XmlUnit 2.6.[3,4] is not compatible with AssertJ-Core 3.15.0

[jwalter]

The following test:

@Test
  fun `assertThatXml_valueByXPath should work`() {
    val xml = """
      <fruit>
        <color>yellow</color>
      </fruit>
    """
    assertThatXml(xml).valueByXPath("//color").isEqualTo("yellow")
  }

will throw an error when trying to run with assertj 3.15.0 on the classpath:

java.lang.NoSuchMethodError: org.xmlunit.assertj.ValueAssert.describedAs(Ljava/lang/String;[Ljava/lang/Object;)Lorg/assertj/core/api/AbstractAssert;

	at org.xmlunit.assertj.ValueAssert.create(ValueAssert.java:68)
	at org.xmlunit.assertj.XmlAssert.valueByXPath(XmlAssert.java:202)

The cause is that assertj 3.15.0 moved the `describedAs´method from AbstractAssert to Descriptable and due to type erasure the method return type changed on the byte code level from AbstractAssert to Object.

This currently affects all Spring Boot projects using the milestone M2, M3 or M4 builds of Spring Boot 2.3.0.

[bodewig]

I'm not an AssertJ user myself. I wonder whether the AssertJ devs realize they are breaking binary compatibility repeatedly and make people who provide custom assertions unhappy. This is not the first time, see #135 and #166

I'll try to see whether there is a way to adapt without breaking support for older versions - unless @krystiankaluzny beats me to it.

[bodewig]

I've simply overridden the method and duplicated the implementation -which hasn't changed since at least 2.9.0. Calling super would - of course - not work because of the same NoSuchMethod exception.

I've also added an easier setup for compatibility tests in Travis.

[bodewig]

I've just published a 2.7.0-SNAPSHOT version. @jwalter it would be good if yo could confirm this version works for you.

[jwalter]

2.7.0-SNAPSHOT solves the reported issue for me. Thanks!

[snicoll]

@jwalter thanks for testing!

@bodewig for the record we are releasing Spring Boot 2.3 GA this Thursday if that makes sense (and if you have time) to squeeze a release of XMLUnit in the meantime.

[bodewig]

will do tonight (CEST :-) )

Thanks for testing.

[bodewig]

2.7.0 should show up in maven central soonish, I've just released the Nexus repo.