diff --git a/dag/dag_test.go b/dag/dag_test.go
index ae2c2387e..90a9f75c6 100644
--- a/dag/dag_test.go
+++ b/dag/dag_test.go
@@ -340,7 +340,7 @@ func BenchmarkDAG(b *testing.B) {
 		// layer B
 		for i := 0; i < count; i++ {
 			B := fmt.Sprintf("B%d", i)
-			g.Add(fmt.Sprintf(B))
+			g.Add(B)
 			for j := 0; j < count; j++ {
 				g.Connect(BasicEdge(B, fmt.Sprintf("A%d", j)))
 			}
@@ -349,7 +349,7 @@ func BenchmarkDAG(b *testing.B) {
 		// layer C
 		for i := 0; i < count; i++ {
 			c := fmt.Sprintf("C%d", i)
-			g.Add(fmt.Sprintf(c))
+			g.Add(c)
 			for j := 0; j < count; j++ {
 				// connect them to previous layers so we have something that requires reduction
 				g.Connect(BasicEdge(c, fmt.Sprintf("A%d", j)))
@@ -360,7 +360,7 @@ func BenchmarkDAG(b *testing.B) {
 		// layer D
 		for i := 0; i < count; i++ {
 			d := fmt.Sprintf("D%d", i)
-			g.Add(fmt.Sprintf(d))
+			g.Add(d)
 			for j := 0; j < count; j++ {
 				g.Connect(BasicEdge(d, fmt.Sprintf("A%d", j)))
 				g.Connect(BasicEdge(d, fmt.Sprintf("B%d", j)))
diff --git a/dag/graph.go b/dag/graph.go
index 1d0544354..222ac0786 100644
--- a/dag/graph.go
+++ b/dag/graph.go
@@ -337,7 +337,7 @@ func VertexName(raw Vertex) string {
 	case NamedVertex:
 		return v.Name()
 	case fmt.Stringer:
-		return fmt.Sprintf("%s", v)
+		return v.String()
 	default:
 		return fmt.Sprintf("%v", v)
 	}
diff --git a/dag/marshal.go b/dag/marshal.go
index 0ad45e8cb..0ba52152f 100644
--- a/dag/marshal.go
+++ b/dag/marshal.go
@@ -7,18 +7,6 @@ import (
 	"strconv"
 )
 
-const (
-	typeOperation             = "Operation"
-	typeTransform             = "Transform"
-	typeWalk                  = "Walk"
-	typeDepthFirstWalk        = "DepthFirstWalk"
-	typeReverseDepthFirstWalk = "ReverseDepthFirstWalk"
-	typeTransitiveReduction   = "TransitiveReduction"
-	typeEdgeInfo              = "EdgeInfo"
-	typeVertexInfo            = "VertexInfo"
-	typeVisitInfo             = "VisitInfo"
-)
-
 // the marshal* structs are for serialization of the graph data.
 type marshalGraph struct {
 	// Type is always "Graph", for identification as a top level object in the
@@ -49,36 +37,6 @@ type marshalGraph struct {
 	Cycles [][]*marshalVertex `json:",omitempty"`
 }
 
-// The add, remove, connect, removeEdge methods mirror the basic Graph
-// manipulations to reconstruct a marshalGraph from a debug log.
-func (g *marshalGraph) add(v *marshalVertex) {
-	g.Vertices = append(g.Vertices, v)
-	sort.Sort(vertices(g.Vertices))
-}
-
-func (g *marshalGraph) remove(v *marshalVertex) {
-	for i, existing := range g.Vertices {
-		if v.ID == existing.ID {
-			g.Vertices = append(g.Vertices[:i], g.Vertices[i+1:]...)
-			return
-		}
-	}
-}
-
-func (g *marshalGraph) connect(e *marshalEdge) {
-	g.Edges = append(g.Edges, e)
-	sort.Sort(edges(g.Edges))
-}
-
-func (g *marshalGraph) removeEdge(e *marshalEdge) {
-	for i, existing := range g.Edges {
-		if e.Source == existing.Source && e.Target == existing.Target {
-			g.Edges = append(g.Edges[:i], g.Edges[i+1:]...)
-			return
-		}
-	}
-}
-
 func (g *marshalGraph) vertexByID(id string) *marshalVertex {
 	for _, v := range g.Vertices {
 		if id == v.ID {
diff --git a/dag/set.go b/dag/set.go
index c5c1af120..fc16e801b 100644
--- a/dag/set.go
+++ b/dag/set.go
@@ -56,15 +56,13 @@ func (s Set) Intersection(other Set) Set {
 // other doesn't.
 func (s Set) Difference(other Set) Set {
 	result := make(Set)
-	if s != nil {
-		for k, v := range s {
-			var ok bool
-			if other != nil {
-				_, ok = other[k]
-			}
-			if !ok {
-				result.Add(v)
-			}
+	for k, v := range s {
+		var ok bool
+		if other != nil {
+			_, ok = other[k]
+		}
+		if !ok {
+			result.Add(v)
 		}
 	}
 
diff --git a/dag/walk.go b/dag/walk.go
index f9fdf2dfc..0f2d212be 100644
--- a/dag/walk.go
+++ b/dag/walk.go
@@ -106,11 +106,6 @@ type walkerVertex struct {
 	depsCancelCh chan struct{}
 }
 
-// errWalkUpstream is used in the errMap of a walk to note that an upstream
-// dependency failed so this vertex wasn't run. This is not shown in the final
-// user-returned error.
-var errWalkUpstream = errors.New("upstream dependency failed")
-
 // Wait waits for the completion of the walk and returns diagnostics describing
 // any problems that arose. Update should be called to populate the walk with
 // vertices and edges prior to calling this.
diff --git a/digraph/basic.go b/digraph/basic.go
deleted file mode 100644
index 8dc76838d..000000000
--- a/digraph/basic.go
+++ /dev/null
@@ -1,89 +0,0 @@
-package digraph
-
-import (
-	"fmt"
-	"strings"
-)
-
-// BasicNode is a digraph Node that has a name and out edges
-type BasicNode struct {
-	Name      string
-	NodeEdges []Edge
-}
-
-func (b *BasicNode) Edges() []Edge {
-	return b.NodeEdges
-}
-
-func (b *BasicNode) AddEdge(edge Edge) {
-	b.NodeEdges = append(b.NodeEdges, edge)
-}
-
-func (b *BasicNode) String() string {
-	if b.Name == "" {
-		return "Node"
-	}
-	return fmt.Sprintf("%v", b.Name)
-}
-
-// BasicEdge is a digraph Edge that has a name, head and tail
-type BasicEdge struct {
-	Name     string
-	EdgeHead *BasicNode
-	EdgeTail *BasicNode
-}
-
-func (b *BasicEdge) Head() Node {
-	return b.EdgeHead
-}
-
-// Tail returns the end point of the Edge
-func (b *BasicEdge) Tail() Node {
-	return b.EdgeTail
-}
-
-func (b *BasicEdge) String() string {
-	if b.Name == "" {
-		return "Edge"
-	}
-	return fmt.Sprintf("%v", b.Name)
-}
-
-// ParseBasic is used to parse a string in the format of:
-// a -> b ; edge name
-// b -> c
-// Into a series of basic node and basic edges
-func ParseBasic(s string) map[string]*BasicNode {
-	lines := strings.Split(s, "\n")
-	nodes := make(map[string]*BasicNode)
-	for _, line := range lines {
-		var edgeName string
-		if idx := strings.Index(line, ";"); idx >= 0 {
-			edgeName = strings.Trim(line[idx+1:], " \t\r\n")
-			line = line[:idx]
-		}
-		parts := strings.SplitN(line, "->", 2)
-		if len(parts) != 2 {
-			continue
-		}
-		head_name := strings.Trim(parts[0], " \t\r\n")
-		tail_name := strings.Trim(parts[1], " \t\r\n")
-		head := nodes[head_name]
-		if head == nil {
-			head = &BasicNode{Name: head_name}
-			nodes[head_name] = head
-		}
-		tail := nodes[tail_name]
-		if tail == nil {
-			tail = &BasicNode{Name: tail_name}
-			nodes[tail_name] = tail
-		}
-		edge := &BasicEdge{
-			Name:     edgeName,
-			EdgeHead: head,
-			EdgeTail: tail,
-		}
-		head.AddEdge(edge)
-	}
-	return nodes
-}
diff --git a/digraph/basic_test.go b/digraph/basic_test.go
deleted file mode 100644
index 20584b09b..000000000
--- a/digraph/basic_test.go
+++ /dev/null
@@ -1,53 +0,0 @@
-package digraph
-
-import (
-	"fmt"
-	"testing"
-)
-
-func TestParseBasic(t *testing.T) {
-	spec := `a -> b ; first
-b -> c ; second
-b -> d ; third
-z -> a`
-	nodes := ParseBasic(spec)
-	if len(nodes) != 5 {
-		t.Fatalf("bad: %v", nodes)
-	}
-
-	a := nodes["a"]
-	if a.Name != "a" {
-		t.Fatalf("bad: %v", a)
-	}
-	aEdges := a.Edges()
-	if len(aEdges) != 1 {
-		t.Fatalf("bad: %v", a.Edges())
-	}
-	if fmt.Sprintf("%v", aEdges[0]) != "first" {
-		t.Fatalf("bad: %v", aEdges[0])
-	}
-
-	b := nodes["b"]
-	if len(b.Edges()) != 2 {
-		t.Fatalf("bad: %v", b.Edges())
-	}
-
-	c := nodes["c"]
-	if len(c.Edges()) != 0 {
-		t.Fatalf("bad: %v", c.Edges())
-	}
-
-	d := nodes["d"]
-	if len(d.Edges()) != 0 {
-		t.Fatalf("bad: %v", d.Edges())
-	}
-
-	z := nodes["z"]
-	zEdges := z.Edges()
-	if len(zEdges) != 1 {
-		t.Fatalf("bad: %v", z.Edges())
-	}
-	if fmt.Sprintf("%v", zEdges[0]) != "Edge" {
-		t.Fatalf("bad: %v", zEdges[0])
-	}
-}
diff --git a/digraph/digraph.go b/digraph/digraph.go
deleted file mode 100644
index ccf311170..000000000
--- a/digraph/digraph.go
+++ /dev/null
@@ -1,34 +0,0 @@
-package digraph
-
-// Digraph is used to represent a Directed Graph. This means
-// we have a set of nodes, and a set of edges which are directed
-// from a source and towards a destination
-type Digraph interface {
-	// Nodes provides all the nodes in the graph
-	Nodes() []Node
-
-	// Sources provides all the source nodes in the graph
-	Sources() []Node
-
-	// Sinks provides all the sink nodes in the graph
-	Sinks() []Node
-
-	// Transpose reverses the edge directions and returns
-	// a new Digraph
-	Transpose() Digraph
-}
-
-// Node represents a vertex in a Digraph
-type Node interface {
-	// Edges returns the out edges for a given nod
-	Edges() []Edge
-}
-
-// Edge represents a directed edge in a Digraph
-type Edge interface {
-	// Head returns the start point of the Edge
-	Head() Node
-
-	// Tail returns the end point of the Edge
-	Tail() Node
-}
diff --git a/digraph/graphviz.go b/digraph/graphviz.go
deleted file mode 100644
index db6952ebb..000000000
--- a/digraph/graphviz.go
+++ /dev/null
@@ -1,28 +0,0 @@
-package digraph
-
-import (
-	"fmt"
-	"io"
-)
-
-// WriteDot is used to emit a GraphViz compatible definition
-// for a directed graph. It can be used to dump a .dot file.
-func WriteDot(w io.Writer, nodes []Node) error {
-	w.Write([]byte("digraph {\n"))
-	defer w.Write([]byte("}\n"))
-
-	for _, n := range nodes {
-		nodeLine := fmt.Sprintf("\t\"%s\";\n", n)
-
-		w.Write([]byte(nodeLine))
-
-		for _, edge := range n.Edges() {
-			target := edge.Tail()
-			line := fmt.Sprintf("\t\"%s\" -> \"%s\" [label=\"%s\"];\n",
-				n, target, edge)
-			w.Write([]byte(line))
-		}
-	}
-
-	return nil
-}
diff --git a/digraph/graphviz_test.go b/digraph/graphviz_test.go
deleted file mode 100644
index 69e4ebb89..000000000
--- a/digraph/graphviz_test.go
+++ /dev/null
@@ -1,64 +0,0 @@
-package digraph
-
-import (
-	"bytes"
-	"strings"
-	"testing"
-)
-
-func TestWriteDot(t *testing.T) {
-	nodes := ParseBasic(`a -> b ; foo
-a -> c
-b -> d
-b -> e
-`)
-	var nlist []Node
-	for _, n := range nodes {
-		nlist = append(nlist, n)
-	}
-
-	buf := bytes.NewBuffer(nil)
-	if err := WriteDot(buf, nlist); err != nil {
-		t.Fatalf("err: %s", err)
-	}
-
-	actual := strings.TrimSpace(string(buf.Bytes()))
-	expected := strings.TrimSpace(writeDotStr)
-
-	actualLines := strings.Split(actual, "\n")
-	expectedLines := strings.Split(expected, "\n")
-
-	if actualLines[0] != expectedLines[0] ||
-		actualLines[len(actualLines)-1] != expectedLines[len(expectedLines)-1] ||
-		len(actualLines) != len(expectedLines) {
-		t.Fatalf("bad: %s", actual)
-	}
-
-	count := 0
-	for _, el := range expectedLines[1 : len(expectedLines)-1] {
-		for _, al := range actualLines[1 : len(actualLines)-1] {
-			if el == al {
-				count++
-				break
-			}
-		}
-	}
-
-	if count != len(expectedLines)-2 {
-		t.Fatalf("bad: %s", actual)
-	}
-}
-
-const writeDotStr = `
-digraph {
-	"a";
-	"a" -> "b" [label="foo"];
-	"a" -> "c" [label="Edge"];
-	"b";
-	"b" -> "d" [label="Edge"];
-	"b" -> "e" [label="Edge"];
-	"c";
-	"d";
-	"e";
-}
-`
diff --git a/digraph/tarjan.go b/digraph/tarjan.go
deleted file mode 100644
index 2298610ed..000000000
--- a/digraph/tarjan.go
+++ /dev/null
@@ -1,111 +0,0 @@
-package digraph
-
-// sccAcct is used ot pass around accounting information for
-// the StronglyConnectedComponents algorithm
-type sccAcct struct {
-	ExcludeSingle bool
-	NextIndex     int
-	NodeIndex     map[Node]int
-	Stack         []Node
-	SCC           [][]Node
-}
-
-// visit assigns an index and pushes a node onto the stack
-func (s *sccAcct) visit(n Node) int {
-	idx := s.NextIndex
-	s.NodeIndex[n] = idx
-	s.NextIndex++
-	s.push(n)
-	return idx
-}
-
-// push adds a node to the stack
-func (s *sccAcct) push(n Node) {
-	s.Stack = append(s.Stack, n)
-}
-
-// pop removes a node from the stack
-func (s *sccAcct) pop() Node {
-	n := len(s.Stack)
-	if n == 0 {
-		return nil
-	}
-	node := s.Stack[n-1]
-	s.Stack = s.Stack[:n-1]
-	return node
-}
-
-// inStack checks if a node is in the stack
-func (s *sccAcct) inStack(needle Node) bool {
-	for _, n := range s.Stack {
-		if n == needle {
-			return true
-		}
-	}
-	return false
-}
-
-// StronglyConnectedComponents implements Tarjan's algorithm to
-// find all the strongly connected components in a graph. This can
-// be used to detected any cycles in a graph, as well as which nodes
-// partipate in those cycles. excludeSingle is used to exclude strongly
-// connected components of size one.
-func StronglyConnectedComponents(nodes []Node, excludeSingle bool) [][]Node {
-	acct := sccAcct{
-		ExcludeSingle: excludeSingle,
-		NextIndex:     1,
-		NodeIndex:     make(map[Node]int, len(nodes)),
-	}
-	for _, node := range nodes {
-		// Recurse on any non-visited nodes
-		if acct.NodeIndex[node] == 0 {
-			stronglyConnected(&acct, node)
-		}
-	}
-	return acct.SCC
-}
-
-func stronglyConnected(acct *sccAcct, node Node) int {
-	// Initial node visit
-	index := acct.visit(node)
-	minIdx := index
-
-	for _, edge := range node.Edges() {
-		target := edge.Tail()
-		targetIdx := acct.NodeIndex[target]
-
-		// Recurse on successor if not yet visited
-		if targetIdx == 0 {
-			minIdx = min(minIdx, stronglyConnected(acct, target))
-
-		} else if acct.inStack(target) {
-			// Check if the node is in the stack
-			minIdx = min(minIdx, targetIdx)
-		}
-	}
-
-	// Pop the strongly connected components off the stack if
-	// this is a root node
-	if index == minIdx {
-		var scc []Node
-		for {
-			n := acct.pop()
-			scc = append(scc, n)
-			if n == node {
-				break
-			}
-		}
-		if !(acct.ExcludeSingle && len(scc) == 1) {
-			acct.SCC = append(acct.SCC, scc)
-		}
-	}
-
-	return minIdx
-}
-
-func min(a, b int) int {
-	if a <= b {
-		return a
-	}
-	return b
-}
diff --git a/digraph/tarjan_test.go b/digraph/tarjan_test.go
deleted file mode 100644
index d14a75ec8..000000000
--- a/digraph/tarjan_test.go
+++ /dev/null
@@ -1,82 +0,0 @@
-package digraph
-
-import (
-	"reflect"
-	"sort"
-	"testing"
-)
-
-func TestStronglyConnectedComponents(t *testing.T) {
-	nodes := ParseBasic(`a -> b
-a -> c
-b -> c
-c -> b
-c -> d
-d -> e`)
-	var nlist []Node
-	for _, n := range nodes {
-		nlist = append(nlist, n)
-	}
-
-	sccs := StronglyConnectedComponents(nlist, false)
-	if len(sccs) != 4 {
-		t.Fatalf("bad: %v", sccs)
-	}
-
-	sccs = StronglyConnectedComponents(nlist, true)
-	if len(sccs) != 1 {
-		t.Fatalf("bad: %v", sccs)
-	}
-
-	cycle := sccs[0]
-	if len(cycle) != 2 {
-		t.Fatalf("bad: %v", sccs)
-	}
-
-	cycleNodes := make([]string, len(cycle))
-	for i, c := range cycle {
-		cycleNodes[i] = c.(*BasicNode).Name
-	}
-	sort.Strings(cycleNodes)
-
-	expected := []string{"b", "c"}
-	if !reflect.DeepEqual(cycleNodes, expected) {
-		t.Fatalf("bad: %#v", cycleNodes)
-	}
-}
-
-func TestStronglyConnectedComponents2(t *testing.T) {
-	nodes := ParseBasic(`a -> b
-a -> c
-b -> d
-b -> e
-c -> f
-c -> g
-g -> a
-`)
-	var nlist []Node
-	for _, n := range nodes {
-		nlist = append(nlist, n)
-	}
-
-	sccs := StronglyConnectedComponents(nlist, true)
-	if len(sccs) != 1 {
-		t.Fatalf("bad: %v", sccs)
-	}
-
-	cycle := sccs[0]
-	if len(cycle) != 3 {
-		t.Fatalf("bad: %v", sccs)
-	}
-
-	cycleNodes := make([]string, len(cycle))
-	for i, c := range cycle {
-		cycleNodes[i] = c.(*BasicNode).Name
-	}
-	sort.Strings(cycleNodes)
-
-	expected := []string{"a", "c", "g"}
-	if !reflect.DeepEqual(cycleNodes, expected) {
-		t.Fatalf("bad: %#v", cycleNodes)
-	}
-}
diff --git a/digraph/util.go b/digraph/util.go
deleted file mode 100644
index 96a09ed82..000000000
--- a/digraph/util.go
+++ /dev/null
@@ -1,113 +0,0 @@
-package digraph
-
-// DepthFirstWalk performs a depth-first traversal of the nodes
-// that can be reached from the initial input set. The callback is
-// invoked for each visited node, and may return false to prevent
-// vising any children of the current node
-func DepthFirstWalk(node Node, cb func(n Node) bool) {
-	frontier := []Node{node}
-	seen := make(map[Node]struct{})
-	for len(frontier) > 0 {
-		// Pop the current node
-		n := len(frontier)
-		current := frontier[n-1]
-		frontier = frontier[:n-1]
-
-		// Check for potential cycle
-		if _, ok := seen[current]; ok {
-			continue
-		}
-		seen[current] = struct{}{}
-
-		// Visit with the callback
-		if !cb(current) {
-			continue
-		}
-
-		// Add any new edges to visit, in reverse order
-		edges := current.Edges()
-		for i := len(edges) - 1; i >= 0; i-- {
-			frontier = append(frontier, edges[i].Tail())
-		}
-	}
-}
-
-// FilterDegree returns only the nodes with the desired
-// degree. This can be used with OutDegree or InDegree
-func FilterDegree(degree int, degrees map[Node]int) []Node {
-	var matching []Node
-	for n, d := range degrees {
-		if d == degree {
-			matching = append(matching, n)
-		}
-	}
-	return matching
-}
-
-// InDegree is used to compute the in-degree of nodes
-func InDegree(nodes []Node) map[Node]int {
-	degree := make(map[Node]int, len(nodes))
-	for _, n := range nodes {
-		if _, ok := degree[n]; !ok {
-			degree[n] = 0
-		}
-		for _, e := range n.Edges() {
-			degree[e.Tail()]++
-		}
-	}
-	return degree
-}
-
-// OutDegree is used to compute the in-degree of nodes
-func OutDegree(nodes []Node) map[Node]int {
-	degree := make(map[Node]int, len(nodes))
-	for _, n := range nodes {
-		degree[n] = len(n.Edges())
-	}
-	return degree
-}
-
-// Sinks is used to get the nodes with out-degree of 0
-func Sinks(nodes []Node) []Node {
-	return FilterDegree(0, OutDegree(nodes))
-}
-
-// Sources is used to get the nodes with in-degree of 0
-func Sources(nodes []Node) []Node {
-	return FilterDegree(0, InDegree(nodes))
-}
-
-// Unreachable starts at a given start node, performs
-// a DFS from there, and returns the set of unreachable nodes.
-func Unreachable(start Node, nodes []Node) []Node {
-	// DFS from the start ndoe
-	frontier := []Node{start}
-	seen := make(map[Node]struct{})
-	for len(frontier) > 0 {
-		// Pop the current node
-		n := len(frontier)
-		current := frontier[n-1]
-		frontier = frontier[:n-1]
-
-		// Check for potential cycle
-		if _, ok := seen[current]; ok {
-			continue
-		}
-		seen[current] = struct{}{}
-
-		// Add any new edges to visit, in reverse order
-		edges := current.Edges()
-		for i := len(edges) - 1; i >= 0; i-- {
-			frontier = append(frontier, edges[i].Tail())
-		}
-	}
-
-	// Check for any unseen nodes
-	var unseen []Node
-	for _, node := range nodes {
-		if _, ok := seen[node]; !ok {
-			unseen = append(unseen, node)
-		}
-	}
-	return unseen
-}
diff --git a/digraph/util_test.go b/digraph/util_test.go
deleted file mode 100644
index e6d359991..000000000
--- a/digraph/util_test.go
+++ /dev/null
@@ -1,233 +0,0 @@
-package digraph
-
-import (
-	"reflect"
-	"testing"
-)
-
-func TestDepthFirstWalk(t *testing.T) {
-	nodes := ParseBasic(`a -> b
-a -> c
-a -> d
-b -> e
-d -> f
-e -> a ; cycle`)
-	root := nodes["a"]
-	expected := []string{
-		"a",
-		"b",
-		"e",
-		"c",
-		"d",
-		"f",
-	}
-	index := 0
-	DepthFirstWalk(root, func(n Node) bool {
-		name := n.(*BasicNode).Name
-		if expected[index] != name {
-			t.Fatalf("expected: %v, got %v", expected[index], name)
-		}
-		index++
-		return true
-	})
-}
-
-func TestInDegree(t *testing.T) {
-	nodes := ParseBasic(`a -> b
-a -> c
-a -> d
-b -> e
-c -> e
-d -> f`)
-	var nlist []Node
-	for _, n := range nodes {
-		nlist = append(nlist, n)
-	}
-
-	expected := map[string]int{
-		"a": 0,
-		"b": 1,
-		"c": 1,
-		"d": 1,
-		"e": 2,
-		"f": 1,
-	}
-	indegree := InDegree(nlist)
-	for n, d := range indegree {
-		name := n.(*BasicNode).Name
-		exp := expected[name]
-		if exp != d {
-			t.Fatalf("Expected %d for %s, got %d",
-				exp, name, d)
-		}
-	}
-}
-
-func TestOutDegree(t *testing.T) {
-	nodes := ParseBasic(`a -> b
-a -> c
-a -> d
-b -> e
-c -> e
-d -> f`)
-	var nlist []Node
-	for _, n := range nodes {
-		nlist = append(nlist, n)
-	}
-
-	expected := map[string]int{
-		"a": 3,
-		"b": 1,
-		"c": 1,
-		"d": 1,
-		"e": 0,
-		"f": 0,
-	}
-	outDegree := OutDegree(nlist)
-	for n, d := range outDegree {
-		name := n.(*BasicNode).Name
-		exp := expected[name]
-		if exp != d {
-			t.Fatalf("Expected %d for %s, got %d",
-				exp, name, d)
-		}
-	}
-}
-
-func TestSinks(t *testing.T) {
-	nodes := ParseBasic(`a -> b
-a -> c
-a -> d
-b -> e
-c -> e
-d -> f`)
-	var nlist []Node
-	for _, n := range nodes {
-		nlist = append(nlist, n)
-	}
-
-	sinks := Sinks(nlist)
-
-	var haveE, haveF bool
-	for _, n := range sinks {
-		name := n.(*BasicNode).Name
-		switch name {
-		case "e":
-			haveE = true
-		case "f":
-			haveF = true
-		}
-	}
-	if !haveE || !haveF {
-		t.Fatalf("missing sink")
-	}
-}
-
-func TestSources(t *testing.T) {
-	nodes := ParseBasic(`a -> b
-a -> c
-a -> d
-b -> e
-c -> e
-d -> f
-x -> y`)
-	var nlist []Node
-	for _, n := range nodes {
-		nlist = append(nlist, n)
-	}
-
-	sources := Sources(nlist)
-	if len(sources) != 2 {
-		t.Fatalf("bad: %v", sources)
-	}
-
-	var haveA, haveX bool
-	for _, n := range sources {
-		name := n.(*BasicNode).Name
-		switch name {
-		case "a":
-			haveA = true
-		case "x":
-			haveX = true
-		}
-	}
-	if !haveA || !haveX {
-		t.Fatalf("missing source %v %v", haveA, haveX)
-	}
-}
-
-func TestUnreachable(t *testing.T) {
-	nodes := ParseBasic(`a -> b
-a -> c
-a -> d
-b -> e
-c -> e
-d -> f
-f -> a
-x -> y
-y -> z`)
-	var nlist []Node
-	for _, n := range nodes {
-		nlist = append(nlist, n)
-	}
-
-	unreached := Unreachable(nodes["a"], nlist)
-	if len(unreached) != 3 {
-		t.Fatalf("bad: %v", unreached)
-	}
-
-	var haveX, haveY, haveZ bool
-	for _, n := range unreached {
-		name := n.(*BasicNode).Name
-		switch name {
-		case "x":
-			haveX = true
-		case "y":
-			haveY = true
-		case "z":
-			haveZ = true
-		}
-	}
-	if !haveX || !haveY || !haveZ {
-		t.Fatalf("missing %v %v %v", haveX, haveY, haveZ)
-	}
-}
-
-func TestUnreachable2(t *testing.T) {
-	nodes := ParseBasic(`a -> b
-a -> c
-a -> d
-b -> e
-c -> e
-d -> f
-f -> a
-x -> y
-y -> z`)
-	var nlist []Node
-	for _, n := range nodes {
-		nlist = append(nlist, n)
-	}
-
-	unreached := Unreachable(nodes["x"], nlist)
-	if len(unreached) != 6 {
-		t.Fatalf("bad: %v", unreached)
-	}
-
-	expected := map[string]struct{}{
-		"a": struct{}{},
-		"b": struct{}{},
-		"c": struct{}{},
-		"d": struct{}{},
-		"e": struct{}{},
-		"f": struct{}{},
-	}
-	out := map[string]struct{}{}
-	for _, n := range unreached {
-		name := n.(*BasicNode).Name
-		out[name] = struct{}{}
-	}
-
-	if !reflect.DeepEqual(out, expected) {
-		t.Fatalf("bad: %v %v", out, expected)
-	}
-}