init monlet repo with stage 0-2 (docs, contract, agent MVP)

agent/internal/metrics/metrics_test.go

@@ -0,0 +1,34 @@
+package metrics
+
+import (
+	"io"
+	"net/http"
+	"net/http/httptest"
+	"strings"
+	"testing"
+
+	"github.com/prometheus/client_golang/prometheus/promhttp"
+)
+
+func TestMetricsExposeRegistered(t *testing.T) {
+	m := New()
+	m.CheckRuns.WithLabelValues("c1", "ok").Inc()
+	m.SpoolDepth.Set(7)
+	srv := httptest.NewServer(promhttp.HandlerFor(m.Registry, promhttp.HandlerOpts{}))
+	defer srv.Close()
+	resp, err := http.Get(srv.URL)
+	if err != nil {
+		t.Fatal(err)
+	}
+	defer resp.Body.Close()
+	body, _ := io.ReadAll(resp.Body)
+	s := string(body)
+	for _, want := range []string{
+		`monlet_agent_check_runs_total{check_id="c1",status="ok"} 1`,
+		`monlet_agent_spool_events 7`,
+	} {
+		if !strings.Contains(s, want) {
+			t.Errorf("missing %q in output", want)
+		}
+	}
+}