fix: restore saved machine screens after reconnect (#4126)

refs #3842

1 files changed, 89 insertions, 0 deletions

diff --git a/tests/support/terminal_screen.rs b/tests/support/terminal_screen.rs
new file mode 100644
index 00000000..45d7731b
--- /dev/null
+++ b/tests/support/terminal_screen.rs
@@ -0,0 +1,89 @@
+use std::{mem::size_of, ptr};
+
+// Reuse the generated C API; this test observer needs only terminal parsing and formatting.
+#[allow(
+    dead_code,
+    non_camel_case_types,
+    non_snake_case,
+    non_upper_case_globals
+)]
+#[path = "../../src/ghostty/bindings.rs"]
+mod ffi;
+
+struct Screen {
+    terminal: ffi::GhosttyTerminal,
+    formatter: ffi::GhosttyFormatter,
+}
+
+impl Drop for Screen {
+    fn drop(&mut self) {
+        unsafe {
+            ffi::ghostty_formatter_free(self.formatter);
+            ffi::ghostty_terminal_free(self.terminal);
+        }
+    }
+}
+
+pub fn text(output: &[u8], cols: u16, rows: u16) -> String {
+    let mut screen = Screen {
+        terminal: ptr::null_mut(),
+        formatter: ptr::null_mut(),
+    };
+    let options = ffi::GhosttyFormatterTerminalOptions {
+        size: size_of::<ffi::GhosttyFormatterTerminalOptions>(),
+        emit: ffi::GhosttyFormatterFormat_GHOSTTY_FORMATTER_FORMAT_PLAIN,
+        trim: true,
+        extra: ffi::GhosttyFormatterTerminalExtra {
+            size: size_of::<ffi::GhosttyFormatterTerminalExtra>(),
+            screen: ffi::GhosttyFormatterScreenExtra {
+                size: size_of::<ffi::GhosttyFormatterScreenExtra>(),
+                ..Default::default()
+            },
+            ..Default::default()
+        },
+        ..Default::default()
+    };
+    unsafe {
+        assert_eq!(
+            ffi::ghostty_terminal_new(ptr::null(), &mut screen.terminal, cols, rows),
+            ffi::GhosttyResult_GHOSTTY_SUCCESS
+        );
+        ffi::ghostty_terminal_vt_write(screen.terminal, output.as_ptr(), output.len());
+        assert_eq!(
+            ffi::ghostty_formatter_terminal_new(
+                ptr::null(),
+                &mut screen.formatter,
+                screen.terminal,
+                options,
+            ),
+            ffi::GhosttyResult_GHOSTTY_SUCCESS
+        );
+        let mut len = 0;
+        let result =
+            ffi::ghostty_formatter_format_buf(screen.formatter, ptr::null_mut(), 0, &mut len);
+        assert!(matches!(
+            result,
+            ffi::GhosttyResult_GHOSTTY_SUCCESS | ffi::GhosttyResult_GHOSTTY_OUT_OF_SPACE
+        ));
+        let mut bytes = vec![0; len];
+        assert_eq!(
+            ffi::ghostty_formatter_format_buf(
+                screen.formatter,
+                bytes.as_mut_ptr(),
+                bytes.len(),
+                &mut len
+            ),
+            ffi::GhosttyResult_GHOSTTY_SUCCESS
+        );
+        String::from_utf8_lossy(&bytes[..len]).into_owned()
+    }
+}
+
+#[test]
+fn screen_text_reconstructs_partial_redraws() {
+    let output = b"REMOTE_SURVIVED\x1b[1;8HSTILL_SELECTED";
+    assert!(!output
+        .windows(b"REMOTE_STILL_SELECTED".len())
+        .any(|part| part == b"REMOTE_STILL_SELECTED"));
+    assert!(text(output, 80, 24).contains("REMOTE_STILL_SELECTED"));
+}