zio-test Gen.offsetDateTime.genOffset might fail with invalid bounds

[DaniRey]

The offset of the minLocalDate might be bigger then the offset of the maxLocalDate.

I suggest the following solution

  /**
   * A generator of `java.time.OffsetDateTime` values inside the specified
   * range: [min, max]. Shrinks toward min.
   */
  final def offsetDateTime(min: OffsetDateTime, max: OffsetDateTime)(implicit
                                                                     trace: Trace
  ): Gen[Any, OffsetDateTime] = {

    def genLocalDateTime(min: OffsetDateTime, max: OffsetDateTime): Gen[Any, LocalDateTime] = {
      val minInst = min.toInstant
      val maxInst = max.toInstant
      instant(minInst, maxInst).map(_.atOffset(utc).toLocalDateTime)
    }

    def genOffset(min: OffsetDateTime, max: OffsetDateTime, actual: LocalDateTime): Gen[Any, ZoneOffset] = {
      val minLocalDate = min.atZoneSimilarLocal(utc).toLocalDate
      val maxLocalDate = max.atZoneSimilarLocal(utc).toLocalDate
      val actualLocalDate = actual.toLocalDate
      val zoneOffsetMin = -18 * 3600
      val zoneOffsetMax = 18 * 3600
      val minOffsetSeconds = if (minLocalDate == actualLocalDate) min.getOffset.getTotalSeconds else zoneOffsetMin
      val maxOffsetSeconds = if (maxLocalDate == actualLocalDate) max.getOffset.getTotalSeconds else zoneOffsetMax
      if (minOffsetSeconds > maxOffsetSeconds) {
        val secondsAfterMin = (min.toInstant.toEpochMilli - actual.toInstant(utc).toEpochMilli) / 1000
        val secondsBeforeMax = (max.toInstant.toEpochMilli - actual.toInstant(utc).toEpochMilli) / 1000
        Gen.int(Math.max(secondsAfterMin.toInt, zoneOffsetMin), Math.min(secondsBeforeMax.toInt, zoneOffsetMax)).map(ZoneOffset.ofTotalSeconds)
      } else {
        Gen.int(minOffsetSeconds, maxOffsetSeconds).map(ZoneOffset.ofTotalSeconds)
      }
    }

    for {
      localDateTime <- genLocalDateTime(min, max)
      offset <- genOffset(min, max, localDateTime)
    } yield OffsetDateTime.of(localDateTime, offset)
  }

Which is basically the following addition

      if (minOffsetSeconds > maxOffsetSeconds) {
        val secondsAfterMin = (min.toInstant.toEpochMilli - actual.toInstant(utc).toEpochMilli) / 1000
        val secondsBeforeMax = (max.toInstant.toEpochMilli - actual.toInstant(utc).toEpochMilli) / 1000
        Gen.int(Math.max(secondsAfterMin.toInt, zoneOffsetMin), Math.min(secondsBeforeMax.toInt, zoneOffsetMax)).map(ZoneOffset.ofTotalSeconds)
      }

[DaniRey]

For anyone finding this issue before it is resolved.
This might be a good workaround Gen.zonedDateTime(min, max).map(_.toOffsetDateTime)

[adamgfraser]

@DaniRey Thanks for reporting! Pull requests welcome!