Jackson JsonNode comparisons are broken

Which version of Kotest are you using 5.3.1

When comparing two different JsonNodes, shouldBe is erroneously stating they are equal when they have different values at the same key.

Here’s a simple test that reproduces this issue for me:

@Test
fun `it should return detect differences in values`() {
  val map1 = mapOf("test" to 1)
  val map2 = mapOf("test" to 2)
  val mapper = ObjectMapper()
  val jsonNode1 = mapper.valueToTree<JsonNode>(map1)
  val jsonNode2 = mapper.valueToTree<JsonNode>(map2)

  // Passes
  jsonNode1 shouldBe jsonNode2
  // Fails with:
  // expected:<"{"test":2}"> but was:<"{"test":1}">
  jsonNode1.toString() shouldBe jsonNode2.toString()
}

[daviddenton]

My advice would be to remove the is Iterable check and rely on default equality check for these cases, but this decision is probably up to maintainers.

I tend to agree here - keeping Iterable support would seem to be the riskier long-term option, as this issue is likely to keep coming up when it surprises people. 😄

[piotrb5e3]

Hi,

I checked, and dropping is Iterable causes some tests to fail.

There seems to a conceptual issue here. Kotlin iterables are defined as:

Classes that inherit from this interface can be represented as a sequence of elements that can be iterated over.

Java iterables do not have this assumption:

Implementing this interface allows an object to be the target of the enhanced for statement (sometimes called the “for-each loop” statement).

So while it seems idiomatic in kotlin to compare iterables by their content, it probably should not be done, because at least on the JVM platform the implementation class does not make this assumption.

My advice would be to remove the is Iterable check and rely on default equality check for these cases, but this decision is probably up to maintainers.