Add a cause to the munit Checker failure

[brendanmaguire]

• Add an ErrorItems exception as the failure cause
• This allows clients to inspect and filter failures on their underlying cause Items

[jatcwang]

Just for my own learning, @brendanmaguire can you briefly explain what "client" you're using that this is helpful? :)

[brendanmaguire]

@jatcwang Sorry, client was probably the wrong word above 🙂 I am using this with the Big Query JDBC driver like so:

class QueriesItUtils extends munit.FunSuite with IOCheckerWithErrors {
  override val transactor: Transactor[IO] = TransactorUtils.transactor[IO]()

  test("my query should be valid")(checkQuery(sql.myQuery))

  private def checkQuery[A](query: Query0[A]) = ignoreNullableFieldErrors(check(query))

  // The BigQuery JDBC driver does not convey metadata about the nullability of the columns. By ignoring nullable errors
  // the type check tests can still be run and provide useful information about misaligned queries and schema
  private def ignoreNullableFieldErrors(checkResult: => Unit) =
    Try(checkResult).recover {
      case failException: munit.FailException =>
        failException.cause match {
          case ErrorItems(items) if onlyNullableFieldErrors(items) => ()
          case _                                                   => throw failException
        }
    }.get

  private def onlyNullableFieldErrors(items: List[AnalysisReport.Item]): Boolean =
    items
      .flatMap(_.error)
      .forall(_.lines.forall(_.startsWith(nullableFieldErrorString)))

  private val nullableFieldErrorString = "Reading a NULL value into"
}

[jatcwang]

I see that makes sense :)