beam: Router can route beam messages with a convenient set of rules and handlers

Docker-DCO-1.1-Signed-off-by: Solomon Hykes <solomon@docker.com> (github: shykes)

beam/router_test.go

@@ -0,0 +1,96 @@
+package beam
+
+import (
+	"fmt"
+	"io/ioutil"
+	"testing"
+	"os"
+	"sync"
+)
+
+type msg struct {
+	payload []byte
+	attachment *os.File
+}
+
+func (m msg) String() string {
+	return MsgDesc(m.payload, m.attachment)
+}
+
+
+type mockReceiver []msg
+
+func (r *mockReceiver) Send(p []byte, a *os.File) error {
+	(*r) = append((*r), msg{p, a})
+	return nil
+}
+
+func TestSendNoSinkNoRoute(t *testing.T) {
+	r := NewRouter(nil)
+	if err := r.Send([]byte("hello"), nil); err == nil {
+		t.Fatalf("error expected")
+	}
+	a, b, err := os.Pipe()
+	if err != nil {
+		t.Fatal(err)
+	}
+	defer a.Close()
+	defer b.Close()
+	if err := r.Send([]byte("foo bar baz"), a); err == nil {
+		t.Fatalf("error expected")
+	}
+}
+
+func TestSendSinkNoRoute(t *testing.T) {
+	var sink mockReceiver
+	r := NewRouter(&sink)
+	if err := r.Send([]byte("hello"), nil); err != nil {
+		t.Fatal(err)
+	}
+	a, b, err := os.Pipe()
+	if err != nil {
+		t.Fatal(err)
+	}
+	defer a.Close()
+	defer b.Close()
+	if err := r.Send([]byte("world"), a); err != nil {
+		t.Fatal(err)
+	}
+	if len(sink) != 2 {
+		t.Fatalf("%#v\n", sink)
+	}
+	if string(sink[0].payload) != "hello" {
+		t.Fatalf("%#v\n", sink)
+	}
+	if sink[0].attachment != nil {
+		t.Fatalf("%#v\n", sink)
+	}
+	if string(sink[1].payload) != "world" {
+		t.Fatalf("%#v\n", sink)
+	}
+	if sink[1].attachment == nil || sink[1].attachment.Fd() > 42 || sink[1].attachment.Fd() < 0 {
+		t.Fatalf("%v\n", sink)
+	}
+	var tasks sync.WaitGroup
+	tasks.Add(2)
+	go func() {
+		defer tasks.Done()
+		fmt.Printf("[%d] Reading from '%d'\n", os.Getpid(), sink[1].attachment.Fd())
+		data, err := ioutil.ReadAll(sink[1].attachment)
+		if err != nil {
+			t.Fatal(err)
+		}
+		if string(data) != "foo bar\n" {
+			t.Fatalf("%v\n", string(data))
+		}
+	}()
+	go func() {
+		defer tasks.Done()
+		fmt.Printf("[%d] writing to '%d'\n", os.Getpid(), a.Fd())
+		if _, err := fmt.Fprintf(b, "foo bar\n"); err != nil {
+			t.Fatal(err)
+		}
+		b.Close()
+	}()
+	tasks.Wait()
+}