Feature/update check (#1232)

Periodically fetch the latest available version, and the UI will shows a new menu for the download link. It checks both the daemon version and the UI version.

version/update_test.go

@@ -0,0 +1,101 @@
+package version
+
+import (
+	"fmt"
+	"net/http"
+	"net/http/httptest"
+	"sync"
+	"testing"
+	"time"
+)
+
+func TestNewUpdate(t *testing.T) {
+	version = "1.0.0"
+	svr := httptest.NewServer(http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
+		fmt.Fprintf(w, "10.0.0")
+	}))
+	defer svr.Close()
+	versionURL = svr.URL
+
+	wg := &sync.WaitGroup{}
+	wg.Add(1)
+
+	onUpdate := false
+	u := NewUpdate()
+	defer u.StopWatch()
+	u.SetOnUpdateListener(func() {
+		onUpdate = true
+		wg.Done()
+	})
+
+	waitTimeout(wg)
+	if onUpdate != true {
+		t.Errorf("update not found")
+	}
+}
+
+func TestDoNotUpdate(t *testing.T) {
+	version = "11.0.0"
+	svr := httptest.NewServer(http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
+		fmt.Fprintf(w, "10.0.0")
+	}))
+	defer svr.Close()
+	versionURL = svr.URL
+
+	wg := &sync.WaitGroup{}
+	wg.Add(1)
+
+	onUpdate := false
+	u := NewUpdate()
+	defer u.StopWatch()
+	u.SetOnUpdateListener(func() {
+		onUpdate = true
+		wg.Done()
+	})
+
+	waitTimeout(wg)
+	if onUpdate == true {
+		t.Errorf("invalid update")
+	}
+}
+
+func TestDaemonUpdate(t *testing.T) {
+	version = "11.0.0"
+	svr := httptest.NewServer(http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
+		fmt.Fprintf(w, "11.0.0")
+	}))
+	defer svr.Close()
+	versionURL = svr.URL
+
+	wg := &sync.WaitGroup{}
+	wg.Add(1)
+
+	onUpdate := false
+	u := NewUpdate()
+	defer u.StopWatch()
+	u.SetOnUpdateListener(func() {
+		onUpdate = true
+		wg.Done()
+	})
+
+	u.SetDaemonVersion("10.0.0")
+
+	waitTimeout(wg)
+	if onUpdate != true {
+		t.Errorf("invalid dameon version check")
+	}
+}
+
+func waitTimeout(wg *sync.WaitGroup) {
+	c := make(chan struct{})
+	go func() {
+		wg.Wait()
+		close(c)
+	}()
+	select {
+	case <-c:
+		return
+	case <-time.After(time.Second):
+		return
+	}
+}