Refactor target charging apis (#5649)

api/rates.go

@@ -15,20 +15,3 @@ func (r Rates) Current(now time.Time) (Rate, error) {
 
 	return Rate{}, errors.New("no matching rate")
 }
-
-// implement sort.Interface
-func (r Rates) Len() int {
-	return len(r)
-}
-
-func (r Rates) Less(i, j int) bool {
-	if r[i].Price == r[j].Price {
-		return r[i].Start.After(r[j].Start)
-	}
-
-	return r[i].Price < r[j].Price
-}
-
-func (r Rates) Swap(i, j int) {
-	r[i], r[j] = r[j], r[i]
-}

api/rates_test.go

@@ -1,29 +0,0 @@
-package api
-
-import (
-	"sort"
-	"testing"
-	"time"
-
-	"github.com/benbjohnson/clock"
-	"github.com/stretchr/testify/assert"
-)
-
-func TestRatesSortLateSlotsFirst(t *testing.T) {
-	clock := clock.NewMock()
-
-	r := Rates{
-		{
-			Price: 1,
-			Start: clock.Now(),
-		},
-		{
-			Price: 1,
-			Start: clock.Now().Add(time.Hour),
-		},
-	}
-
-	sort.Sort(r)
-	assert.Equal(t, clock.Now().Add(time.Hour), r[0].Start)
-	assert.Equal(t, clock.Now(), r[1].Start)
-}