Granularity

// this is here to remove noisy warnings
import org.scalacheck.Prop.forAll

If you wish to restrict the precision of the generated instances, this library refers to that as granularity.

You can constrain the granularity to:

• Seconds
• Minutes
• Hours
• Days
• Years

When a value is constrained, the time fields are set to zero, and the rest to the first day of the month, or day of the year. For example, if you constrain a field to be years, the generated instance will be midnight exactly, on the first day of January.

To constrain a generated type, you simply need to provide an import for the typeclass for your date/time and range, and also an import for the granularity. As an example, this time using Java SE 8’s java.time package:

import java.time._
import com.fortysevendeg.scalacheck.datetime.jdk8.ArbitraryJdk8._
import com.fortysevendeg.scalacheck.datetime.jdk8.granularity.years

val prop = forAll { (zdt: ZonedDateTime) =>
  (zdt.getMonth == Month.JANUARY) &&
  (zdt.getDayOfMonth == 1) &&
  (zdt.getHour == 0) &&
  (zdt.getMinute == 0) &&
  (zdt.getSecond == 0) &&
  (zdt.getNano == 0)
}

prop.check()