getAttributes() (#41)

Signed-off-by: Jason Madigan <jason@jasonmadigan.com>

edge.go

@@ -71,3 +71,8 @@ func (e Edge) From() Node {
 func (e Edge) To() Node {
 	return e.to
 }
+
+// Returns attributes for this edge
+func (e Edge) GetAttributes() map[string]interface{} {
+	return e.AttributesMap.GetAttributes()
+}

edge_test.go

@@ -119,3 +119,17 @@ func TestNonStringAttribute(t *testing.T) {
 		t.Errorf("got [%v] want [%v]", got, want)
 	}
 }
+
+func TestEdgeGetAttributes(t *testing.T) {
+	di := NewGraph(Directed)
+	n1 := di.Node("A")
+	n2 := di.Node("B")
+	e := di.Edge(n1, n2).Label("edge-label").Attr("foo", "bar")
+	attrs := e.GetAttributes()
+	if v, ok := attrs["label"]; !ok || v != "edge-label" {
+		t.Errorf("expected label=edge-label, got %v", attrs)
+	}
+	if v, ok := attrs["foo"]; !ok || v != "bar" {
+		t.Errorf("expected foo=bar, got %v", attrs)
+	}
+}

graph.go

@@ -418,3 +418,12 @@ func (g *Graph) EdgesMap() map[string][]Edge {
 func (g *Graph) HasNode(n Node) bool {
 	return g == n.graph
 }
+
+// GetAttributes returns a copy of the attributes
+func (am *AttributesMap) GetAttributes() map[string]interface{} {
+	copyMap := make(map[string]interface{}, len(am.attributes))
+	for k, v := range am.attributes {
+		copyMap[k] = v
+	}
+	return copyMap
+}

graph_test.go

@@ -414,3 +414,15 @@ func TestFindNodeWithLabel(t *testing.T) {
 		t.Fail()
 	}
 }
+
+func TestNodeGetAttributesCopy(t *testing.T) {
+	di := NewGraph(Directed)
+	n := di.Node("A")
+	n.Attr("foo", "bar")
+	attrs := n.GetAttributes()
+	attrs["foo"] = "bar"
+	attrs2 := n.GetAttributes()
+	if v, ok := attrs2["foo"]; !ok || v != "bar" {
+		t.Errorf("expected foo=bar, got %v", attrs2)
+	}
+}