[Step1] kotlin basics

src/main/kotlin/step1/Person.kt

@@ -0,0 +1,7 @@
+package step1
+
+data class Person(
+    val name: String,
+    val age: Int? = null,
+    var nickname: String? = null,
+)

src/test/kotlin/step1/PersonTest.kt

@@ -0,0 +1,51 @@
+package step1
+
+import org.assertj.core.api.Assertions.assertThat
+import org.junit.jupiter.api.Test
+import org.junit.jupiter.api.assertAll
+
+class PersonTest {
+    val name = "김철수"
+    val age = 20
+    val nickname = "아이언워터"
+    @Test
+    internal fun `named arguments`() {
+        val people = listOf(
+            Person(name, age, nickname),
+            Person(name, age, nickname = nickname),
+            Person(name = name, nickname = nickname, age = age),
+        )
+        assertThat(people).allSatisfy {
+            assertThat(it.name).isEqualTo(name)
+            assertThat(it.age).isEqualTo(age)
+            assertThat(it.nickname).isEqualTo(nickname)
+        }
+    }
+
+    @Test
+    internal fun `nullable types`() {
+        val person = Person(name, null, null)
+        assertAll(
+            { assertThat(person.name).isEqualTo(name) },
+            { assertThat(person.age).isNull() },
+            { assertThat(person.nickname).isNull() },
+        )
+    }
+
+    @Test
+    internal fun `default arguments`() {
+        val person = Person(name)
+        assertAll(
+            { assertThat(person.name).isEqualTo(name) },
+            { assertThat(person.age).isNull() },
+            { assertThat(person.nickname).isNull() },
+        )
+    }
+
+    @Test
+    internal fun `data classes`() {
+        val person1 = Person(name, age, nickname)
+        val person2 = Person(name, age, nickname)
+        assertThat(person1).isEqualTo(person2)
+    }
+}