BAEL-1849 - Convert from String to Date in Java (#4476)

libraries/src/test/java/com/baeldung/date/StringToDateUnitTest.java

@@ -0,0 +1,141 @@
+package com.baeldung.date;
+
+import static org.junit.Assert.assertEquals;
+import static org.assertj.core.api.Assertions.assertThat;
+
+import java.text.ParseException;
+import java.text.SimpleDateFormat;
+import java.time.LocalDate;
+import java.time.LocalDateTime;
+import java.time.ZoneId;
+import java.time.ZonedDateTime;
+import java.time.format.DateTimeFormatter;
+import java.time.format.DateTimeParseException;
+import java.util.Calendar;
+import java.util.Date;
+import java.util.GregorianCalendar;
+import java.util.Locale;
+
+import org.apache.commons.lang3.time.DateUtils;
+import org.joda.time.DateTime;
+import org.junit.Rule;
+import org.junit.Test;
+import org.junit.rules.ExpectedException;
+
+public class StringToDateUnitTest {
+
+    @Rule
+    public ExpectedException thrown = ExpectedException.none();
+
+    @Test
+    public void givenDateString_whenConvertedToDate_thenWeGetCorrectLocalDate() {
+        LocalDate expectedLocalDate = LocalDate.of(2018, 05, 05);
+
+        LocalDate date = LocalDate.parse("2018-05-05");
+
+        assertThat(date).isEqualTo(expectedLocalDate);
+    }
+
+    @Test
+    public void givenDateString_whenConvertedToDate_thenWeGetCorrectLocalDateTime() {
+        LocalDateTime expectedLocalDateTime = LocalDateTime.of(2018, 05, 05, 11, 50, 55);
+
+        LocalDateTime dateTime = LocalDateTime.parse("2018-05-05T11:50:55");
+
+        assertThat(dateTime).isEqualTo(expectedLocalDateTime);
+    }
+
+    @Test
+    public void givenDateString_whenConvertedToDate_thenWeGetDateTimeParseException() {
+        thrown.expect(DateTimeParseException.class);
+        thrown.expectMessage("Text '2018-05-05' could not be parsed at index 10");
+
+        LocalDateTime.parse("2018-05-05");
+    }
+
+    @Test
+    public void givenDateString_whenConvertedToDate_thenWeGetCorrectZonedDateTime() {
+        LocalDateTime localDateTime = LocalDateTime.of(2015, 05, 05, 10, 15, 30);
+        ZonedDateTime expectedZonedDateTime = ZonedDateTime.of(localDateTime, ZoneId.of("Europe/Paris"));
+
+        ZonedDateTime zonedDateTime = ZonedDateTime.parse("2015-05-05T10:15:30+01:00[Europe/Paris]");
+
+        assertThat(zonedDateTime).isEqualTo(expectedZonedDateTime);
+    }
+
+    @Test
+    public void givenDateString_whenConvertedToDateUsingFormatter_thenWeGetCorrectLocalDate() {
+        LocalDate expectedLocalDate = LocalDate.of(1959, 7, 9);
+
+        String dateInString = "19590709";
+        LocalDate date = LocalDate.parse(dateInString, DateTimeFormatter.BASIC_ISO_DATE);
+
+        assertThat(date).isEqualTo(expectedLocalDate);
+    }
+
+    @Test
+    public void givenDateString_whenConvertedToDateUsingCustomFormatter_thenWeGetCorrectLocalDate() {
+        LocalDate expectedLocalDate = LocalDate.of(1980, 05, 05);
+
+        String dateInString = "Mon, 05 May 1980";
+        DateTimeFormatter formatter = DateTimeFormatter.ofPattern("EEE, d MMM yyyy", Locale.ENGLISH);
+        LocalDate dateTime = LocalDate.parse(dateInString, formatter);
+
+        assertThat(dateTime).isEqualTo(expectedLocalDate);
+    }
+
+    @Test
+    public void givenDateString_whenConvertedToDate_thenWeGetCorrectDate() throws ParseException {
+        SimpleDateFormat formatter = new SimpleDateFormat("dd-MMM-yyyy", Locale.ENGLISH);
+
+        String dateInString = "7-Jun-2013";
+        Date date = formatter.parse(dateInString);
+
+        assertDateIsCorrect(date);
+    }
+
+    @Test
+    public void givenDateString_whenConvertedToDate_thenWeGetParseException() throws ParseException {
+        SimpleDateFormat formatter = new SimpleDateFormat("dd-MMM-yyyy", Locale.ENGLISH);
+
+        thrown.expect(ParseException.class);
+        thrown.expectMessage("Unparseable date: \"07/06/2013\"");
+
+        String dateInString = "07/06/2013";
+        formatter.parse(dateInString);
+    }
+
+    @Test
+    public void givenDateString_whenConvertedToDate_thenWeGetCorrectJodaDateTime() {
+        org.joda.time.format.DateTimeFormatter formatter = org.joda.time.format.DateTimeFormat.forPattern("dd/MM/yyyy HH:mm:ss");
+
+        String dateInString = "07/06/2013 10:11:59";
+        DateTime dateTime = DateTime.parse(dateInString, formatter);
+
+        assertEquals("Day of Month should be 7: ", 7, dateTime.getDayOfMonth());
+        assertEquals("Month should be: ", 6, dateTime.getMonthOfYear());
+        assertEquals("Year should be: ", 2013, dateTime.getYear());
+
+        assertEquals("Hour of day should be: ", 10, dateTime.getHourOfDay());
+        assertEquals("Minutes of hour should be: ", 11, dateTime.getMinuteOfHour());
+        assertEquals("Seconds of minute should be: ", 59, dateTime.getSecondOfMinute());
+    }
+
+    @Test
+    public void givenDateString_whenConvertedToDate_thenWeGetCorrectDateTime() throws ParseException {
+        String dateInString = "07/06-2013";
+        Date date = DateUtils.parseDate(dateInString, new String[] { "yyyy-MM-dd HH:mm:ss", "dd/MM-yyyy" });
+
+        assertDateIsCorrect(date);
+    }
+
+    private void assertDateIsCorrect(Date date) {
+        Calendar calendar = new GregorianCalendar(Locale.ENGLISH);
+        calendar.setTime(date);
+
+        assertEquals("Day of Month should be 7: ", 7, calendar.get(Calendar.DAY_OF_MONTH));
+        assertEquals("Month should be: ", 5, calendar.get(Calendar.MONTH));
+        assertEquals("Year should be: ", 2013, calendar.get(Calendar.YEAR));
+    }
+
+}