Why is assertEquals(double,double) deprecated in JUnit?
Solution 1:
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.
Solution 2:
People explain but don't give samples... So here goes what worked for me:
@Test
public void WhenMakingDepositAccountBalanceIncreases() {
Account account = new Account();
account.makeDeposit(10.0);
assertEquals("Account balance was not correct.", 10.0, account.getBalance(), 0);
}
The 0
in the end;
Solution 3:
assertEquals(double, double)
is deprecated because the 2 doubles may be the same but if they are calculated values, the processor may make them slightly different values.
If you try this, it will fail: assertEquals(.1 + .7, .8)
. This was tested using an Intel® processor.
Calling the deprecated method will trigger fail("Use assertEquals(expected, actual, delta) to compare floating-point numbers");
to be called.
Solution 4:
Old question but this hasn't been said yet and might help someone.
You can use com.google.common.math.DoubleMath.fuzzyEquals(double a, double b, double tolerance)
which allows you to specify how close the two doubles should be to each other.
I found it very handy for unit tests where I don't want to hardcode test result values with a lot of decimal places.