fix: mascot animation, makes syntax highlighting blink

terminal_cursor_test.go

@@ -25,7 +25,7 @@ func TestTerminalCursorOutputPositionsHardwareBarAfterFrame(t *testing.T) {
 		t.Fatal(err)
 	}
 	wantSuffix := ansi.SetCursorStyle(5) + ansi.CursorPosition(7, 4) + ansi.ShowCursor
-	if !strings.HasSuffix(string(content), wantSuffix) {
+	if !strings.HasSuffix(string(content), wantSuffix+ansi.ResetSynchronizedOutputMode) {
 		t.Fatalf("cursor output = %q, want suffix %q", content, wantSuffix)
 	}
 }
@@ -46,7 +46,33 @@ func TestTerminalCursorOutputHidesCursorOutsideInsertMode(t *testing.T) {
 	if err != nil {
 		t.Fatal(err)
 	}
-	if !strings.HasSuffix(string(content), ansi.HideCursor) {
+	if !strings.HasSuffix(
+		string(content),
+		ansi.HideCursor+ansi.ResetSynchronizedOutputMode,
+	) {
 		t.Fatalf("cursor output did not hide cursor: %q", content)
 	}
 }
+
+func TestTerminalCursorOutputSynchronizesCompletedFrames(t *testing.T) {
+	file, err := os.CreateTemp(t.TempDir(), "cursor-output")
+	if err != nil {
+		t.Fatal(err)
+	}
+	defer file.Close()
+
+	output := newTerminalCursorOutput(file)
+	output.SetCursor(false, 0, 0)
+	if _, err := output.Write([]byte("animated frame")); err != nil {
+		t.Fatal(err)
+	}
+	content, err := os.ReadFile(file.Name())
+	if err != nil {
+		t.Fatal(err)
+	}
+	want := ansi.SetSynchronizedOutputMode + "animated frame" +
+		ansi.HideCursor + ansi.ResetSynchronizedOutputMode
+	if string(content) != want {
+		t.Fatalf("synchronized frame output = %q, want %q", content, want)
+	}
+}