[#311] control: Cover StableMarshal methods with unit tests

Signed-off-by: Leonard Lyubich <leonard@nspcc.ru>

pkg/services/control/common_test.go

@@ -0,0 +1,36 @@
+package control_test
+
+import (
+	"crypto/rand"
+	"testing"
+
+	"github.com/mr-tron/base58"
+	"github.com/stretchr/testify/require"
+	"google.golang.org/protobuf/proto"
+)
+
+type protoMessage interface {
+	StableMarshal([]byte) ([]byte, error)
+	proto.Message
+}
+
+func testStableMarshal(t *testing.T, m1, m2 protoMessage, cmp func(m1, m2 protoMessage) bool) {
+	data, err := m1.StableMarshal(nil)
+	require.NoError(t, err)
+
+	require.NoError(t, proto.Unmarshal(data, m2))
+
+	require.True(t, cmp(m1, m2))
+}
+
+func testData(sz int) []byte {
+	d := make([]byte, sz)
+
+	_, _ = rand.Read(d)
+
+	return d
+}
+
+func testString() string {
+	return base58.Encode(testData(10))
+}