add a test for the clearScreen function

select.go

@@ -380,9 +380,7 @@ func (s *Select) innerRun(cursorPos, scroll int, top rune) (int, string, error)
 	item := items[idx]
 
 	if s.HideSelected {
-		sb.Reset()
-		sb.Clear()
-		sb.Flush()
+		clearScreen(sb)
 	} else {
 		sb.Reset()
 		sb.Write(render(s.Templates.selected, item))
@@ -622,3 +620,9 @@ func render(tpl *template.Template, data interface{}) []byte {
 	}
 	return buf.Bytes()
 }
+
+func clearScreen(sb *screenbuf.ScreenBuf) {
+	sb.Reset()
+	sb.Clear()
+	sb.Flush()
+}

select_test.go

@@ -1,7 +1,10 @@
 package promptui
 
 import (
+	"bytes"
 	"testing"
+
+	"github.com/manifoldco/promptui/screenbuf"
 )
 
 func TestSelectTemplateRender(t *testing.T) {
@@ -148,3 +151,18 @@ Description: {{.Description}}`,
 		}
 	})
 }
+
+func TestClearScreen(t *testing.T) {
+	var buf bytes.Buffer
+	sb := screenbuf.New(&buf)
+
+	sb.WriteString("test")
+	clearScreen(sb)
+
+	got := buf.String()
+	except := "\x1b[1A\x1b[2K\r"
+
+	if except != got {
+		t.Errorf("expected %q, got %q", except, got)
+	}
+}