chore: Move private packages to internal (#1664)

internal/testutils/testutils.go

@@ -0,0 +1,42 @@
+//go:build windows
+
+package testutils
+
+import (
+	"io"
+	"log/slog"
+	"testing"
+
+	"github.com/alecthomas/kingpin/v2"
+	"github.com/prometheus-community/windows_exporter/pkg/collector"
+	"github.com/prometheus/client_golang/prometheus"
+	"github.com/stretchr/testify/require"
+)
+
+func FuncBenchmarkCollector[C collector.Collector](b *testing.B, name string, collectFunc collector.BuilderWithFlags[C]) {
+	b.Helper()
+
+	logger := slog.New(slog.NewTextHandler(io.Discard, nil))
+
+	c := collectFunc(kingpin.CommandLine)
+	collectors := collector.New(map[string]collector.Collector{name: c})
+	require.NoError(b, collectors.Build(logger))
+
+	// Create perflib scrape context.
+	// Some perflib collectors required a correct context,
+	// or will fail during benchmark.
+	scrapeContext, err := collectors.PrepareScrapeContext()
+	require.NoError(b, err)
+
+	metrics := make(chan prometheus.Metric)
+
+	go func() {
+		for {
+			<-metrics
+		}
+	}()
+
+	for i := 0; i < b.N; i++ {
+		require.NoError(b, c.Collect(scrapeContext, logger, metrics))
+	}
+}