diff --git a/qutebrowser/keyinput/keyutils.py b/qutebrowser/keyinput/keyutils.py
index ddc78b2b4..fd973eb80 100644
--- a/qutebrowser/keyinput/keyutils.py
+++ b/qutebrowser/keyinput/keyutils.py
@@ -391,7 +391,7 @@ class KeySequence:
             return QKeySequence.ExactMatch
         elif len(self._sequences) < len(other._sequences):
             return QKeySequence.PartialMatch
-        else:
+        else:  # pragma: no cover
             assert False, (self, other)
 
     def append_event(self, ev):
diff --git a/scripts/dev/check_coverage.py b/scripts/dev/check_coverage.py
index 0e79a6e02..b40188429 100644
--- a/scripts/dev/check_coverage.py
+++ b/scripts/dev/check_coverage.py
@@ -86,6 +86,8 @@ PERFECT_FILES = [
 
     ('tests/unit/keyinput/test_basekeyparser.py',
      'keyinput/basekeyparser.py'),
+    ('tests/unit/keyinput/test_keyutils.py',
+     'keyinput/keyutils.py'),
 
     ('tests/unit/misc/test_autoupdate.py',
      'misc/autoupdate.py'),
diff --git a/tests/unit/keyinput/test_keyutils.py b/tests/unit/keyinput/test_keyutils.py
index 0f13c762d..3f03f883d 100644
--- a/tests/unit/keyinput/test_keyutils.py
+++ b/tests/unit/keyinput/test_keyutils.py
@@ -320,6 +320,30 @@ class TestKeySequence:
         configured = keyutils.KeySequence.parse(configured)
         assert entered.matches(configured) == expected
 
+    @pytest.mark.parametrize('old, key, modifiers, text, expected', [
+        ('a', Qt.Key_B, Qt.NoModifier, 'b', 'ab'),
+        ('a', Qt.Key_B, Qt.ShiftModifier, 'B', 'aB'),
+        ('a', Qt.Key_B, Qt.ControlModifier | Qt.ShiftModifier, 'B',
+         'a<Ctrl+Shift+b>'),
+
+        # Modifier stripping with symbols
+        ('', Qt.Key_Colon, Qt.NoModifier, ':', ':'),
+        ('', Qt.Key_Colon, Qt.ShiftModifier, ':', ':'),
+        ('', Qt.Key_Colon, Qt.ControlModifier | Qt.ShiftModifier, ':',
+         '<Ctrl+Shift+:>'),
+
+        # Handling of Backtab
+        ('', Qt.Key_Backtab, Qt.NoModifier, '', '<Backtab>'),
+        ('', Qt.Key_Backtab, Qt.ShiftModifier, '', '<Shift+Tab>'),
+        ('', Qt.Key_Backtab, Qt.ControlModifier | Qt.ShiftModifier, '',
+         '<Control+Shift+Tab>'),
+    ])
+    def test_append_event(self, old, key, modifiers, text, expected):
+        seq = keyutils.KeySequence.parse(old)
+        event = QKeyEvent(QKeyEvent.KeyPress, key, modifiers, text)
+        new = seq.append_event(event)
+        assert new == keyutils.KeySequence.parse(expected)
+
     @pytest.mark.parametrize('keystr, expected', [
         ('<Control-x>', keyutils.KeySequence(Qt.ControlModifier | Qt.Key_X)),
         ('<Meta-x>', keyutils.KeySequence(Qt.MetaModifier | Qt.Key_X)),