Merge pull request #5572 from dkapil/feature/BAEL-896

BAEL-896 Working with dates in Kotlin

kotlin-libraries/src/test/kotlin/com/baeldung/kotlin/dates/CreateDateUnitTest.kt

@@ -0,0 +1,34 @@
+package com.baeldung.kotlin.dates
+
+import org.assertj.core.api.Assertions.assertThat
+import org.junit.jupiter.api.Test
+import java.time.LocalDate
+import java.time.format.DateTimeFormatter
+
+class CreateDateUnitTest {
+
+    @Test
+    fun givenString_whenDefaultFormat_thenCreated() {
+
+        var date = LocalDate.parse("2018-12-31")
+
+        assertThat(date).isEqualTo("2018-12-31")
+    }
+
+    @Test
+    fun givenString_whenCustomFormat_thenCreated() {
+
+        var formatter = DateTimeFormatter.ofPattern("dd-MM-yyyy")
+        var date = LocalDate.parse("31-12-2018", formatter)
+
+        assertThat(date).isEqualTo("2018-12-31")
+    }
+
+    @Test
+    fun givenYMD_whenUsingOf_thenCreated() {
+        var date = LocalDate.of(2018, 12, 31)
+
+        assertThat(date).isEqualTo("2018-12-31")
+    }
+
+}

kotlin-libraries/src/test/kotlin/com/baeldung/kotlin/dates/ExtractDateUnitTest.kt

@@ -0,0 +1,29 @@
+package com.baeldung.kotlin.dates
+
+import org.assertj.core.api.Assertions.assertThat
+import org.junit.jupiter.api.Test
+import java.time.DayOfWeek
+import java.time.LocalDate
+import java.time.Month
+
+class ExtractDateUnitTest {
+
+    @Test
+    fun givenDate_thenExtractedYMD() {
+        var date = LocalDate.parse("2018-12-31")
+
+        assertThat(date.year).isEqualTo(2018)
+        assertThat(date.month).isEqualTo(Month.DECEMBER)
+        assertThat(date.dayOfMonth).isEqualTo(31)
+    }
+
+    @Test
+    fun givenDate_thenExtractedEraDowDoy() {
+        var date = LocalDate.parse("2018-12-31")
+
+        assertThat(date.era.toString()).isEqualTo("CE")
+        assertThat(date.dayOfWeek).isEqualTo(DayOfWeek.MONDAY)
+        assertThat(date.dayOfYear).isEqualTo(365)
+    }
+
+}

kotlin-libraries/src/test/kotlin/com/baeldung/kotlin/dates/FormatDateUnitTest.kt

@@ -0,0 +1,29 @@
+package com.baeldung.kotlin.dates
+
+import org.assertj.core.api.Assertions.assertThat
+import org.junit.jupiter.api.Test
+import java.time.LocalDate
+import java.time.format.DateTimeFormatter
+
+class FormatDateUnitTest {
+
+    @Test
+    fun givenDate_whenDefaultFormat_thenFormattedString() {
+
+        var date = LocalDate.parse("2018-12-31")
+
+        assertThat(date.toString()).isEqualTo("2018-12-31")
+    }
+
+    @Test
+    fun givenDate_whenCustomFormat_thenFormattedString() {
+
+        var date = LocalDate.parse("2018-12-31")
+
+        var formatter = DateTimeFormatter.ofPattern("dd-MMMM-yyyy")
+        var formattedDate = date.format(formatter)
+
+        assertThat(formattedDate).isEqualTo("31-December-2018")
+    }
+
+}

kotlin-libraries/src/test/kotlin/com/baeldung/kotlin/dates/PeriodDateUnitTest.kt

@@ -0,0 +1,48 @@
+package com.baeldung.kotlin.dates
+
+import org.assertj.core.api.Assertions.assertThat
+import org.junit.jupiter.api.Test
+import java.time.LocalDate
+import java.time.Period
+
+class PeriodDateUnitTest {
+
+    @Test
+    fun givenYMD_thenCreatePeriod() {
+        var period = Period.of(1, 2, 3)
+
+        assertThat(period.toString()).isEqualTo("P1Y2M3D")
+    }
+
+    @Test
+    fun givenPeriod_whenAdd_thenModifiedDate() {
+        var period = Period.of(1, 2, 3)
+
+        var date = LocalDate.of(2018, 6, 25)
+        var modifiedDate = date.plus(period)
+
+        assertThat(modifiedDate).isEqualTo("2019-08-28")
+    }
+
+    @Test
+    fun givenPeriod_whenSubtracted_thenModifiedDate() {
+        var period = Period.of(1, 2, 3)
+
+        var date = LocalDate.of(2018, 6, 25)
+        var modifiedDate = date.minus(period)
+
+        assertThat(modifiedDate).isEqualTo("2017-04-22")
+    }
+
+    @Test
+    fun givenTwoDate_whenUsingBetween_thenDiffOfDates() {
+
+        var date1 = LocalDate.parse("2018-06-25")
+        var date2 = LocalDate.parse("2018-12-25")
+
+        var period = Period.between(date1, date2)
+
+        assertThat(period.toString()).isEqualTo("P6M")
+    }
+
+}