diff --git a/qutebrowser/keyinput/basekeyparser.py b/qutebrowser/keyinput/basekeyparser.py
index 2b41dac65..a2eef47c7 100644
--- a/qutebrowser/keyinput/basekeyparser.py
+++ b/qutebrowser/keyinput/basekeyparser.py
@@ -352,7 +352,7 @@ class BaseKeyParser(QObject):
     def on_keyconfig_changed(self, mode):
         """Re-read the config if a key binding was changed."""
         if self._modename is None:
-            raise AttributeError("on_keyconfig_changed called but no section "
+            raise AssertionError("on_keyconfig_changed called but no section "
                                  "defined!")
         if mode == self._modename:
             self.read_config()
diff --git a/tests/unit/keyinput/test_basekeyparser.py b/tests/unit/keyinput/test_basekeyparser.py
index 9abba0e9c..85fd7953d 100644
--- a/tests/unit/keyinput/test_basekeyparser.py
+++ b/tests/unit/keyinput/test_basekeyparser.py
@@ -25,6 +25,7 @@ from unittest import mock
 
 from PyQt5.QtCore import Qt
 import pytest
+import pytestqt
 
 from qutebrowser.keyinput import basekeyparser
 from qutebrowser.utils import utils
@@ -92,6 +93,29 @@ class TestReadConfig:
         assert 'foo' in kp.bindings
         assert 'ctrl+x' in kp.special_bindings
 
+    def test_on_keyconfig_changed(self):
+        """Test the handling of changes in the config."""
+        kp = basekeyparser.BaseKeyParser(0, supports_count=False,
+                                         supports_chains=False)
+        kp.read_config = mock.Mock()
+        kp._modename = None
+
+        # No config set so self._modename is None
+        with pytest.raises(AssertionError) as excinfo:
+            kp.on_keyconfig_changed("normal")
+        assert "on_keyconfig_changed called but no section defined!" in str(
+            excinfo.value)
+        assert not kp.read_config.called
+
+        kp._modename = "normal"
+        kp.on_keyconfig_changed("normal2")
+        # Modenames are not equal so read_config() should not be called
+        assert not kp.read_config.called
+
+        kp.on_keyconfig_changed("normal")
+        # Both modenames equal so read_config() should be called
+        assert kp.read_config.called
+
 
 @pytest.mark.usefixtures('mock_timer')
 class TestSpecialKeys:
@@ -233,6 +257,22 @@ class TestKeyChain:
         self.kp.handle(fake_keyevent_factory(Qt.Key_C, text='c'))
         assert self.kp._keystring == ''
 
+    def test_delayed_exec(self, fake_keyevent_factory, config_stub,
+                          monkeypatch, qtbot):
+        """Test delayec execute for ambiguous keychain."""
+        config_stub.data = CONFIG
+        monkeypatch.setattr('qutebrowser.keyinput.basekeyparser.config',
+                            config_stub)
+        timer = self.kp._ambiguous_timer
+        # 'a' is an ambiguous result.
+        self.kp.handle(fake_keyevent_factory(Qt.Key_A, text='a'))
+        assert not self.kp.execute.called
+        assert timer.isActive()
+        # We wait for the timeout to occur.
+        with qtbot.waitSignal(self.kp.keystring_updated, raising=True):
+            pass
+        assert self.kp.execute.called
+
 
 @pytest.mark.usefixtures('mock_timer')
 class TestCount: