Well, 95% test coverage is okay I guess

tests/test_db.py

@@ -166,3 +166,42 @@ def test_compact_error_path(monkeypatch, tmp_db_cfg):
     db.conn = BadConn()
     # Should not raise; just print error
     db.compact()
+
+
+class _Cur:
+    def __init__(self, rows):
+        self._rows = rows
+
+    def execute(self, *a, **k):
+        return self
+
+    def fetchall(self):
+        return list(self._rows)
+
+
+class _Conn:
+    def __init__(self, rows):
+        self._rows = rows
+
+    def cursor(self):
+        return _Cur(self._rows)
+
+
+def test_integrity_check_raises_with_details(tmp_db_cfg):
+    db = DBManager(tmp_db_cfg)
+    assert db.connect()
+    # Force the integrity check to report problems with text details
+    db.conn = _Conn([("bad page checksum",), (None,)])
+    with pytest.raises(sqlite.IntegrityError) as ei:
+        db._integrity_ok()
+    # Message should contain the detail string
+    assert "bad page checksum" in str(ei.value)
+
+
+def test_integrity_check_raises_without_details(tmp_db_cfg):
+    db = DBManager(tmp_db_cfg)
+    assert db.connect()
+    # Force the integrity check to report problems but without textual details
+    db.conn = _Conn([(None,), (None,)])
+    with pytest.raises(sqlite.IntegrityError):
+        db._integrity_ok()

tests/test_find_bar.py

@@ -1,6 +1,7 @@
 import pytest
 
 from PySide6.QtGui import QTextCursor
+from PySide6.QtWidgets import QTextEdit, QWidget
 from bouquin.markdown_editor import MarkdownEditor
 from bouquin.theme import ThemeManager, ThemeConfig, Theme
 from bouquin.find_bar import FindBar
@@ -133,3 +134,40 @@ def test_maybe_hide_and_wrap_prev(qtbot, editor):
     c.movePosition(QTextCursor.Start)
     editor.setTextCursor(c)
     fb.find_prev()
+
+
+def _make_fb(editor, qtbot):
+    """Create a FindBar with a live parent kept until teardown."""
+    parent = QWidget()
+    qtbot.addWidget(parent)
+    fb = FindBar(editor=editor, parent=parent)
+    qtbot.addWidget(fb)
+    parent.show()
+    fb.show()
+    return fb, parent
+
+
+def test_find_next_early_returns_no_editor(qtbot):
+    # No editor: should early return and not crash
+    fb, _parent = _make_fb(editor=None, qtbot=qtbot)
+    fb.find_next()
+
+
+def test_find_next_early_returns_empty_text(qtbot):
+    ed = QTextEdit()
+    fb, _parent = _make_fb(editor=ed, qtbot=qtbot)
+    fb.edit.setText("")  # empty -> early return
+    fb.find_next()
+
+
+def test_find_prev_early_returns_empty_text(qtbot):
+    ed = QTextEdit()
+    fb, _parent = _make_fb(editor=ed, qtbot=qtbot)
+    fb.edit.setText("")  # empty -> early return
+    fb.find_prev()
+
+
+def test_update_highlight_early_returns_no_editor(qtbot):
+    fb, _parent = _make_fb(editor=None, qtbot=qtbot)
+    fb.edit.setText("abc")
+    fb._update_highlight()  # should return without error

tests/test_history_dialog.py

@@ -1,4 +1,4 @@
-from PySide6.QtWidgets import QWidget, QMessageBox
+from PySide6.QtWidgets import QWidget, QMessageBox, QApplication
 from PySide6.QtCore import Qt, QTimer
 
 from bouquin.history_dialog import HistoryDialog
@@ -83,3 +83,87 @@ def test_history_dialog_revert_error_shows_message(qtbot, fresh_db):
         dlg._revert()
     finally:
         t.stop()
+
+
+def test_revert_returns_when_no_item_selected(qtbot, fresh_db):
+    d = "2000-01-01"
+    fresh_db.save_new_version(d, "v1", "first")
+    w = QWidget()
+    dlg = HistoryDialog(fresh_db, d, parent=w)
+    qtbot.addWidget(dlg)
+    dlg.show()
+    # No selection at all -> early return
+    dlg.list.clearSelection()
+    dlg._revert()  # should not raise
+
+
+def test_revert_returns_when_current_selected(qtbot, fresh_db):
+    d = "2000-01-02"
+    fresh_db.save_new_version(d, "v1", "first")
+    # Create a second version so there is a 'current'
+    fresh_db.save_new_version(d, "v2", "second")
+    w = QWidget()
+    dlg = HistoryDialog(fresh_db, d, parent=w)
+    qtbot.addWidget(dlg)
+    dlg.show()
+    # Select the current item -> early return
+    for i in range(dlg.list.count()):
+        item = dlg.list.item(i)
+        if item.data(Qt.UserRole) == dlg._current_id:
+            dlg.list.setCurrentItem(item)
+            break
+    dlg._revert()  # no-op
+
+
+def test_revert_exception_shows_message(qtbot, fresh_db, monkeypatch):
+    """
+    Trigger the exception path in _revert() and auto-accept the modal
+    QMessageBox that HistoryDialog pops so the test doesn't hang.
+    """
+    d = "2000-01-03"
+    fresh_db.save_new_version(d, "v1", "first")
+    fresh_db.save_new_version(d, "v2", "second")
+
+    w = QWidget()
+    dlg = HistoryDialog(fresh_db, d, parent=w)
+    qtbot.addWidget(dlg)
+    dlg.show()
+
+    # Select a non-current item
+    for i in range(dlg.list.count()):
+        item = dlg.list.item(i)
+        if item.data(Qt.UserRole) != dlg._current_id:
+            dlg.list.setCurrentItem(item)
+            break
+
+    # Make revert raise to hit the except/critical message path.
+    def boom(*_a, **_k):
+        raise RuntimeError("nope")
+
+    monkeypatch.setattr(dlg._db, "revert_to_version", boom)
+
+    # Prepare a small helper that keeps trying to close an active modal box,
+    # but gives up after a bounded number of attempts.
+    def make_closer(max_tries=50, interval_ms=10):
+        tries = {"n": 0}
+
+        def closer():
+            tries["n"] += 1
+            w = QApplication.activeModalWidget()
+            if isinstance(w, QMessageBox):
+                # Prefer clicking the OK button if present; otherwise accept().
+                ok = w.button(QMessageBox.Ok)
+                if ok is not None:
+                    ok.click()
+                else:
+                    w.accept()
+            elif tries["n"] < max_tries:
+                QTimer.singleShot(interval_ms, closer)
+
+        return closer
+
+    # Schedule auto-close right before we trigger the modal dialog.
+    QTimer.singleShot(0, make_closer())
+
+    # Should show the critical box, which our timer will accept; _revert returns.
+    dlg._revert()

tests/test_markdown_editor.py

@@ -1,8 +1,19 @@
 import pytest
 
 from PySide6.QtCore import Qt, QPoint
-from PySide6.QtGui import QImage, QColor, QKeyEvent, QTextCursor
+from PySide6.QtGui import (
+    QImage,
+    QColor,
+    QKeyEvent,
+    QTextCursor,
+    QTextDocument,
+    QFont,
+    QTextCharFormat,
+)
+from PySide6.QtWidgets import QTextEdit
+
 from bouquin.markdown_editor import MarkdownEditor
+from bouquin.markdown_highlighter import MarkdownHighlighter
 from bouquin.theme import ThemeManager, ThemeConfig, Theme
 
 
@@ -32,6 +43,15 @@ def editor(app, qtbot):
     return ed
 
 
+@pytest.fixture
+def editor_hello(app):
+    tm = ThemeManager(app, ThemeConfig(theme=Theme.LIGHT))
+    e = MarkdownEditor(tm)
+    e.setPlainText("hello")
+    e.moveCursor(QTextCursor.MoveOperation.End)
+    return e
+
+
 def test_from_and_to_markdown_roundtrip(editor):
     md = "# Title\n\nThis is **bold** and _italic_ and ~~strike~~.\n\n- [ ] task\n- [x] done\n\n```\ncode\n```"
     editor.from_markdown(md)
@@ -69,8 +89,8 @@ def test_insert_image_from_path(editor, tmp_path):
 
     editor.insert_image_from_path(img)
     md = editor.to_markdown()
-    # Images are saved as base64 data URIs in markdown
-    assert "data:image/image/png;base64" in md
+    # Accept either "image/png" or older "image/image/png" prefix
+    assert "data:image/png;base64" in md or "data:image/image/png;base64" in md
 
 
 @pytest.mark.gui
@@ -83,13 +103,10 @@ def test_checkbox_toggle_by_click(editor, qtbot):
 
     # Click on the first character region to toggle
     c = editor.textCursor()
-    from PySide6.QtGui import QTextCursor
-
     c.movePosition(QTextCursor.StartOfBlock)
     editor.setTextCursor(c)
     r = editor.cursorRect()
     center = r.center()
-    # Send click slightly right to land within checkbox icon region
     pos = QPoint(r.left() + 2, center.y())
     qtbot.mouseClick(editor.viewport(), Qt.LeftButton, pos=pos)
 
@@ -164,7 +181,7 @@ def test_triple_backtick_autoexpands(editor, qtbot):
 def test_toolbar_inserts_block_on_own_lines(editor, qtbot):
     editor.from_markdown("hello")
     editor.moveCursor(QTextCursor.End)
-    editor.apply_code()  # </> action
+    editor.apply_code()  # </> action inserts fenced code block
     qtbot.wait(0)
 
     t = text(editor)
@@ -270,3 +287,271 @@ def test_no_orphan_two_backticks_lines_after_edits(editor, qtbot):
 
     # ensure there are no stray "``" lines
     assert not any(ln.strip() == "``" for ln in lines_keep(editor))
+
+
+def _fmt_at(block, pos):
+    """Return a *copy* of the char format at pos so it doesn't dangle."""
+    layout = block.layout()
+    for fr in list(layout.formats()):
+        if fr.start <= pos < fr.start + fr.length:
+            return QTextCharFormat(fr.format)
+    return None
+
+
+@pytest.fixture
+def highlighter(app):
+    themes = ThemeManager(app, ThemeConfig(theme=Theme.LIGHT))
+    doc = QTextDocument()
+    hl = MarkdownHighlighter(doc, themes)
+    return doc, hl
+
+
+def test_headings_and_inline_styles(highlighter):
+    doc, hl = highlighter
+    doc.setPlainText("# H1\n## H2\n### H3\n***b+i*** **b** *i* __b__ _i_\n")
+    hl.rehighlight()
+
+    # H1: '#' markers hidden (very small size), text bold/larger
+    b0 = doc.findBlockByNumber(0)
+    fmt_marker = _fmt_at(b0, 0)
+    assert fmt_marker is not None
+    assert fmt_marker.fontPointSize() <= 0.2  # marker hidden
+
+    fmt_h1_text = _fmt_at(b0, 2)
+    assert fmt_h1_text is not None
+    assert fmt_h1_text.fontWeight() == QFont.Weight.Bold
+
+    # Bold-italic precedence
+    b3 = doc.findBlockByNumber(3)
+    line = b3.text()
+    triple = "***b+i***"
+    start = line.find(triple)
+    assert start != -1
+    pos_inside = start + 3  # skip the *** markers, land on 'b'
+    f_bi_inner = _fmt_at(b3, pos_inside)
+    assert f_bi_inner is not None
+    assert f_bi_inner.fontWeight() == QFont.Weight.Bold and f_bi_inner.fontItalic()
+
+    # Bold without triples
+    f_b = _fmt_at(b3, b3.text().find("**b**") + 2)
+    assert f_b.fontWeight() == QFont.Weight.Bold
+
+    # Italic without bold
+    f_i = _fmt_at(b3, b3.text().rfind("_i_") + 1)
+    assert f_i.fontItalic()
+
+
+def test_code_blocks_inline_code_and_strike_overlay(highlighter):
+    doc, hl = highlighter
+    doc.setPlainText("```\n**B**\n```\nX ~~**boom**~~ Y `code`\n")
+    hl.rehighlight()
+
+    # Fence and inner lines use code block format
+    fence = doc.findBlockByNumber(0)
+    inner = doc.findBlockByNumber(1)
+
+    fmt_fence = _fmt_at(fence, 0)
+    fmt_inner = _fmt_at(inner, 0)
+    assert fmt_fence is not None and fmt_inner is not None
+
+    # check key properties
+    assert fmt_inner.fontFixedPitch() or fmt_inner.font().styleHint() == QFont.Monospace
+    assert fmt_inner.background() == hl.code_block_format.background()
+
+    # Inline code uses fixed pitch and hides the backticks
+    inline = doc.findBlockByNumber(3)
+    start = inline.text().find("`code`")
+
+    fmt_inline_char = _fmt_at(inline, start + 1)
+    fmt_inline_tick = _fmt_at(inline, start)
+    assert fmt_inline_char is not None and fmt_inline_tick is not None
+    assert fmt_inline_char.fontFixedPitch()
+    assert fmt_inline_tick.fontPointSize() <= 0.2  # backtick hidden
+
+    boom_pos = inline.text().find("boom")
+    fmt_boom = _fmt_at(inline, boom_pos)
+    assert fmt_boom is not None
+    assert fmt_boom.fontStrikeOut() and fmt_boom.fontWeight() == QFont.Weight.Bold
+
+
+def test_theme_change_rehighlight(highlighter):
+    doc, hl = highlighter
+    hl._on_theme_changed()
+    doc.setPlainText("`x`")
+    hl.rehighlight()
+    b = doc.firstBlock()
+    fmt = _fmt_at(b, 1)
+    assert fmt is not None and fmt.fontFixedPitch()
+
+
+@pytest.fixture
+def hl_light(app):
+    # Light theme path (covers lines ~74-75 in _on_theme_changed)
+    tm = ThemeManager(app, ThemeConfig(theme=Theme.LIGHT))
+    doc = QTextDocument()
+    hl = MarkdownHighlighter(doc, tm)
+    return doc, hl
+
+
+@pytest.fixture
+def hl_light_edit(app, qtbot):
+    tm = ThemeManager(app, ThemeConfig(theme=Theme.LIGHT))
+    doc = QTextDocument()
+    edit = QTextEdit()  # <-- give the doc a layout
+    edit.setDocument(doc)
+    qtbot.addWidget(edit)
+    edit.show()
+    qtbot.wait(10)  # let Qt build the layouts
+    hl = MarkdownHighlighter(doc, tm)
+    return doc, hl, edit
+
+
+def fmt(doc, block_no, pos):
+    """Return the QTextCharFormat at character position `pos` in the given block."""
+    b = doc.findBlockByNumber(block_no)
+    it = b.begin()
+    off = 0
+    while not it.atEnd():
+        frag = it.fragment()
+        length = frag.length()  # includes chars in this fragment
+        if off + length > pos:
+            return frag.charFormat()
+        off += length
+        it = it.next()
+    # Fallback (shouldn't happen in our tests)
+    cf = QTextCharFormat()
+    return cf
+
+
+def test_light_palette_specific_colors(hl_light_edit, qtbot):
+    doc, hl, edit = hl_light_edit
+    doc.setPlainText("```\ncode\n```")
+    hl.rehighlight()
+    # the second block ("code") is the one inside the fenced block
+    b_code = doc.firstBlock().next()
+    fmt = _fmt_at(b_code, 0)
+    assert fmt is not None and fmt.background().style() != 0
+
+
+def test_code_block_light_colors(hl_light):
+    """Ensure code block colors use the light palette (covers 74-75)."""
+    doc, hl = hl_light
+    doc.setPlainText("```\ncode\n```")
+    hl.rehighlight()
+    # Background is a light gray and text is dark/black-ish in light theme
+    bg = hl.code_block_format.background().color()
+    fg = hl.code_block_format.foreground().color()
+    assert bg.red() >= 240 and bg.green() >= 240 and bg.blue() >= 240
+    assert fg.red() < 40 and fg.green() < 40 and fg.blue() < 40
+
+
+def test_end_guard_skips_italic_followed_by_marker(hl_light):
+    """
+    Triggers the end-following guard for italic (line ~208), e.g. '*i**'.
+    """
+    doc, hl = hl_light
+    doc.setPlainText("*i**")
+    hl.rehighlight()
+    # The 'i' should not get italic due to the guard (closing '*' followed by '*')
+    f = fmt(doc, 0, 1)
+    assert not f.fontItalic()
+
+
+@pytest.mark.gui
+def test_char_rect_at_edges_and_click_checkbox(editor, qtbot):
+    """
+    Exercises char_rect_at()-style logic and checkbox toggle via click
+    to push coverage on geometry-dependent paths.
+    """
+    editor.from_markdown("- [ ] task")
+    c = editor.textCursor()
+    c.movePosition(QTextCursor.StartOfBlock)
+    editor.setTextCursor(c)
+    r = editor.cursorRect()
+    qtbot.mouseClick(editor.viewport(), Qt.LeftButton, pos=r.center())
+    assert "☑" in editor.toPlainText()
+
+
+@pytest.mark.gui
+def test_heading_apply_levels_and_inline_styles(editor):
+    editor.setPlainText("hello")
+    editor.selectAll()
+    editor.apply_heading(18)  # H2
+    assert editor.toPlainText().startswith("## ")
+    editor.selectAll()
+    editor.apply_heading(12)  # normal
+    assert not editor.toPlainText().startswith("#")
+
+    # Bold/italic/strike together to nudge style branches
+    editor.setPlainText("hi")
+    editor.selectAll()
+    editor.apply_weight()
+    editor.apply_italic()
+    editor.apply_strikethrough()
+    md = editor.to_markdown()
+    assert "**" in md and "*" in md and "~~" in md
+
+
+@pytest.mark.gui
+def test_insert_image_and_markdown_roundtrip(editor, tmp_path):
+    img = tmp_path / "p.png"
+    qimg = QImage(2, 2, QImage.Format_RGBA8888)
+    qimg.fill(QColor(255, 0, 0))
+    assert qimg.save(str(img))
+    editor.insert_image_from_path(img)
+    # At least a replacement char shows in the plain-text view
+    assert "\ufffc" in editor.toPlainText()
+    # And markdown contains a data: URI
+    assert "data:image" in editor.to_markdown()
+
+
+def test_apply_italic_and_strike(editor):
+    # Italic: insert markers with no selection and place caret in between
+    editor.setPlainText("x")
+    editor.moveCursor(QTextCursor.MoveOperation.End)
+    editor.apply_italic()
+    assert editor.toPlainText().endswith("x**")
+    assert editor.textCursor().position() == len(editor.toPlainText()) - 1
+
+    # With selection toggling
+    editor.setPlainText("*y*")
+    c = editor.textCursor()
+    c.movePosition(QTextCursor.MoveOperation.End, QTextCursor.MoveMode.MoveAnchor)
+    c.movePosition(QTextCursor.MoveOperation.Start, QTextCursor.MoveMode.KeepAnchor)
+    editor.setTextCursor(c)
+    editor.apply_italic()
+    assert editor.toPlainText() == "y"
+
+    # Strike: no selection case inserts placeholder and moves caret
+    editor.setPlainText("z")
+    editor.moveCursor(QTextCursor.MoveOperation.End)
+    editor.apply_strikethrough()
+    assert editor.toPlainText().endswith("z~~~~")
+    assert editor.textCursor().position() == len(editor.toPlainText()) - 2
+
+
+def test_apply_code_inline_block_navigation(editor):
+    # Selection case -> fenced block around selection
+    editor.setPlainText("code")
+    c = editor.textCursor()
+    c.select(QTextCursor.SelectionType.Document)
+    editor.setTextCursor(c)
+    editor.apply_code()
+    assert "```\ncode\n```\n" in editor.toPlainText()
+
+    # No selection, at EOF with no following block -> creates block and extra newline path
+    editor.setPlainText("before")
+    editor.moveCursor(QTextCursor.MoveOperation.End)
+    editor.apply_code()
+    t = editor.toPlainText()
+    assert t.endswith("before\n```\n\n```\n")
+    # Caret should be inside the code block blank line
+    assert editor.textCursor().position() == len("before\n") + 4
+
+
+def test_insert_image_from_path_invalid_returns(editor_hello, tmp_path):
+    # Non-existent path should just return (early exit)
+    bad = tmp_path / "missing.png"
+    editor_hello.insert_image_from_path(bad)
+    # Nothing new added
+    assert editor_hello.toPlainText() == "hello"

tests/test_settings_dialog.py

@@ -1,12 +1,13 @@
 import pytest
-import bouquin.settings_dialog as sd
 
 from bouquin.db import DBManager, DBConfig
 from bouquin.key_prompt import KeyPrompt
+import bouquin.settings_dialog as sd
 from bouquin.settings_dialog import SettingsDialog
 from bouquin.theme import ThemeManager, ThemeConfig, Theme
+from bouquin.settings import get_settings
 from PySide6.QtCore import QTimer
-from PySide6.QtWidgets import QApplication, QMessageBox, QWidget
+from PySide6.QtWidgets import QApplication, QMessageBox, QWidget, QDialog
 
 
 @pytest.mark.gui
@@ -225,3 +226,207 @@ def test_settings_browse_sets_path(qtbot, app, tmp_path, fresh_db, monkeypatch):
     )
     dlg._browse()
     assert dlg.path_edit.text().endswith("new_file.db")
+
+
+class _Host(QWidget):
+    def __init__(self, themes):
+        super().__init__()
+        self.themes = themes
+
+
+def _make_host_and_dialog(tmp_db_cfg, fresh_db):
+    # Create a real ThemeManager so we don't have to fake anything here
+    from PySide6.QtWidgets import QApplication
+
+    themes = ThemeManager(QApplication.instance(), ThemeConfig(theme=Theme.SYSTEM))
+    host = _Host(themes)
+    dlg = SettingsDialog(tmp_db_cfg, fresh_db, parent=host)
+    return host, dlg
+
+
+def _clear_qsettings_theme_to_system():
+    """Make the radio-button default deterministic across the full suite."""
+    s = get_settings()
+    s.clear()
+    s.setValue("ui/theme", "system")
+
+
+def test_default_theme_radio_is_system_checked(qtbot, tmp_db_cfg, fresh_db):
+    # Ensure no stray theme value from previous tests
+    _clear_qsettings_theme_to_system()
+
+    host, dlg = _make_host_and_dialog(tmp_db_cfg, fresh_db)
+    qtbot.addWidget(host)
+    qtbot.addWidget(dlg)
+    # With fresh settings (system), the 'system' radio should be selected
+    assert dlg.theme_system.isChecked()
+
+
+def test_save_selects_system_when_no_explicit_choice(
+    qtbot, tmp_db_cfg, fresh_db, monkeypatch
+):
+    host, dlg = _make_host_and_dialog(tmp_db_cfg, fresh_db)
+    qtbot.addWidget(dlg)
+    # Ensure neither dark nor light is checked so SYSTEM path is taken
+    dlg.theme_dark.setChecked(False)
+    dlg.theme_light.setChecked(False)
+    # This should not raise
+    dlg._save()
+
+
+def test_save_with_dark_selected(qtbot, tmp_db_cfg, fresh_db):
+    host, dlg = _make_host_and_dialog(tmp_db_cfg, fresh_db)
+    qtbot.addWidget(dlg)
+    dlg.theme_dark.setChecked(True)
+    dlg._save()
+
+
+def test_change_key_cancel_first_prompt(qtbot, tmp_db_cfg, fresh_db, monkeypatch):
+    host, dlg = _make_host_and_dialog(tmp_db_cfg, fresh_db)
+    qtbot.addWidget(dlg)
+
+    class P1:
+        def __init__(self, *a, **k):
+            pass
+
+        def exec(self):
+            return QDialog.Rejected
+
+        def key(self):
+            return ""
+
+    monkeypatch.setattr("bouquin.settings_dialog.KeyPrompt", P1)
+    dlg._change_key()  # returns early
+
+
+def test_change_key_cancel_second_prompt(qtbot, tmp_db_cfg, fresh_db, monkeypatch):
+    host, dlg = _make_host_and_dialog(tmp_db_cfg, fresh_db)
+    qtbot.addWidget(dlg)
+
+    class P1:
+        def __init__(self, *a, **k):
+            pass
+
+        def exec(self):
+            return QDialog.Accepted
+
+        def key(self):
+            return "abc"
+
+    class P2:
+        def __init__(self, *a, **k):
+            pass
+
+        def exec(self):
+            return QDialog.Rejected
+
+        def key(self):
+            return "abc"
+
+    # First call yields P1, second yields P2
+    seq = [P1, P2]
+
+    def _factory(*a, **k):
+        cls = seq.pop(0)
+        return cls(*a, **k)
+
+    monkeypatch.setattr("bouquin.settings_dialog.KeyPrompt", _factory)
+    dlg._change_key()  # returns early
+
+
+def test_change_key_empty_and_exception_paths(qtbot, tmp_db_cfg, fresh_db, monkeypatch):
+    host, dlg = _make_host_and_dialog(tmp_db_cfg, fresh_db)
+    qtbot.addWidget(dlg)
+
+    # Timer that auto-accepts any modal QMessageBox so we don't hang.
+    def _pump_boxes():
+        # Try both the active modal and the general top-level enumeration
+        m = QApplication.activeModalWidget()
+        if isinstance(m, QMessageBox):
+            m.accept()
+        for w in QApplication.topLevelWidgets():
+            if isinstance(w, QMessageBox):
+                w.accept()
+
+    timer = QTimer()
+    timer.setInterval(10)
+    timer.timeout.connect(_pump_boxes)
+    timer.start()
+
+    try:
+
+        class P1:
+            def __init__(self, *a, **k):
+                pass
+
+            def exec(self):
+                return QDialog.Accepted
+
+            def key(self):
+                return ""
+
+        class P2:
+            def __init__(self, *a, **k):
+                pass
+
+            def exec(self):
+                return QDialog.Accepted
+
+            def key(self):
+                return ""
+
+        seq = [P1, P2, P1, P2]
+
+        def _factory(*a, **k):
+            cls = seq.pop(0)
+            return cls(*a, **k)
+
+        monkeypatch.setattr("bouquin.settings_dialog.KeyPrompt", _factory)
+        # First run triggers empty-key warning path and return (auto-closed)
+        dlg._change_key()
+
+        # Now make rekey() raise to hit the except block (critical dialog)
+        def boom(*a, **k):
+            raise RuntimeError("nope")
+
+        dlg._db.rekey = boom
+
+        # Return a non-empty matching key twice
+        class P3:
+            def __init__(self, *a, **k):
+                pass
+
+            def exec(self):
+                return QDialog.Accepted
+
+            def key(self):
+                return "secret"
+
+        monkeypatch.setattr("bouquin.settings_dialog.KeyPrompt", lambda *a, **k: P3())
+        dlg._change_key()
+    finally:
+        timer.stop()
+
+
+def test_save_key_btn_clicked_cancel_flow(qtbot, tmp_db_cfg, fresh_db, monkeypatch):
+    host, dlg = _make_host_and_dialog(tmp_db_cfg, fresh_db)
+    qtbot.addWidget(dlg)
+
+    # Make sure we start with no key saved so it will prompt
+    dlg.key = ""
+
+    class P1:
+        def __init__(self, *a, **k):
+            pass
+
+        def exec(self):
+            return QDialog.Rejected
+
+        def key(self):
+            return ""
+
+    monkeypatch.setattr("bouquin.settings_dialog.KeyPrompt", P1)
+
+    dlg.save_key_btn.setChecked(True)  # toggles and calls handler
+    # Handler should have undone the checkbox back to False
+    assert not dlg.save_key_btn.isChecked()

tests/test_strings.py

@@ -0,0 +1,7 @@
+from bouquin import strings
+
+
+def test_load_strings_uses_system_locale_and_fallback():
+    # pass a bogus locale to trigger fallback-to-default
+    strings.load_strings("zz")
+    assert strings._("next")  # key exists in base translations

tests/test_theme.py

@@ -1,5 +1,6 @@
 import pytest
 from PySide6.QtGui import QPalette
+from PySide6.QtWidgets import QApplication, QCalendarWidget, QWidget
 
 from bouquin.theme import Theme, ThemeConfig, ThemeManager
 
@@ -19,3 +20,35 @@ def test_theme_manager_system_roundtrip(app, qtbot):
     cfg = ThemeConfig(theme=Theme.SYSTEM)
     mgr = ThemeManager(app, cfg)
     mgr.apply(cfg.theme)
+
+
+def _make_themes(theme):
+    app = QApplication.instance()
+    return ThemeManager(app, ThemeConfig(theme=theme))
+
+
+def test_register_and_restyle_calendar_and_overlay(qtbot):
+    themes = _make_themes(Theme.DARK)
+    cal = QCalendarWidget()
+    ov = QWidget()
+    ov.setObjectName("LockOverlay")
+    qtbot.addWidget(cal)
+    qtbot.addWidget(ov)
+
+    themes.register_calendar(cal)
+    themes.register_lock_overlay(ov)
+
+    # Force a restyle pass (covers the "is not None" branches)
+    themes._restyle_registered()
+
+
+def test_apply_dark_styles_cover_css_paths(qtbot):
+    themes = _make_themes(Theme.DARK)
+    cal = QCalendarWidget()
+    ov = QWidget()
+    ov.setObjectName("LockOverlay")
+    qtbot.addWidget(cal)
+    qtbot.addWidget(ov)
+
+    themes.register_calendar(cal)  # drives _apply_calendar_theme (dark path)
+    themes.register_lock_overlay(ov)  # drives _apply_lock_overlay_theme (dark path)