add metrics test

internal/p2p/metrics_test.go

@@ -0,0 +1,19 @@
+package p2p
+
+import (
+	"testing"
+
+	"github.com/stretchr/testify/assert"
+	"github.com/tendermint/tendermint/proto/tendermint/statesync"
+)
+
+func TestValueToMetricsLabel(t *testing.T) {
+	m := NopMetrics()
+	r := &statesync.ParamsRequest{}
+	str := m.ValueToMetricLabel(r)
+	assert.Equal(t, "statesync_ParamsRequest", str)
+
+	// subsequent calls to the function should produce the same result
+	str = m.ValueToMetricLabel(r)
+	assert.Equal(t, "statesync_ParamsRequest", str)
+}