Merge branch '#90'

Author: zhengchun

node.go

@@ -172,6 +172,55 @@ func AddAttr(n *Node, key, val string) {
 	n.Attr = append(n.Attr, attr)
 }
 
+// SetAttr allows an attribute value with the specified name to be changed.
+// If the attribute did not previously exist, it will be created.
+func (n *Node) SetAttr(key, value string) {
+	if i := strings.Index(key, ":"); i > 0 {
+		space := key[:i]
+		local := key[i+1:]
+		for idx := 0; idx < len(n.Attr); idx++ {
+			if n.Attr[idx].Name.Space == space && n.Attr[idx].Name.Local == local {
+				n.Attr[idx].Value = value
+				return
+			}
+		}
+
+		AddAttr(n, key, value)
+	} else {
+		for idx := 0; idx < len(n.Attr); idx++ {
+			if n.Attr[idx].Name.Local == key {
+				n.Attr[idx].Value = value
+				return
+			}
+		}
+
+		AddAttr(n, key, value)
+	}
+}
+
+// RemoveAttr removes the attribute with the specified name.
+func (n *Node) RemoveAttr(key string) {
+	removeIdx := -1
+	if i := strings.Index(key, ":"); i > 0 {
+		space := key[:i]
+		local := key[i+1:]
+		for idx := 0; idx < len(n.Attr); idx++ {
+			if n.Attr[idx].Name.Space == space && n.Attr[idx].Name.Local == local {
+				removeIdx = idx
+			}
+		}
+	} else {
+		for idx := 0; idx < len(n.Attr); idx++ {
+			if n.Attr[idx].Name.Local == key {
+				removeIdx = idx
+			}
+		}
+	}
+	if removeIdx != -1 {
+		n.Attr = append(n.Attr[:removeIdx], n.Attr[removeIdx+1:]...)
+	}
+}
+
 // AddChild adds a new node 'n' to a node 'parent' as its last child.
 func AddChild(parent, n *Node) {
 	n.Parent = parent

node_test.go

@@ -147,6 +147,94 @@ func TestAddAttr(t *testing.T) {
 	}
 }
 
+func TestSetAttr(t *testing.T) {
+	for _, test := range []struct {
+		name     string
+		n        *Node
+		key      string
+		val      string
+		expected string
+	}{
+		{
+			name:     "node has no existing attr",
+			n:        &Node{Type: AttributeNode},
+			key:      "ns:k1",
+			val:      "v1",
+			expected: `< ns:k1="v1"></>`,
+		},
+		{
+			name:     "node has an existing attr, overwriting",
+			n:        &Node{Type: AttributeNode, Attr: []Attr{{Name: xml.Name{Space: "ns", Local: "k1"}, Value: "v1"}}},
+			key:      "ns:k1",
+			val:      "v2",
+			expected: `< ns:k1="v2"></>`,
+		},
+		{
+			name:     "node has no existing attr, no ns",
+			n:        &Node{Type: AttributeNode},
+			key:      "k1",
+			val:      "v1",
+			expected: `< k1="v1"></>`,
+		},
+		{
+			name:     "node has an existing attr, no ns, overwriting",
+			n:        &Node{Type: AttributeNode, Attr: []Attr{{Name: xml.Name{Local: "k1"}, Value: "v1"}}},
+			key:      "k1",
+			val:      "v2",
+			expected: `< k1="v2"></>`,
+		},
+
+	} {
+
+		t.Run(test.name, func(t *testing.T) {
+			test.n.SetAttr(test.key, test.val)
+			testValue(t, test.n.OutputXML(true), test.expected)
+		})
+	}
+}
+
+func TestRemoveAttr(t *testing.T) {
+	for _, test := range []struct {
+		name     string
+		n        *Node
+		key      string
+		expected string
+	}{
+		{
+			name:     "node has no existing attr",
+			n:        &Node{Type: AttributeNode},
+			key:      "ns:k1",
+			expected: `<></>`,
+		},
+		{
+			name:     "node has an existing attr, overwriting",
+			n:        &Node{Type: AttributeNode, Attr: []Attr{{Name: xml.Name{Space: "ns", Local: "k1"}, Value: "v1"}}},
+			key:      "ns:k1",
+			expected: `<></>`,
+		},
+		{
+			name:     "node has no existing attr, no ns",
+			n:        &Node{Type: AttributeNode},
+			key:      "k1",
+			expected: `<></>`,
+		},
+		{
+			name:     "node has an existing attr, no ns, overwriting",
+			n:        &Node{Type: AttributeNode, Attr: []Attr{{Name: xml.Name{Local: "k1"}, Value: "v1"}}},
+			key:      "k1",
+			expected: `<></>`,
+		},
+
+	} {
+
+		t.Run(test.name, func(t *testing.T) {
+			test.n.RemoveAttr(test.key)
+			testValue(t, test.n.OutputXML(true), test.expected)
+		})
+	}
+}
+
+
 func TestRemoveFromTree(t *testing.T) {
 	xml := `<?procinst?>
 		<!--comment-->