Subscriptions: Add List.Clone

exchanges/subscription/list.go

@@ -46,6 +46,15 @@ func (l List) GroupPairs() (n List) {
 	return s.List()
 }
 
+// Clone returns a deep clone of the List
+func (l List) Clone() List {
+	n := make(List, len(l))
+	for i, s := range l {
+		n[i] = s.Clone()
+	}
+	return n
+}
+
 // QualifiedChannels returns a sorted list of all the qualified Channels in the list
 func (l List) QualifiedChannels() []string {
 	c := make([]string, len(l))

exchanges/subscription/list_test.go

@@ -91,3 +91,12 @@ func TestAssetPairs(t *testing.T) {
 		assert.ErrorIs(t, err, expErr, "Should error correctly on GetPairFormat")
 	}
 }
+
+func TestListClone(t *testing.T) {
+	t.Parallel()
+	l := List{{Channel: TickerChannel}, {Channel: OrderbookChannel}}
+	n := l.Clone()
+	assert.NotSame(t, n, l, "Slices must not be the same")
+	require.NotEmpty(t, n, "List must not be empty")
+	assert.NotSame(t, n[0], l[0], "Subscriptions must be cloned")
+}