add test for notification command

cmd/mstdn/cmd_notification.go

@@ -17,11 +17,11 @@ func cmdNotification(c *cli.Context) error {
 	for _, n := range notifications {
 		if n.Status != nil {
 			color.Set(color.FgHiRed)
-			fmt.Print(n.Account.Username)
+			fmt.Fprint(c.App.Writer, n.Account.Username)
 			color.Set(color.Reset)
-			fmt.Println(" " + n.Type)
+			fmt.Fprintln(c.App.Writer, " "+n.Type)
 			s := n.Status
-			fmt.Println(textContent(s.Content))
+			fmt.Fprintln(c.App.Writer, textContent(s.Content))
 		}
 	}
 	return nil

cmd/mstdn/cmd_notification_test.go

@@ -0,0 +1,29 @@
+package main
+
+import (
+	"fmt"
+	"net/http"
+	"strings"
+	"testing"
+
+	"github.com/urfave/cli"
+)
+
+func TestCmdNotification(t *testing.T) {
+	out := testWithServer(
+		func(w http.ResponseWriter, r *http.Request) {
+			if r.URL.Path != "/api/v1/notifications" {
+				http.Error(w, http.StatusText(http.StatusNotFound), http.StatusNotFound)
+				return
+			}
+			fmt.Fprintln(w, `[{"type": "rebloged", "status": {"content": "foo"}}]`)
+			return
+		},
+		func(app *cli.App) {
+			app.Run([]string{"mstdn", "notification"})
+		},
+	)
+	if !strings.Contains(out, "rebloged") {
+		t.Fatalf("%q should be contained in output of instance command: %v", "rebloged", out)
+	}
+}