Merge pull request #1037 from sk1418/iterate-enum-items

Iterate enum items

Author: theangrydev

core-kotlin-modules/core-kotlin-lang-oop-4/src/test/kotlin/iterateEnumEntries/IterateEnumEntriesUnitTest.kt

@@ -0,0 +1,60 @@
+package iterateEnumEntries
+
+import iterateEnumEntries.Holiday.*
+import iterateEnumEntries.Weekday.*
+import org.junit.jupiter.api.Assertions.*
+import org.junit.jupiter.api.Test
+
+enum class Weekday {
+    MON, TUE, WED, THU, FRI
+}
+
+enum class Holiday {
+    Eastern, Christmas, LaborDay, NewYear
+}
+
+class IterateEnumEntriesUnitTest {
+    private val expectedWeekdayArray = arrayOf(MON, TUE, WED, THU, FRI)
+    private val expectedWeekdayList = listOf(MON, TUE, WED, THU, FRI)
+
+    private val expectedHolidayArray = arrayOf(Eastern, Christmas, LaborDay, NewYear)
+
+    @Test
+    fun `when using values() then get correct iterable`() {
+        val result = Weekday.values()
+        assertArrayEquals(expectedWeekdayArray, result)
+    }
+
+    @Test
+    fun `when using entries() then get correct iterable`() {
+        val result = Weekday.entries
+        assertEquals(expectedWeekdayList, result)
+    }
+
+    @Test
+    fun `when using enumValues() then get correct iterable`() {
+        val weekdayResult = enumValues<Weekday>()
+        assertArrayEquals(expectedWeekdayArray, weekdayResult)
+
+        val holidayResult = enumValues<Holiday>()
+        assertArrayEquals(expectedHolidayArray, holidayResult)
+    }
+
+    inline fun <reified E : Enum<E>> findEnumByName(name: String): E? {
+        // E.values() or E.entries doesn't compile
+        return enumValues<E>().firstOrNull { it.name.equals(name.replace(" ", ""), ignoreCase = true) }
+    }
+
+
+    @Test
+    fun `when using the generic itemNames then get correct iterable`() {
+        val tuesday = findEnumByName<Weekday>("t U e")
+        assertEquals(TUE, tuesday)
+
+        val newYear = findEnumByName<Holiday>("N E W Y E A R")
+        assertEquals(NewYear, newYear)
+
+        val unknown = findEnumByName<Holiday>("Thanksgiving")
+        assertNull(unknown)
+    }
+}