'Expecting actual not to be empty' when asserting array after filteredOn

[mitasov-ra]

Describe the bug

1. AssertJ 2.33.0
2. Create a small reproducible example and paste it the the bug report.

   assertThatJson("""[{"id": 123, "name": "abc"}, {"id": 432}]""")
     .isArray()
     .filteredOn("id", 123)
     .first()
     .node("name")
     .isEqualTo(value("abc"))

3. Describe expected behavior
   Everything should be fine but I got:

   [Different value found in node ""] 
   Expecting actual not to be empty
   

[mitasov-ra]

Seems like I've found the cause.

This works:

assertThatJson("""[{"id": 123, "name": "abc"}, {"id": 432}]""")
  .isArray()
  .filteredOn("id", BigDecimal(123))
  .first()
  .node("name")
  .isEqualTo(value("abc"))

[mitasov-ra]

I think such BigDecimal thing still counts as a bug.

Also it's obvious that assertion error message is a bit unclear

[lukas-krecan]

Hi, thanks for feedback.

1. JsonUnit uses BigDecimals for numbers. filteredOn is AssertJ method and since int != BigDecimal the filter does not match
2. The question is, why first did not fail on empty array, will look at it.

[mitasov-ra]

1. I think it is possible to tweak assertions with BigDecimal by making custom type for ACTUAL and overriding equals so it will accept integers.
2. Yep, official AssertJ documentation says that first should fail on empty iterable

[lukas-krecan]

Just checked it. Expecting actual not to be empty is the exception form the first method. I will considering removing the message [Different value found in node ""] which is technically correct, but may be confusing in this case.

[mitasov-ra]

Just noticed that when using filteredOn on an POJO list then message containing something like [Filtered on ...] is added to error report. I think this is what missing.