Merge pull request #12121 from hashicorp/jbardin/dag-tests

Fix some intermittent dag test failures

dag/walk_test.go

@@ -92,19 +92,31 @@ func TestWalker_error(t *testing.T) {
 }
 
 func TestWalker_newVertex(t *testing.T) {
-	// Run it a bunch of times since it is timing dependent
-	for i := 0; i < 50; i++ {
 	var g AcyclicGraph
 	g.Add(1)
 	g.Add(2)
 	g.Connect(BasicEdge(1, 2))
 
+	// Record function
 	var order []interface{}
-		w := &Walker{Callback: walkCbRecord(&order)}
+	recordF := walkCbRecord(&order)
+	done2 := make(chan int)
+
+	// Build a callback that notifies us when 2 has been walked
+	var w *Walker
+	cb := func(v Vertex) error {
+		if v == 2 {
+			defer close(done2)
+		}
+		return recordF(v)
+	}
+
+	// Add the initial vertices
+	w = &Walker{Callback: cb}
 	w.Update(&g)
 
-		// Wait a bit
+	// if 2 has been visited, the walk is complete so far
-		time.Sleep(10 * time.Millisecond)
+	<-done2
 
 	// Update the graph
 	g.Add(3)
@@ -125,11 +137,8 @@ func TestWalker_newVertex(t *testing.T) {
 		t.Fatalf("bad: %#v", order)
 	}
 }
-}
 
 func TestWalker_removeVertex(t *testing.T) {
-	// Run it a bunch of times since it is timing dependent
-	for i := 0; i < 50; i++ {
 	var g AcyclicGraph
 	g.Add(1)
 	g.Add(2)
@@ -139,7 +148,6 @@ func TestWalker_removeVertex(t *testing.T) {
 	var order []interface{}
 	recordF := walkCbRecord(&order)
 
-		// Build a callback that delays until we close a channel
 	var w *Walker
 	cb := func(v Vertex) error {
 		if v == 1 {
@@ -165,11 +173,8 @@ func TestWalker_removeVertex(t *testing.T) {
 		t.Fatalf("bad: %#v", order)
 	}
 }
-}
 
 func TestWalker_newEdge(t *testing.T) {
-	// Run it a bunch of times since it is timing dependent
-	for i := 0; i < 50; i++ {
 	var g AcyclicGraph
 	g.Add(1)
 	g.Add(2)
@@ -179,16 +184,18 @@ func TestWalker_newEdge(t *testing.T) {
 	var order []interface{}
 	recordF := walkCbRecord(&order)
 
-		// Build a callback that delays until we close a channel
 	var w *Walker
 	cb := func(v Vertex) error {
+		// record where we are first, otherwise the Updated vertex may get
+		// walked before the first visit.
+		err := recordF(v)
+
 		if v == 1 {
 			g.Add(3)
 			g.Connect(BasicEdge(3, 2))
 			w.Update(&g)
 		}
-
+		return err
-			return recordF(v)
 	}
 
 	// Add the initial vertices
@@ -206,16 +213,14 @@ func TestWalker_newEdge(t *testing.T) {
 		t.Fatalf("bad: %#v", order)
 	}
 }
-}
 
 func TestWalker_removeEdge(t *testing.T) {
-	// Run it a bunch of times since it is timing dependent
-	for i := 0; i < 50; i++ {
 	var g AcyclicGraph
 	g.Add(1)
 	g.Add(2)
 	g.Add(3)
 	g.Connect(BasicEdge(1, 2))
+	g.Connect(BasicEdge(1, 3))
 	g.Connect(BasicEdge(3, 2))
 
 	// Record function
@@ -232,16 +237,18 @@ func TestWalker_removeEdge(t *testing.T) {
 	var w *Walker
 	gateCh := make(chan struct{})
 	cb := func(v Vertex) error {
-			if v == 1 {
+		switch v {
+		case 1:
 			g.RemoveEdge(BasicEdge(3, 2))
 			w.Update(&g)
-			}
 
-			if v == 2 {
+		case 2:
-				close(gateCh)
+			// this visit isn't completed until we've recorded it
-			}
+			// Once the visit is official, we can then close the gate to
+			// let 3 continue.
+			defer close(gateCh)
 
-			if v == 3 {
+		case 3:
 			select {
 			case <-gateCh:
 			case <-time.After(50 * time.Millisecond):
@@ -267,7 +274,6 @@ func TestWalker_removeEdge(t *testing.T) {
 		t.Fatalf("bad: %#v", order)
 	}
 }
-}
 
 // walkCbRecord is a test helper callback that just records the order called.
 func walkCbRecord(order *[]interface{}) WalkFunc {