initial working version

internal/dnstt/exporter_test.go

@@ -0,0 +1,42 @@
+package dnstt
+
+import (
+	"strings"
+	"testing"
+	"time"
+
+	"github.com/prometheus/client_golang/prometheus/testutil"
+)
+
+func TestExporterCollectsAggregateDNSTTMetrics(t *testing.T) {
+	now := time.Unix(1000, 0)
+	c := NewCollector([]string{"tunnel.example.com"}, WithNow(func() time.Time { return now }))
+	c.RecordQuery("tunnel.example.com", "client-a", 100)
+	c.RecordQuery("tunnel.example.com", "client-b", 300)
+	c.RecordResponse("tunnel.example.com", 250)
+
+	expected := `
+# HELP dnstt_active_clients Number of DNSTT client sessions observed within the active timeout window.
+# TYPE dnstt_active_clients gauge
+dnstt_active_clients{domain="tunnel.example.com"} 2
+# HELP dnstt_bytes_in_total Total bytes observed in DNSTT DNS queries.
+# TYPE dnstt_bytes_in_total counter
+dnstt_bytes_in_total{domain="tunnel.example.com"} 400
+# HELP dnstt_bytes_out_total Total bytes observed in DNSTT DNS responses.
+# TYPE dnstt_bytes_out_total counter
+dnstt_bytes_out_total{domain="tunnel.example.com"} 250
+# HELP dnstt_peak_clients Maximum concurrent active DNSTT client sessions observed.
+# TYPE dnstt_peak_clients gauge
+dnstt_peak_clients{domain="tunnel.example.com"} 2
+# HELP dnstt_queries_total Total DNSTT DNS queries observed.
+# TYPE dnstt_queries_total counter
+dnstt_queries_total{domain="tunnel.example.com"} 2
+# HELP dnstt_sessions_total Total unique DNSTT client sessions observed.
+# TYPE dnstt_sessions_total counter
+dnstt_sessions_total{domain="tunnel.example.com"} 2
+`
+
+	if err := testutil.CollectAndCompare(NewExporter(c), strings.NewReader(expected)); err != nil {
+		t.Fatal(err)
+	}
+}