checkpoint: 0.3.0 ui header, history persistence and history filter

src/app/cli.py

@@ -2,6 +2,7 @@ from __future__ import annotations
 
 from pathlib import Path
 
+from app.history import SessionHistory
 from app.navigator import Navigator
 from app.ui import TerminalUI
 
@@ -10,6 +11,6 @@ def run_cli(start_path: Path | None = None, ui: TerminalUI | None = None) -> Pat
     """Run the interactive directory browser and return the selected path."""
 
     initial_path = (start_path or Path.cwd()).expanduser().resolve()
-    navigator = Navigator(initial_path)
+    navigator = Navigator(initial_path, history=SessionHistory.persistent())
     terminal_ui = ui or TerminalUI()
     return terminal_ui.run(navigator)

src/app/history.py

@@ -1,15 +1,46 @@
 from __future__ import annotations
 
+import os
 from dataclasses import dataclass, field
 from pathlib import Path
 
 
+def default_history_path() -> Path:
+    """Return the default on-disk history location."""
+
+    override = os.environ.get("CD_BROWSER_HISTORY_FILE")
+    if override:
+        return Path(override).expanduser()
+
+    if os.name == "nt":
+        base = Path(os.environ.get("APPDATA", str(Path.home() / "AppData" / "Roaming")))
+    else:
+        base = Path(os.environ.get("XDG_STATE_HOME", str(Path.home() / ".local/state")))
+
+    return base / "cd-browser" / "history.txt"
+
+
 @dataclass(slots=True)
 class SessionHistory:
     """In-memory session history for visited directories."""
 
     _entries: list[Path] = field(default_factory=list)
     _index: int = -1
+    storage_path: Path | None = None
+    max_entries: int = 500
+
+    @classmethod
+    def persistent(
+        cls, storage_path: Path | None = None, max_entries: int = 500
+    ) -> SessionHistory:
+        """Create a history instance backed by an on-disk file."""
+
+        history = cls(
+            storage_path=storage_path or default_history_path(),
+            max_entries=max_entries,
+        )
+        history._load()
+        return history
 
     def visit(self, path: Path) -> Path:
         """Record a directory visit and discard forward history when needed."""
@@ -23,7 +54,9 @@ class SessionHistory:
             self._entries = self._entries[: self._index + 1]
 
         self._entries.append(resolved_path)
+        self._trim_to_limit()
         self._index = len(self._entries) - 1
+        self._persist()
         return resolved_path
 
     @property
@@ -66,3 +99,48 @@ class SessionHistory:
         """Return the full history as an immutable sequence."""
 
         return tuple(self._entries)
+
+    def _load(self) -> None:
+        if self.storage_path is None:
+            return
+
+        try:
+            lines = self.storage_path.read_text(encoding="utf-8").splitlines()
+        except FileNotFoundError:
+            return
+        except OSError:
+            return
+
+        loaded_entries: list[Path] = []
+        for line in lines:
+            raw = line.strip()
+            if not raw:
+                continue
+
+            resolved = Path(raw).expanduser().resolve()
+            if loaded_entries and loaded_entries[-1] == resolved:
+                continue
+
+            loaded_entries.append(resolved)
+
+        self._entries = loaded_entries
+        self._trim_to_limit()
+        self._index = len(self._entries) - 1
+
+    def _persist(self) -> None:
+        if self.storage_path is None:
+            return
+
+        try:
+            self.storage_path.parent.mkdir(parents=True, exist_ok=True)
+            contents = "".join(f"{entry}\n" for entry in self._entries)
+            self.storage_path.write_text(contents, encoding="utf-8")
+        except OSError:
+            return
+
+    def _trim_to_limit(self) -> None:
+        limit = max(1, self.max_entries)
+        if len(self._entries) <= limit:
+            return
+
+        self._entries = self._entries[-limit:]

src/app/ui.py

@@ -6,6 +6,7 @@ import sys
 from collections.abc import Iterator
 from contextlib import contextmanager
 from dataclasses import dataclass
+from importlib import metadata
 from pathlib import Path
 from typing import TextIO
 
@@ -20,6 +21,18 @@ from app.opener import (
 
 ESCAPE_KEY = 27
 BACKSPACE_KEYS = (curses.KEY_BACKSPACE, 127, 8)
+DEFAULT_APP_VERSION = "0.3.0"
+FILTER_COLOR_PAIR = 1
+NORMAL_COLOR_PAIR = 2
+
+
+def _app_version() -> str:
+    """Return installed package version when available."""
+
+    try:
+        return metadata.version("cd-browser")
+    except metadata.PackageNotFoundError:
+        return DEFAULT_APP_VERSION
 
 
 @dataclass(frozen=True, slots=True)
@@ -88,6 +101,30 @@ def build_history_lines(
     ]
 
 
+def build_status_line(
+    navigator: Navigator, filter_mode: bool, filter_query: str
+) -> str:
+    """Build first header line with version and live session toggles."""
+
+    hidden_status = "on" if navigator.show_hidden else "off"
+    file_status = "on" if navigator.show_files else "off"
+    if filter_mode:
+        filter_segment = f"filter: {filter_query}" if filter_query else "filter:"
+    else:
+        filter_segment = "filter: off"
+    history_count = len(navigator.history.entries())
+    return (
+        f"cd-browser v{_app_version()} | hist: {history_count} | "
+        f"{filter_segment} | hidden: {hidden_status} | files: {file_status}"
+    )
+
+
+def build_path_line(path: Path) -> str:
+    """Build second header line with current path."""
+
+    return f"path: {path}"
+
+
 def clamp_scroll_offset(
     selected_index: int, scroll_offset: int, visible_count: int, total_count: int
 ) -> int:
@@ -116,11 +153,17 @@ class TerminalUI:
         self._history_selected_index = 0
         self._tree_scroll_offset = 0
         self._history_scroll_offset = 0
+        self._history_filter_mode = False
+        self._history_filter_query = ""
+        self._history_filter_selected_index = 0
+        self._history_filter_scroll_offset = 0
         self._filter_mode = False
         self._filter_query = ""
         self._filter_selected_index = 0
         self._filter_scroll_offset = 0
         self._status_message: str | None = None
+        self._normal_attr = curses.A_NORMAL
+        self._filter_label_attr = curses.A_BOLD
 
     def run(self, navigator: Navigator) -> Path:
         """Start the interactive session and return the final directory path."""
@@ -132,6 +175,7 @@ class TerminalUI:
     def _run_session(self, stdscr: curses.window, navigator: Navigator) -> Path:
         curses.curs_set(0)
         stdscr.keypad(True)
+        self._initialize_colors()
         original_path = navigator.current_path
 
         while True:
@@ -160,6 +204,7 @@ class TerminalUI:
                 return tree_result
 
     def _render(self, stdscr: curses.window, navigator: Navigator) -> None:
+        stdscr.attrset(self._normal_attr)
         stdscr.erase()
         height, width = stdscr.getmaxyx()
 
@@ -168,23 +213,21 @@ class TerminalUI:
             stdscr.refresh()
             return
 
-        hidden_status = "on" if navigator.show_hidden else "off"
+        status_line = build_status_line(
-        file_status = "on" if navigator.show_files else "off"
+            navigator, filter_mode=self._filter_mode, filter_query=self._filter_query
-        path_text = (
-            f"{navigator.current_path} [hidden: {hidden_status}] [files: {file_status}]"
         )
-        stdscr.addnstr(0, 0, path_text, max(0, width - 1))
+        path_line = build_path_line(navigator.current_path)
-
+        self._render_status_line(
-        start_row = 2
+            stdscr,
-        if self._filter_mode:
-            stdscr.addnstr(
-                1,
             0,
-                f"Filter: {self._filter_query}",
+            width,
-                max(0, width - 1),
+            status_line,
-                curses.A_BOLD,
+            filter_active=self._filter_mode,
         )
-            start_row = 3
+        stdscr.addnstr(
+            1, 0, path_line, max(0, width - 1), self._normal_attr | curses.A_DIM
+        )
+        start_row = 2
 
         lines, selected_index = self._build_tree_lines_for_render(navigator)
         footer_rows = 1 if self._status_message else 0
@@ -208,7 +251,13 @@ class TerminalUI:
             scroll_offset = self._tree_scroll_offset
 
         if self._filter_mode and self._filter_query and not lines:
-            stdscr.addnstr(start_row, 0, "No matches", max(0, width - 1), curses.A_DIM)
+            stdscr.addnstr(
+                start_row,
+                0,
+                "No matches",
+                max(0, width - 1),
+                self._normal_attr | curses.A_DIM,
+            )
         else:
             for row, line in enumerate(
                 lines[scroll_offset : scroll_offset + visible_count],
@@ -217,7 +266,11 @@ class TerminalUI:
                 if row >= height:
                     break
 
-                attributes = curses.A_REVERSE if line.is_selected else curses.A_NORMAL
+                attributes = (
+                    self._normal_attr | curses.A_REVERSE
+                    if line.is_selected
+                    else self._normal_attr
+                )
                 stdscr.addnstr(row, 0, line.text, max(0, width - 1), attributes)
 
         if self._status_message and height > 0:
@@ -226,7 +279,7 @@ class TerminalUI:
                 0,
                 self._status_message,
                 max(0, width - 1),
-                curses.A_DIM,
+                self._normal_attr | curses.A_DIM,
             )
 
         stdscr.refresh()
@@ -258,42 +311,91 @@ class TerminalUI:
     def _render_history_mode(
         self, stdscr: curses.window, navigator: Navigator, width: int, height: int
     ) -> None:
-        history_lines = build_history_lines(
+        stdscr.attrset(self._normal_attr)
-            navigator.history.entries(), self._history_selected_index
+        status_line = build_status_line(
+            navigator,
+            filter_mode=self._history_filter_mode,
+            filter_query=self._history_filter_query,
         )
-        start_row = 1
+        path_line = build_path_line(navigator.current_path)
+        self._render_status_line(
+            stdscr,
+            0,
+            width,
+            status_line,
+            filter_active=self._history_filter_mode,
+        )
+        stdscr.addnstr(
+            1, 0, path_line, max(0, width - 1), self._normal_attr | curses.A_DIM
+        )
+
+        history_entries = navigator.history.entries()
+        history_lines, selected_index = self._build_history_lines_for_render(
+            history_entries
+        )
+        start_row = 2
         footer_rows = 1 if self._status_message else 0
         visible_count = max(0, height - start_row - 1 - footer_rows)
+        if self._history_filter_mode:
+            self._history_filter_scroll_offset = clamp_scroll_offset(
+                selected_index,
+                self._history_filter_scroll_offset,
+                visible_count,
+                len(history_lines),
+            )
+            scroll_offset = self._history_filter_scroll_offset
+        else:
             self._history_scroll_offset = clamp_scroll_offset(
-            self._history_selected_index,
+                selected_index,
                 self._history_scroll_offset,
                 visible_count,
                 len(history_lines),
             )
+            scroll_offset = self._history_scroll_offset
 
-        stdscr.addnstr(start_row, 0, "History:", max(0, width - 1), curses.A_BOLD)
+        stdscr.addnstr(
+            start_row,
+            0,
+            "History:",
+            max(0, width - 1),
+            self._normal_attr | curses.A_BOLD,
+        )
 
         for index, line in enumerate(
-            history_lines[
+            history_lines[scroll_offset : scroll_offset + visible_count],
-                self._history_scroll_offset : self._history_scroll_offset
-                + visible_count
-            ],
             start=1,
         ):
             row = start_row + index
             if row >= height:
                 break
 
-            attributes = curses.A_REVERSE if line.is_selected else curses.A_NORMAL
+            attributes = (
+                self._normal_attr | curses.A_REVERSE
+                if line.is_selected
+                else self._normal_attr
+            )
             stdscr.addnstr(row, 0, line.text, max(0, width - 1), attributes)
 
+        if (
+            self._history_filter_mode
+            and self._history_filter_query
+            and not history_lines
+        ):
+            stdscr.addnstr(
+                start_row + 1,
+                0,
+                "No matches",
+                max(0, width - 1),
+                self._normal_attr | curses.A_DIM,
+            )
+
         if self._status_message and height > 0:
             stdscr.addnstr(
                 height - 1,
                 0,
                 self._status_message,
                 max(0, width - 1),
-                curses.A_DIM,
+                self._normal_attr | curses.A_DIM,
             )
 
     def _toggle_history_mode(self, navigator: Navigator) -> None:
@@ -302,14 +404,172 @@ class TerminalUI:
         if self._history_mode:
             self._history_selected_index = self._get_current_history_index(navigator)
             self._history_scroll_offset = 0
+            self._history_filter_mode = False
+            self._history_filter_query = ""
+            self._history_filter_selected_index = 0
+            self._history_filter_scroll_offset = 0
+            return
+
+        self._history_filter_mode = False
+        self._history_filter_query = ""
+        self._history_filter_selected_index = 0
+        self._history_filter_scroll_offset = 0
+
+    def _initialize_colors(self) -> None:
+        self._normal_attr = curses.A_NORMAL
+        self._filter_label_attr = curses.A_BOLD
+        if not curses.has_colors():
+            return
+
+        try:
+            curses.start_color()
+            curses.use_default_colors()
+            curses.init_pair(NORMAL_COLOR_PAIR, curses.COLOR_WHITE, -1)
+            curses.init_pair(FILTER_COLOR_PAIR, curses.COLOR_GREEN, -1)
+            self._normal_attr = curses.color_pair(NORMAL_COLOR_PAIR)
+            self._filter_label_attr = (
+                curses.color_pair(FILTER_COLOR_PAIR) | curses.A_BOLD
+            )
+        except curses.error:
+            self._normal_attr = curses.A_NORMAL
+            self._filter_label_attr = curses.A_BOLD
+
+    def _render_status_line(
+        self,
+        stdscr: curses.window,
+        row: int,
+        width: int,
+        status_line: str,
+        filter_active: bool,
+    ) -> None:
+        max_width = max(0, width - 1)
+        if not filter_active:
+            stdscr.attrset(self._normal_attr)
+            stdscr.addnstr(row, 0, status_line, max_width)
+            stdscr.attrset(self._normal_attr)
+            return
+
+        prefix, marker, suffix = status_line.partition("filter:")
+        if not marker:
+            stdscr.attrset(self._normal_attr)
+            stdscr.addnstr(row, 0, status_line, max_width)
+            stdscr.attrset(self._normal_attr)
+            return
+
+        x = 0
+        stdscr.attrset(self._normal_attr)
+        stdscr.addnstr(row, x, prefix, max_width)
+        x += min(len(prefix), max_width)
+        if x >= max_width:
+            return
+
+        marker_width = max_width - x
+        stdscr.attrset(self._filter_label_attr)
+        stdscr.addnstr(row, x, marker, marker_width)
+        x += min(len(marker), marker_width)
+        if x >= max_width:
+            return
+
+        stdscr.attrset(self._normal_attr)
+        stdscr.addnstr(row, x, suffix, max_width - x)
+        stdscr.attrset(self._normal_attr)
 
     def _handle_history_key(
         self, key: int, navigator: Navigator, stdscr: curses.window | None = None
     ) -> None:
         history_entries = navigator.history.entries()
+        matches = self._matching_history_indices(history_entries)
+
+        if self._history_filter_mode:
+            if key == ESCAPE_KEY:
+                self._history_filter_mode = False
+                self._history_filter_query = ""
+                self._history_filter_selected_index = 0
+                self._history_filter_scroll_offset = 0
+                return
+
+            if key in (curses.KEY_ENTER, 10, 13):
+                if not matches:
+                    return
+
+                selected_entry_index = matches[self._history_filter_selected_index]
+                navigator.select_history_entry(selected_entry_index)
+                self._history_mode = False
+                self._history_filter_mode = False
+                self._history_filter_query = ""
+                self._history_filter_selected_index = 0
+                self._history_filter_scroll_offset = 0
+                self._tree_scroll_offset = 0
+                return
+
+            if key == curses.KEY_UP:
+                self._history_filter_selected_index = move_selection(
+                    self._history_filter_selected_index,
+                    step=-1,
+                    entry_count=len(matches),
+                )
+                return
+
+            if key == curses.KEY_DOWN:
+                self._history_filter_selected_index = move_selection(
+                    self._history_filter_selected_index,
+                    step=1,
+                    entry_count=len(matches),
+                )
+                return
+
+            if key == curses.KEY_PPAGE:
+                step = -self._page_step(stdscr, start_row=3)
+                self._history_filter_selected_index = move_selection(
+                    self._history_filter_selected_index,
+                    step=step,
+                    entry_count=len(matches),
+                )
+                return
+
+            if key == curses.KEY_NPAGE:
+                step = self._page_step(stdscr, start_row=3)
+                self._history_filter_selected_index = move_selection(
+                    self._history_filter_selected_index,
+                    step=step,
+                    entry_count=len(matches),
+                )
+                return
+
+            if key == curses.KEY_HOME:
+                self._history_filter_selected_index = 0
+                return
+
+            if key == curses.KEY_END and matches:
+                self._history_filter_selected_index = len(matches) - 1
+                return
+
+            if key in BACKSPACE_KEYS:
+                self._history_filter_query = self._history_filter_query[:-1]
+                self._history_filter_selected_index = 0
+                self._history_filter_scroll_offset = 0
+                return
+
+            if 32 <= key <= 126:
+                self._history_filter_query += chr(key)
+                self._history_filter_selected_index = 0
+                self._history_filter_scroll_offset = 0
+
+            return
 
         if key in (ESCAPE_KEY, ord("h")):
             self._history_mode = False
+            self._history_filter_mode = False
+            self._history_filter_query = ""
+            self._history_filter_selected_index = 0
+            self._history_filter_scroll_offset = 0
+            return
+
+        if key == ord("/"):
+            self._history_filter_mode = True
+            self._history_filter_query = ""
+            self._history_filter_selected_index = 0
+            self._history_filter_scroll_offset = 0
             return
 
         if key == curses.KEY_UP:
@@ -329,7 +589,7 @@ class TerminalUI:
             return
 
         if key == curses.KEY_PPAGE:
-            step = -self._page_step(stdscr, start_row=1)
+            step = -self._page_step(stdscr, start_row=3)
             self._history_selected_index = move_selection(
                 self._history_selected_index,
                 step=step,
@@ -338,7 +598,7 @@ class TerminalUI:
             return
 
         if key == curses.KEY_NPAGE:
-            step = self._page_step(stdscr, start_row=1)
+            step = self._page_step(stdscr, start_row=3)
             self._history_selected_index = move_selection(
                 self._history_selected_index,
                 step=step,
@@ -357,6 +617,10 @@ class TerminalUI:
         if key in (curses.KEY_ENTER, 10, 13) and history_entries:
             navigator.select_history_entry(self._history_selected_index)
             self._history_mode = False
+            self._history_filter_mode = False
+            self._history_filter_query = ""
+            self._history_filter_selected_index = 0
+            self._history_filter_scroll_offset = 0
             self._tree_scroll_offset = 0
 
     def _handle_filter_key(
@@ -576,6 +840,41 @@ class TerminalUI:
             if query in entry.name.casefold()
         ]
 
+    def _matching_history_indices(self, entries: tuple[Path, ...]) -> list[int]:
+        if not self._history_filter_query:
+            return list(range(len(entries)))
+
+        query = self._history_filter_query.casefold()
+        return [
+            index
+            for index, entry in enumerate(entries)
+            if query in str(entry).casefold()
+        ]
+
+    def _build_history_lines_for_render(
+        self, entries: tuple[Path, ...]
+    ) -> tuple[list[HistoryLine], int]:
+        if not self._history_filter_mode:
+            return build_history_lines(entries, self._history_selected_index), (
+                self._history_selected_index
+            )
+
+        matches = self._matching_history_indices(entries)
+        if not matches:
+            self._history_filter_selected_index = 0
+            return [], 0
+
+        self._history_filter_selected_index = max(
+            0, min(self._history_filter_selected_index, len(matches) - 1)
+        )
+        return [
+            HistoryLine(
+                text=str(entries[entry_index]),
+                is_selected=match_index == self._history_filter_selected_index,
+            )
+            for match_index, entry_index in enumerate(matches)
+        ], self._history_filter_selected_index
+
     def _page_step(self, stdscr: curses.window | None, start_row: int) -> int:
         if stdscr is None:
             return 10

tests/test_history.py

@@ -2,7 +2,7 @@ from pathlib import Path
 
 import pytest
 
-from app.history import SessionHistory
+from app.history import SessionHistory, default_history_path
 
 
 def test_visit_records_current_directory(tmp_path: Path) -> None:
@@ -82,3 +82,48 @@ def test_select_raises_for_invalid_index() -> None:
 
     with pytest.raises(IndexError):
         history.select(0)
+
+
+def test_persistent_history_loads_entries_from_disk(tmp_path: Path) -> None:
+    first = tmp_path / "first"
+    second = tmp_path / "second"
+    for directory in (first, second):
+        directory.mkdir()
+    history_file = tmp_path / "history.txt"
+    history_file.write_text(f"{first}\n{second}\n", encoding="utf-8")
+
+    history = SessionHistory.persistent(storage_path=history_file)
+
+    assert history.entries() == (first.resolve(), second.resolve())
+    assert history.current == second.resolve()
+
+
+def test_persistent_history_visit_writes_to_disk_and_applies_limit(
+    tmp_path: Path,
+) -> None:
+    first = tmp_path / "first"
+    second = tmp_path / "second"
+    third = tmp_path / "third"
+    for directory in (first, second, third):
+        directory.mkdir()
+    history_file = tmp_path / "state" / "history.txt"
+
+    history = SessionHistory.persistent(storage_path=history_file, max_entries=2)
+    history.visit(first)
+    history.visit(second)
+    history.visit(third)
+
+    assert history.entries() == (second.resolve(), third.resolve())
+    assert history_file.read_text(encoding="utf-8").splitlines() == [
+        str(second.resolve()),
+        str(third.resolve()),
+    ]
+
+
+def test_default_history_path_uses_override_env(
+    monkeypatch: pytest.MonkeyPatch, tmp_path: Path
+) -> None:
+    override = tmp_path / "custom-history.txt"
+    monkeypatch.setenv("CD_BROWSER_HISTORY_FILE", str(override))
+
+    assert default_history_path() == override

tests/test_ui.py

@@ -5,11 +5,13 @@ import pytest
 
 from app.navigator import Navigator, VisibleEntry
 from app.ui import (
+    ESCAPE_KEY,
     HistoryLine,
     RenderLine,
     TerminalUI,
     build_history_lines,
     build_render_lines,
+    build_status_line,
     clamp_scroll_offset,
     format_entry,
     move_selection,
@@ -147,6 +149,62 @@ def test_history_mode_enter_selects_entry_and_exits(tmp_path: Path) -> None:
     assert navigator.selected_index == 0
 
 
+def test_history_mode_slash_activates_history_filter() -> None:
+    ui = TerminalUI()
+    navigator = Navigator(Path.cwd())
+    ui._history_mode = True
+
+    ui._handle_history_key(ord("/"), navigator)
+
+    assert ui._history_filter_mode is True
+    assert ui._history_filter_query == ""
+
+
+def test_history_filter_enter_selects_filtered_entry_and_exits_history(
+    tmp_path: Path,
+) -> None:
+    root = tmp_path / "root"
+    alpha = root / "alpha"
+    beta = root / "beta"
+    root.mkdir()
+    alpha.mkdir()
+    beta.mkdir()
+
+    navigator = Navigator(root)
+    navigator.set_selected_index(1)
+    navigator.enter_selected_directory()
+    navigator.go_to_parent_directory()
+    navigator.set_selected_index(2)
+    navigator.enter_selected_directory()
+
+    ui = TerminalUI()
+    ui._toggle_history_mode(navigator)
+    ui._history_filter_mode = True
+    ui._history_filter_query = "alpha"
+
+    ui._handle_history_key(10, navigator)
+
+    assert navigator.current_path == alpha.resolve()
+    assert ui._history_mode is False
+    assert ui._history_filter_mode is False
+
+
+def test_history_filter_escape_disables_only_history_filter(tmp_path: Path) -> None:
+    root = tmp_path / "root"
+    root.mkdir()
+    navigator = Navigator(root)
+    ui = TerminalUI()
+    ui._toggle_history_mode(navigator)
+    ui._history_filter_mode = True
+    ui._history_filter_query = "ro"
+
+    ui._handle_history_key(ESCAPE_KEY, navigator)
+
+    assert ui._history_mode is True
+    assert ui._history_filter_mode is False
+    assert ui._history_filter_query == ""
+
+
 def test_history_mode_toggle_off_keeps_current_directory(tmp_path: Path) -> None:
     root = tmp_path / "root"
     root.mkdir()
@@ -264,6 +322,30 @@ def test_filter_matching_is_case_insensitive(tmp_path: Path) -> None:
     assert matches == [1]
 
 
+def test_build_status_line_shows_filter_off_when_filter_mode_is_disabled(
+    tmp_path: Path,
+) -> None:
+    root = tmp_path / "root"
+    root.mkdir()
+    navigator = Navigator(root)
+
+    status_line = build_status_line(navigator, filter_mode=False, filter_query="")
+
+    assert "filter: off" in status_line
+
+
+def test_build_status_line_shows_empty_filter_without_off_when_filter_is_active(
+    tmp_path: Path,
+) -> None:
+    root = tmp_path / "root"
+    root.mkdir()
+    navigator = Navigator(root)
+
+    status_line = build_status_line(navigator, filter_mode=True, filter_query="")
+
+    assert "filter: |" in status_line
+
+
 def test_filter_mode_uses_g_and_g_upper_as_query_characters(tmp_path: Path) -> None:
     root = tmp_path / "root"
     root.mkdir()