Merge pull request #14342 from azhwani/BAEL-6399

BAEL-6399: Getting Yesterday's Date in Java

core-java-modules/core-java-date-operations-3/src/test/java/com/baeldung/date/GetYesterdayDateUnitTest.java

@@ -0,0 +1,71 @@
+package com.baeldung.date;
+
+import static org.junit.jupiter.api.Assertions.assertEquals;
+
+import java.time.LocalDate;
+import java.util.Calendar;
+import java.util.Date;
+import java.util.GregorianCalendar;
+
+import org.apache.commons.lang3.time.DateUtils;
+import org.joda.time.Instant;
+import org.junit.jupiter.api.Test;
+
+class GetYesterdayDateUnitTest {
+
+    @SuppressWarnings("deprecation")
+    @Test
+    void givenDate_whenUsingDateClass_thenReturnYesterday() {
+        Date currentDate = new Date(2023, Calendar.DECEMBER, 20);
+        Date yesterdayDate = new Date(currentDate.getTime() - 24 * 60 * 60 * 1000);
+        Date expectedYesterdayDate = new Date(2023, Calendar.DECEMBER, 19);
+
+        assertEquals(expectedYesterdayDate, yesterdayDate);
+    }
+
+    @Test
+    void givenDate_whenUsingCalendarClass_thenReturnYesterday() {
+        Calendar date = new GregorianCalendar(2023, Calendar.APRIL, 20, 4, 0);
+        date.add(Calendar.DATE, -1);
+        Calendar expectedYesterdayDate = new GregorianCalendar(2023, Calendar.APRIL, 19, 4, 0);
+
+        assertEquals(expectedYesterdayDate, date);
+    }
+
+    @Test
+    void givenDate_whenUsingLocalDateClass_thenReturnYesterday() {
+        LocalDate localDate = LocalDate.of(2023, 12, 20);
+        LocalDate yesterdayDate = localDate.minusDays(1);
+        LocalDate expectedYesterdayDate = LocalDate.of(2023, 12, 19);
+
+        assertEquals(expectedYesterdayDate, yesterdayDate);
+    }
+
+    @Test
+    void givenDate_whenUsingInstantClass_thenReturnYesterday() {
+        Instant date = Instant.parse("2023-10-25");
+        Instant yesterdayDate = date.minus(24 * 60 * 60 * 1000);
+        Instant expectedYesterdayDate = Instant.parse("2023-10-24");
+
+        assertEquals(expectedYesterdayDate, yesterdayDate);
+    }
+
+    @Test
+    void givenDate_whenUsingJodaTimeLocalDateClass_thenReturnYesterday() {
+        org.joda.time.LocalDate localDate = new org.joda.time.LocalDate(2023, 12, 20);
+        org.joda.time.LocalDate yesterdayDate = localDate.minusDays(1);
+        org.joda.time.LocalDate expectedYesterdayDate = new org.joda.time.LocalDate(2023, 12, 19);
+
+        assertEquals(expectedYesterdayDate, yesterdayDate);
+    }
+
+    @Test
+    void givenDate_whenUsingApacheCommonsLangDateUtils_thenReturnYesterday() {
+        Date date = new GregorianCalendar(2023, Calendar.MAY, 16, 4, 0).getTime();
+        Date yesterdayDate = DateUtils.addDays(date, -1);
+        Date expectedYesterdayDate = new GregorianCalendar(2023, Calendar.MAY, 15, 4, 0).getTime();
+
+        assertEquals(expectedYesterdayDate, yesterdayDate);
+    }
+
+}