add test

Signed-off-by: Vasiliy Tolstov <v.tolstov@unistack.org>

flow/dag_test.go

@@ -7,6 +7,55 @@ import (
 	"github.com/silas/dag"
 )
 
+func TestDeps(t *testing.T) {
+	d := &dag.AcyclicGraph{}
+
+	v0 := d.Add(&node{"v0"})
+	v1 := d.Add(&node{"v1"})
+	v2 := d.Add(&node{"v2"})
+	v3 := d.Add(&node{"v3"})
+	v4 := d.Add(&node{"v4"})
+
+	d.Connect(dag.BasicEdge(v0, v1))
+	d.Connect(dag.BasicEdge(v1, v2))
+	d.Connect(dag.BasicEdge(v2, v4))
+	d.Connect(dag.BasicEdge(v0, v3))
+	d.Connect(dag.BasicEdge(v3, v4))
+
+	if err := d.Validate(); err != nil {
+		t.Fatal(err)
+	}
+
+	d.TransitiveReduction()
+
+	var steps [][]string
+	fn := func(n dag.Vertex, idx int) error {
+		if idx == 0 {
+			steps = make([][]string, 1)
+			steps[0] = make([]string, 0, 1)
+		} else if idx >= len(steps) {
+			tsteps := make([][]string, idx+1)
+			copy(tsteps, steps)
+			steps = tsteps
+			steps[idx] = make([]string, 0, 1)
+		}
+		steps[idx] = append(steps[idx], fmt.Sprintf("%s", n))
+		return nil
+	}
+
+	start := &node{"v0"}
+	err := d.SortedDepthFirstWalk([]dag.Vertex{start}, fn)
+	checkErr(t, err)
+
+	for idx, steps := range steps {
+		fmt.Printf("level %d steps %#+v\n", idx, steps)
+	}
+
+	if len(steps[2]) != 1 {
+		t.Fatalf("invalid steps %#+v", steps[2])
+	}
+}
+
 func checkErr(t *testing.T, err error) {
 	if err != nil {
 		t.Fatal(err)