Use an interface for peco.Hub()

This allows us to plug a dummy hub.Hub instance, and avoid nasty
code for testing

interface.go

@@ -63,7 +63,7 @@ type Peco struct {
 	Stdin  io.Reader
 	Stdout io.Writer
 	Stderr io.Writer
-	hub    *hub.Hub
+	hub    MessageHub
 
 	args       []string
 	bufferSize int
@@ -534,3 +534,20 @@ type ExternalCmdFilter struct {
 	query           string
 	thresholdBufsiz int
 }
+
+// MessageHub is the interface that must be satisfied by the
+// message hub component. Unless we're in testing, github.com/peco/peco/hub.Hub
+// is used.
+type MessageHub interface {
+	Batch(func(), bool)
+	DrawCh() chan hub.Payload
+	PagingCh() chan hub.Payload
+	QueryCh() chan hub.Payload
+	SendDraw(interface{})
+	SendDrawPrompt()
+	SendPaging(interface{})
+	SendQuery(string)
+	SendStatusMsg(string)
+	SendStatusMsgAndClear(string, time.Duration)
+	StatusMsgCh() chan hub.Payload
+}

peco.go

@@ -209,7 +209,7 @@ func (p *Peco) Caret() *Caret {
 	return &p.caret
 }
 
-func (p *Peco) Hub() *hub.Hub {
+func (p *Peco) Hub() MessageHub {
 	return p.hub
 }
 

peco_test.go

@@ -11,11 +11,26 @@ import (
 	"time"
 
 	"github.com/nsf/termbox-go"
+	"github.com/peco/peco/hub"
 	"github.com/peco/peco/internal/util"
 	"github.com/stretchr/testify/assert"
 	"golang.org/x/net/context"
 )
 
+type nullHub struct{}
+
+func (h nullHub) Batch(_ func(), _ bool)                          {}
+func (h nullHub) DrawCh() chan hub.Payload                        { return nil }
+func (h nullHub) PagingCh() chan hub.Payload                      { return nil }
+func (h nullHub) QueryCh() chan hub.Payload                       { return nil }
+func (h nullHub) SendDraw(_ interface{})                          {}
+func (h nullHub) SendDrawPrompt()                                 {}
+func (h nullHub) SendPaging(_ interface{})                        {}
+func (h nullHub) SendQuery(_ string)                              {}
+func (h nullHub) SendStatusMsg(_ string)                          {}
+func (h nullHub) SendStatusMsgAndClear(_ string, _ time.Duration) {}
+func (h nullHub) StatusMsgCh() chan hub.Payload                   { return nil }
+
 type interceptorArgs []interface{}
 type interceptor struct {
 	m      sync.Mutex

source.go

@@ -41,12 +41,7 @@ func (s *Source) Setup(ctx context.Context, state *Peco) {
 		defer close(s.setupDone)
 
 		draw := func(state *Peco) {
-			// Not a great thing to do, allowing nil to be passed
-			// as state, but for testing I couldn't come up with anything
-			// better for the moment
-			if state != nil {
-				state.Hub().SendDraw(nil)
-			}
+			state.Hub().SendDraw(nil)
 		}
 
 		go func() {

source_test.go

@@ -44,7 +44,7 @@ func TestSource(t *testing.T) {
 
 	r := addReadDelay(strings.NewReader(strings.Join(lines, "\n")), 2*time.Second)
 	s := NewSource(r, ig, 0, false)
-	go s.Setup(ctx, nil)
+	go s.Setup(ctx, &Peco{hub: nullHub{}})
 
 	timeout := time.After(5 * time.Second)
 	waitout := time.After(1 * time.Second)