fix single line release state

singleline.go

@@ -28,7 +28,16 @@ func singleLineEdit(r rune, s singleLineState) ([]rune, singleLineState) {
 }
 
 func singleLineReleaseState(s singleLineState) []rune {
-	return s.currentWord
+	if len(s.currentWord) == 0 {
+		return nil
+	}
+
+	var ret []rune
+	if s.started {
+		ret = append(ret, ' ')
+	}
+
+	return append(ret, s.currentWord...)
 }
 
 func singleLine() Editor {

singleline_test.go

@@ -16,4 +16,14 @@ func TestSingleLine(t *testing.T) {
 			t.Fatal(b.String())
 		}
 	})
+
+	t.Run("two lines", func(t *testing.T) {
+		var b bytes.Buffer
+		w := textedit.New(&b, textedit.SingleLine())
+		w.Write([]byte("Some sample text...\nwith invalid chars."))
+		w.Flush()
+		if b.String() != "Some sample text... with invalid chars." {
+			t.Fatal(b.String())
+		}
+	})
 }