better otel i think

internal/collector/collector_test.go

@@ -509,3 +509,50 @@ func TestHandleLogsIngestRateLimited(t *testing.T) {
 		t.Fatalf("expected ingest rate limiting to eventually return 429, last code was %d", lastCode)
 	}
 }
+
+func TestHandleVitalsStoresOnePageVitalsRecord(t *testing.T) {
+	c := New(noopBroadcaster{}, 100, &mockStore{})
+	body := `{"service":"shop","session":"s1","pageView":"pv1","url":"https://x/y","nav":"navigate",
+		"metrics":{"LCP":{"value":3100.4,"attribution":{"target":"img.hero","nested":{"x":1}}},
+		"CLS":{"value":0.05},"BOGUS":{"value":1},"INP":{"value":-3}}}`
+	req := httptest.NewRequest(http.MethodPost, "/v1/vitals", strings.NewReader(body))
+	req.Header.Set("Content-Type", "text/plain;charset=UTF-8")
+	rr := httptest.NewRecorder()
+	c.HandleVitals(rr, req)
+	if rr.Code != http.StatusNoContent {
+		t.Fatalf("status = %d, body %s", rr.Code, rr.Body.String())
+	}
+
+	vb := vitalsBeacon{}
+	if err := json.Unmarshal([]byte(body), &vb); err != nil {
+		t.Fatal(err)
+	}
+	logs, ok := vb.toLogs(time.Unix(1, 0))
+	if !ok {
+		t.Fatal("expected valid logs")
+	}
+	rec := logs.ResourceLogs().At(0).ScopeLogs().At(0).LogRecords().At(0)
+	attrs := rec.Attributes()
+	if v, _ := attrs.Get("vitals.lcp.rating"); v.Str() != "needs-improvement" {
+		t.Errorf("lcp rating = %q", v.Str())
+	}
+	if v, _ := attrs.Get("vitals.cls"); v.Double() != 0.05 {
+		t.Errorf("cls = %v (must not be rounded)", v.Double())
+	}
+	if _, found := attrs.Get("vitals.inp"); found {
+		t.Error("negative INP must be dropped")
+	}
+	if strings.Contains(rec.Body().Str(), "BOGUS") || strings.Contains(rec.Body().Str(), "nested") {
+		t.Errorf("unknown metric or non-scalar attribution leaked: %s", rec.Body().Str())
+	}
+}
+
+func TestHandleVitalsRejectsEmpty(t *testing.T) {
+	c := New(noopBroadcaster{}, 100, &mockStore{})
+	req := httptest.NewRequest(http.MethodPost, "/v1/vitals", strings.NewReader(`{"metrics":{}}`))
+	rr := httptest.NewRecorder()
+	c.HandleVitals(rr, req)
+	if rr.Code != http.StatusBadRequest {
+		t.Fatalf("status = %d", rr.Code)
+	}
+}