Working with unit tests

We will work on an example function that sorts time.Time values in ascending or descending order, which is given here:

package sort
import (
  "sort"
  "time"
)
// Sort times in ascending or descending order
func SortTimes(input []time.Time, asc bool) []time.Time {
  output := make([]time.Time, len(input))
  copy(output, input)
  if asc {
    sort.Slice(output, func(i, j int) bool {
      return output[i].Before(output[j])
    })
    return output
  }
  sort.Slice(output, func(i, j int) bool {
    return output[j].Before(output[i])
  })
  return output
}

We will use the built-in testing tools provided by the Go build system and the standard library. For this, let’s suppose we stored the preceding function in a file called sort.go...