Add tests for prometheus registry.

metrics/prometheus_test.go

@@ -0,0 +1,67 @@
+/**
+ * Standalone signaling server for the Nextcloud Spreed app.
+ * Copyright (C) 2026 struktur AG
+ *
+ * @author Joachim Bauch <bauch@struktur.de>
+ *
+ * @license GNU AGPL version 3 or any later version
+ *
+ * This program is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU Affero General Public License as published by
+ * the Free Software Foundation, either version 3 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU Affero General Public License for more details.
+ *
+ * You should have received a copy of the GNU Affero General Public License
+ * along with this program.  If not, see <http://www.gnu.org/licenses/>.
+ */
+package metrics
+
+import (
+	"testing"
+
+	"github.com/prometheus/client_golang/prometheus"
+	"github.com/stretchr/testify/assert"
+)
+
+func TestRegistration(t *testing.T) {
+	t.Parallel()
+
+	collectors := []prometheus.Collector{
+		prometheus.NewCounter(prometheus.CounterOpts{
+			Namespace: "signaling",
+			Subsystem: "test",
+			Name:      "value_total",
+			Help:      "Total value.",
+		}),
+		prometheus.NewGaugeVec(prometheus.GaugeOpts{
+			Namespace: "signaling",
+			Subsystem: "test",
+			Name:      "value",
+			Help:      "Current value.",
+		}, []string{"foo", "bar"}),
+	}
+	// Can unregister without previous registration
+	UnregisterAll(collectors...)
+	RegisterAll(collectors...)
+	// Can register multiple times
+	RegisterAll(collectors...)
+	UnregisterAll(collectors...)
+}
+
+func TestRegistrationError(t *testing.T) {
+	t.Parallel()
+
+	defer func() {
+		value := recover()
+		if err, ok := value.(error); assert.True(t, ok) {
+			assert.ErrorContains(t, err, "is not a valid metric name")
+		}
+	}()
+
+	RegisterAll(prometheus.NewCounter(prometheus.CounterOpts{}))
+}