEquals
+import org.junit.jupiter.api.Assertions.assertNotEquals
+import org.junit.jupiter.api.Test
+
+class PropertiesUnitTest {
+    @Test
+    fun `A Kotlin Weapon class is not a Java Weapon class`() {
+        assertEquals("class com.baeldung.compare.kclass.Weapon", Weapon::class.toString())
+        assertEquals("class com.baeldung.compare.kclass.Weapon", Weapon::class.java.toString())
+
+        assertNotEquals(Weapon::class, Weapon::class.java)
+    }
+
+    @Test
+    fun `Using javaClass and kotlin properties for equality comparison`() {
+        val sword = Weapon()
+        val bow = Weapon()
+
+        assertEquals("class com.baeldung.compare.kclass.Weapon", sword.javaClass.toString())
+        assertEquals("class com.baeldung.compare.kclass.Weapon", bow.javaClass.kotlin.toString())
+
+        assertEquals(sword.javaClass, bow.javaClass)
+        assertEquals(sword.javaClass.kotlin, bow.javaClass.kotlin)
+    }
+
+    @Test
+    fun `Comparing javaClass and kotlin properties for Weapon class`(){
+        val sword = Weapon()
+        val bow = Weapon()
+
+        assertNotEquals(sword.javaClass, bow.javaClass.kotlin)
+    }
+}