[SOLVED] How to check for equality or both blank in AssertJ?

How to check for equality or both blank in AssertJ?

I want to assert that expected and actual are equal to each other. It is ok if both are null or blank ("") -- i.e. null means blank.

.withComparator(...).isEqualTo(expected) does not work, because null is checked before by AspectJ:

@Given("^data is \"([^\"]*)\"$")
void theDataIs(String arg) {
    assertThat(msg.getData())
      .usingComparator(blankOkComperator).isEqualTo(arg);
}

My comparator is Kotlin, but you get the idea:

object blankOkComperator : Comparator<String> {
    override fun compare(o1: String?, o2: String?): Int {
        if(StringUtils.isBlank(o1) && StringUtils.isBlank(o2)) return 0
        if(StringUtils.isBlank(o1)) return -1
        if(StringUtils.isBlank(o2)) return 1
        return o1!!.compareTo(o2!!)
    }
}

I only managed to implement the check by overriding AssertJ's Condition<String> but it looks not very assert-j-ish to me:

@Given("^data is \"([^\"]*)\"$")
void theDataIs(String arg) {
    assertThat(msg.getDate())
      .is(new EqualToOrBothBlank(arg));
}

Again, the helper is Kotlin, but you know what I mean:

class EqualToOrBothBlank(val expected: String) : Condition<String?>() {
    override fun matches(actual: String?): Boolean {
        if(StringUtils.isBlank(actual) && StringUtils.isBlank(expected)) return true;
        return StringUtils.equals(actual, expected)
    }
}

Is there an AspectJ-way to implement the check?

Solution

At the moment you have to use a Condition but it is a fair point for AssertJ not to check for null if one is using a specific comparator, I have created https://github.com/joel-costigliola/assertj-core/issues/1121 for that.

In the meantime, I would put the condition instance into a field to make the code more readable:

@Given("^data is \"([^\"]*)\"$")
void theDataIs(String arg) {
    assertThat(msg.getDate()).is(equalToOrBothBlank(arg));
}

Oh and you are mentioning AspectJ instead of AssertJ a few times :D