Merge pull request #6 from arduino/scerza/fix-subtree-index-extract

Fix `ExtractSubIndexLists` returning a list containing a single empty string if root property is not found

Author: silvanocerza

properties.go

@@ -636,7 +636,9 @@ func (m *Map) ExtractSubIndexLists(root string) []string {
 
 	// if there are no subindexed then return the whole "roox.xxx" subtree
 	if !haveIndexedProperties {
-		res = append(res, m.Get(root))
+		if value, ok := m.GetOk(root); ok {
+			res = append(res, value)
+		}
 	}
 
 	return res

properties_test.go

@@ -356,6 +356,7 @@ func TestExtractSubIndexLists(t *testing.T) {
 		"quattro.discovery.required":   "itemA",
 		"quattro.discovery.required.1": "itemB",
 		"quattro.discovery.required.2": "itemC",
+		"cinque.discovery.something":   "itemX",
 	}
 	m := NewFromHashmap(data)
 
@@ -379,4 +380,7 @@ func TestExtractSubIndexLists(t *testing.T) {
 	require.Len(t, s4, 2)
 	require.Equal(t, s4[0], "itemB")
 	require.Equal(t, s4[1], "itemC")
+
+	s5 := m.ExtractSubIndexLists("cinque.discovery.required")
+	require.Len(t, s5, 0)
 }