Hermes-agent

tests/test_model_picker_scroll.py

@@ -0,0 +1,117 @@
+"""Tests for the scrolling viewport logic in _curses_prompt_choice (issue #5755).
+
+The "More providers" submenu has 13 entries (11 extended + custom + cancel).
+Before the fix, _curses_prompt_choice rendered items starting unconditionally
+from index 0 with no scroll offset.  On terminals shorter than ~16 rows, items
+near the bottom were never drawn.  When the cursor wrapped from 0 to the last
+item (Cancel) via UP-arrow, the highlight rendered off-screen, leaving the menu
+looking like only "Cancel" existed.
+
+The fix adds a scroll_offset that tracks the cursor so the highlighted item
+is always within the visible window.  These tests exercise that logic in
+isolation without requiring a real TTY.
+"""
+
+import sys
+import os
+
+sys.path.insert(0, os.path.join(os.path.dirname(__file__), ".."))
+
+
+# ---------------------------------------------------------------------------
+# Pure scroll-offset logic extracted from _curses_menu for unit testing
+# ---------------------------------------------------------------------------
+
+def _compute_scroll_offset(cursor: int, scroll_offset: int, visible: int, n_choices: int) -> int:
+    """Mirror of the scroll adjustment block inside _curses_menu."""
+    if cursor < scroll_offset:
+        scroll_offset = cursor
+    elif cursor >= scroll_offset + visible:
+        scroll_offset = cursor - visible + 1
+    scroll_offset = max(0, min(scroll_offset, max(0, n_choices - visible)))
+    return scroll_offset
+
+
+def _visible_indices(cursor: int, scroll_offset: int, visible: int, n_choices: int):
+    """Return the list indices that would be rendered for the given state."""
+    scroll_offset = _compute_scroll_offset(cursor, scroll_offset, visible, n_choices)
+    return list(range(scroll_offset, min(scroll_offset + visible, n_choices)))
+
+
+# ---------------------------------------------------------------------------
+# Tests: scroll offset calculation
+# ---------------------------------------------------------------------------
+
+class TestScrollOffsetLogic:
+    N = 13  # typical extended-providers list length
+
+    def test_cursor_at_zero_no_scroll(self):
+        """Start position: offset stays 0, first items visible."""
+        assert _compute_scroll_offset(0, 0, 8, self.N) == 0
+
+    def test_cursor_within_window_unchanged(self):
+        """Cursor inside the current window: offset unchanged."""
+        assert _compute_scroll_offset(5, 0, 8, self.N) == 0
+
+    def test_cursor_at_last_item_scrolls_down(self):
+        """Cursor on Cancel (index 12) with 8-row window: offset = 12 - 8 + 1 = 5."""
+        offset = _compute_scroll_offset(12, 0, 8, self.N)
+        assert offset == 5
+        assert 12 in _visible_indices(12, 0, 8, self.N)
+
+    def test_cursor_wraps_to_cancel_via_up(self):
+        """UP from index 0 wraps to last item; last item must be visible."""
+        wrapped_cursor = (0 - 1) % self.N  # == 12
+        indices = _visible_indices(wrapped_cursor, 0, 8, self.N)
+        assert wrapped_cursor in indices
+
+    def test_cursor_above_window_scrolls_up(self):
+        """Cursor above current window: offset tracks cursor."""
+        # window currently shows [5..12], cursor moves to 3
+        offset = _compute_scroll_offset(3, 5, 8, self.N)
+        assert offset == 3
+        assert 3 in _visible_indices(3, 5, 8, self.N)
+
+    def test_visible_window_never_exceeds_list(self):
+        """Offset is clamped so the window never starts past the list end."""
+        offset = _compute_scroll_offset(12, 0, 20, self.N)  # window larger than list
+        assert offset == 0
+
+    def test_single_item_list(self):
+        """Edge case: one choice, cursor 0."""
+        assert _compute_scroll_offset(0, 0, 8, 1) == 0
+
+    def test_list_fits_in_window_no_scroll_needed(self):
+        """If all choices fit in the visible window, offset is always 0."""
+        for cursor in range(self.N):
+            offset = _compute_scroll_offset(cursor, 0, 20, self.N)
+            assert offset == 0, f"cursor={cursor} should not scroll when window > list"
+
+    def test_cursor_always_in_visible_range(self):
+        """Invariant: cursor is always within the rendered window after adjustment."""
+        visible = 5
+        for cursor in range(self.N):
+            indices = _visible_indices(cursor, 0, visible, self.N)
+            assert cursor in indices, f"cursor={cursor} not in visible={indices}"
+
+    def test_full_navigation_down_cursor_always_visible(self):
+        """Simulate pressing DOWN through all items; cursor always in view."""
+        visible = 6
+        scroll_offset = 0
+        cursor = 0
+        for _ in range(self.N + 2):  # wrap around twice
+            scroll_offset = _compute_scroll_offset(cursor, scroll_offset, visible, self.N)
+            rendered = list(range(scroll_offset, min(scroll_offset + visible, self.N)))
+            assert cursor in rendered, f"cursor={cursor} not in rendered={rendered}"
+            cursor = (cursor + 1) % self.N
+
+    def test_full_navigation_up_cursor_always_visible(self):
+        """Simulate pressing UP through all items; cursor always in view."""
+        visible = 6
+        scroll_offset = 0
+        cursor = 0
+        for _ in range(self.N + 2):
+            scroll_offset = _compute_scroll_offset(cursor, scroll_offset, visible, self.N)
+            rendered = list(range(scroll_offset, min(scroll_offset + visible, self.N)))
+            assert cursor in rendered, f"cursor={cursor} not in rendered={rendered}"
+            cursor = (cursor - 1) % self.N