Cleans up test by removing unused function (#3969)

rules/manager_test.go

@@ -15,7 +15,6 @@ package rules
 
 import (
 	"context"
-	"fmt"
 	"math"
 	"sort"
 	"testing"
@@ -163,14 +162,6 @@ func TestAlertingRule(t *testing.T) {
 	}
 }
 
-func annotateWithTime(lines []string, ts time.Time) []string {
-	annotatedLines := []string{}
-	for _, line := range lines {
-		annotatedLines = append(annotatedLines, fmt.Sprintf(line, timestamp.FromTime(ts)))
-	}
-	return annotatedLines
-}
-
 func TestStaleness(t *testing.T) {
 	storage := testutil.NewStorage(t)
 	defer storage.Close()