Compare Date objects with different levels of precision

Question

I have a JUnit test that fails because the milliseconds are different. In this case I don\'t care about the milliseconds. How can I change the precision of the assert to i

Answer 1

I did a small class that might be useful for some googlers that end up here : https://stackoverflow.com/a/37168645/5930242

Answer 2

In JUnit you can program two assert methods, like this:

public class MyTest {
  @Test
  public void test() {
    ...
    assertEqualDates(expectedDateObject, resultDate);

    // somewhat more confortable:
    assertEqualDates("01/01/2012", anotherResultDate);
  }

  private static final String DATE_PATTERN = "dd/MM/yyyy";

  private static void assertEqualDates(String expected, Date value) {
      DateFormat formatter = new SimpleDateFormat(DATE_PATTERN);
      String strValue = formatter.format(value);
      assertEquals(expected, strValue);
  }

  private static void assertEqualDates(Date expected, Date value) {
    DateFormat formatter = new SimpleDateFormat(DATE_PATTERN);
    String strExpected = formatter.format(expected);
    String strValue = formatter.format(value);
    assertEquals(strExpected, strValue);
  }
}

Answer 3

Convert the dates to String using SimpleDateFromat, specify in the constructor the required date/time fields and compare the string values:

SimpleDateFormat formatter = new SimpleDateFormat("yyyy-MM-dd HH:mm:ss");
String expectedDate = formatter.format(dateOne));
String dateToTest = formatter.format(dateTwo);
assertEquals(expectedDate, dateToTest);

Answer 4

I don't know if there is support in JUnit, but one way to do it:

import java.text.SimpleDateFormat;
import java.util.Date;

public class Example {

    private static SimpleDateFormat formatter = new SimpleDateFormat("dd MMM yyyy HH:mm:ss");

    private static boolean assertEqualDates(Date date1, Date date2) {
        String d1 = formatter.format(date1);            
        String d2 = formatter.format(date2);            
        return d1.equals(d2);
    }    

    public static void main(String[] args) {
        Date date1 = new Date();
        Date date2 = new Date();

        if (assertEqualDates(date1,date2)) { System.out.println("true!"); }
    }
}

Answer 5

Here is a utility function that did the job for me.

    private boolean isEqual(Date d1, Date d2){
        return d1.toLocalDate().equals(d2.toLocalDate());
    }

Answer 6

use AssertJ assertions for Joda-Time (http://joel-costigliola.github.io/assertj/assertj-joda-time.html)

import static org.assertj.jodatime.api.Assertions.assertThat;
import org.joda.time.DateTime;

assertThat(new DateTime(dateOne.getTime())).isEqualToIgnoringMillis(new DateTime(dateTwo.getTime()));

the test failing message is more readable

java.lang.AssertionError: 
Expecting:
  <2014-07-28T08:00:00.000+08:00>
to have same year, month, day, hour, minute and second as:
  <2014-07-28T08:10:00.000+08:00>
but had not.