test(benchmark): add benchmarks for NewWorklog

internal/pkg/worklog/worklog_test.go

@@ -2,11 +2,53 @@ package worklog_test
 
 import (
 	"testing"
+	"time"
 
 	"github.com/gabor-boros/minutes/internal/pkg/worklog"
 	"github.com/stretchr/testify/assert"
 )
 
+var worklogBenchResult worklog.Worklog
+
+func benchmarkNewWorklog(b *testing.B, entryCount int) {
+	b.StopTimer()
+
+	var entries []worklog.Entry
+
+	for i := 0; i != entryCount; i++ {
+		entry := getTestEntry()
+		entry.Start.Add(time.Hour * time.Duration(i))
+		entries = append(entries, entry)
+	}
+
+	b.StartTimer()
+
+	var result worklog.Worklog
+	for n := 0; n != b.N; n++ {
+		result = worklog.NewWorklog(entries)
+	}
+
+	// always store the result to a package level variable
+	// so the compiler cannot eliminate the Benchmark itself.
+	worklogBenchResult = result
+}
+
+func BenchmarkNewWorklog_5(b *testing.B) {
+	benchmarkNewWorklog(b, 5)
+}
+
+func BenchmarkNewWorklog_10(b *testing.B) {
+	benchmarkNewWorklog(b, 10)
+}
+
+func BenchmarkNewWorklog_50(b *testing.B) {
+	benchmarkNewWorklog(b, 50)
+}
+
+func BenchmarkNewWorklog_100(b *testing.B) {
+	benchmarkNewWorklog(b, 100)
+}
+
 func TestWorklogCompleteEntries(t *testing.T) {
 	completeEntry := getTestEntry()