Addressed the comments and fixed the tests.

test/utils/prune.go

@@ -0,0 +1,30 @@
+package utils
+
+import (
+	"github.com/weaveworks/scope/report"
+)
+
+// Prune returns a copy of the Nodes with all information not strictly
+// necessary for rendering nodes and edges in the UI cut away.
+func Prune(nodes report.Nodes) report.Nodes {
+	result := report.Nodes{}
+	for id, node := range nodes {
+		result[id] = PruneNode(node)
+	}
+	return result
+}
+
+// PruneNode returns a copy of the Node with all information not strictly
+// necessary for rendering nodes and edges stripped away. Specifically, that
+// means cutting out parts of the Node.
+func PruneNode(node report.Node) report.Node {
+	prunedChildren := report.MakeNodeSet()
+	node.Children.ForEach(func(child report.Node) {
+		prunedChildren = prunedChildren.Add(PruneNode(child))
+	})
+	return report.MakeNode(
+		node.ID).
+		WithTopology(node.Topology).
+		WithAdjacent(node.Adjacency.Copy()...).
+		WithChildren(prunedChildren)
+}