Why is assertEquals(double,double) deprecated in JUnit?

java junit junit4
jsh6303 picture jsh6303 · Oct 22, 2015 · Viewed 78.7k times · Source

I was wondering why assertEquals(double, double) is deprecated.

I used import static org.junit.Assert.assertEquals; and I used JUnit 4.11.

Below is my code:

import org.junit.Test;
import static org.junit.Assert.assertEquals;


public class AccountTest {

@Test
public void test() {
    Account checking = new Account(Account.CHECKING);
    checking.deposit(1000.0);
    checking.withdraw(100.0);
    assertEquals(900.0, checking.getBalance());
   }
}

checking.getBalance() returns a double value.

What could be wrong?

Answer

Codebender picture Codebender · Oct 22, 2015

It's deprecated because of the double's precision problems.

If you note, there's another method assertEquals(double expected, double actual, double delta) which allows a delta precision loss.

JavaDoc:

Asserts that two doubles are equal to within a positive delta. If they are not, an AssertionError is thrown. If the expected value is infinity then the delta value is ignored.NaNs are considered equal: assertEquals(Double.NaN, Double.NaN, *) passes

...

delta - the maximum delta between expected and actual for which both numbers are still considered equal.

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