diff --git a/tests/helpers/fixtures.py b/tests/helpers/fixtures.py
index 2530a1ab6..eb8dd9a97 100644
--- a/tests/helpers/fixtures.py
+++ b/tests/helpers/fixtures.py
@@ -255,6 +255,14 @@ def app_stub(stubs):
     objreg.delete('app')
 
 
+@pytest.yield_fixture
+def completion_widget_stub(win_registry):
+    stub = unittest.mock.Mock()
+    objreg.register('completion', stub, scope='window', window=0)
+    yield stub
+    objreg.delete('completion', scope='window', window=0)
+
+
 @pytest.fixture(scope='session')
 def stubs():
     """Provide access to stub objects useful for testing."""
diff --git a/tests/helpers/stubs.py b/tests/helpers/stubs.py
index fa7f60fa5..f51ec4cf1 100644
--- a/tests/helpers/stubs.py
+++ b/tests/helpers/stubs.py
@@ -293,12 +293,13 @@ class FakeCommand:
     """A simple command stub which has a description."""
 
     def __init__(self, name='', desc='', hide=False, debug=False,
-                 deprecated=False):
+                 deprecated=False, completion=None):
         self.desc = desc
         self.name = name
         self.hide = hide
         self.debug = debug
         self.deprecated = deprecated
+        self.completion = completion
 
 
 class FakeTimer(QObject):
@@ -359,6 +360,34 @@ class FakeConfigType:
         self.complete = lambda: [(val, '') for val in valid_values]
 
 
+class FakeStatusbarCommand(QObject):
+
+    """Stub for the statusbar command prompt."""
+
+    got_cmd = pyqtSignal(str)
+    clear_completion_selection = pyqtSignal()
+    hide_completion = pyqtSignal()
+    update_completion = pyqtSignal()
+    show_cmd = pyqtSignal()
+    hide_cmd = pyqtSignal()
+    textChanged = pyqtSignal()
+
+    def __init__(self, parent=None, name=None):
+        super().__init__(parent)
+        self._cursor_pos = 0
+        self._text = ""
+        self.cursorPosition = lambda: self._cursor_pos
+        self.text = lambda: self._text
+        self.prefix = lambda: self._text[0]
+        self.setFocus = lambda: None
+
+    def setText(self, x):
+        self._text = x
+
+    def setCursorPosition(self, x):
+        self._cursor_pos = x
+
+
 class ConfigStub(QObject):
 
     """Stub for the config module.
diff --git a/tests/unit/completion/test_completer.py b/tests/unit/completion/test_completer.py
new file mode 100644
index 000000000..b006a72ee
--- /dev/null
+++ b/tests/unit/completion/test_completer.py
@@ -0,0 +1,136 @@
+# vim: ft=python fileencoding=utf-8 sts=4 sw=4 et:
+
+# Copyright 2016 Ryan Roden-Corrent (rcorre) <ryan@rcorre.net>
+#
+# This file is part of qutebrowser.
+#
+# qutebrowser is free software: you can redistribute it and/or modify
+# it under the terms of the GNU General Public License as published by
+# the Free Software Foundation, either version 3 of the License, or
+# (at your option) any later version.
+#
+# qutebrowser is distributed in the hope that it will be useful,
+# but WITHOUT ANY WARRANTY; without even the implied warranty of
+# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+# GNU General Public License for more details.
+#
+# You should have received a copy of the GNU General Public License
+# along with qutebrowser.  If not, see <http://www.gnu.org/licenses/>.
+
+"""Tests for the Completer Object."""
+
+from unittest.mock import Mock
+
+import pytest
+from PyQt5.QtGui import QStandardItemModel
+
+from qutebrowser.completion.completer import Completer
+from qutebrowser.utils.usertypes import Completion
+
+
+class FakeCompletionModel(QStandardItemModel):
+
+    """Stub for a completion model."""
+
+    DUMB_SORT = Mock()
+
+    def __init__(self, kind, parent=None):
+        super().__init__(parent)
+        self.kind = kind
+
+
+@pytest.fixture
+def cmd(stubs):
+    """Create the statusbar command prompt the completer uses."""
+    return stubs.FakeStatusbarCommand()
+
+
+@pytest.fixture
+def completer(qtbot, cmd, config_stub):
+    """Create the completer used for testing."""
+    config_stub.data = {'completion': {'auto-open': False}}
+    return Completer(cmd, 0)
+
+
+@pytest.fixture
+def instances(monkeypatch):
+    """Mock the instances module so get returns a fake completion model."""
+    # populate a model for each completion type, with a nested structure for
+    # option and value completion
+    instances = {kind: FakeCompletionModel(kind) for kind in Completion}
+    instances[Completion.option] = {
+        'general': FakeCompletionModel(Completion.option),
+    }
+    instances[Completion.value] = {
+        'general': {
+            'ignore-case': FakeCompletionModel(Completion.value),
+        }
+    }
+    monkeypatch.setattr('qutebrowser.completion.completer.instances',
+                        instances)
+    return instances
+
+
+@pytest.fixture
+def cmdutils_patch(monkeypatch, stubs):
+    """Patch the cmdutils module to provide fake commands."""
+    cmds = {
+        'set': [Completion.section, Completion.option, Completion.value],
+        'help': [Completion.helptopic],
+        'quickmark-load': [Completion.quickmark_by_name],
+        'bookmark-load': [Completion.bookmark_by_url],
+        'open': [Completion.url],
+        'buffer': [Completion.tab],
+        'session-load': [Completion.sessions],
+        'bind': [Completion.empty, Completion.command],
+    }
+    cmd_utils = stubs.FakeCmdUtils({
+        name: stubs.FakeCommand(completion=compl)
+        for name, compl in cmds.items()
+    })
+    monkeypatch.setattr('qutebrowser.completion.completer.cmdutils',
+                        cmd_utils)
+    return cmd_utils
+
+
+@pytest.mark.parametrize('txt, expected', [
+    (':nope|', Completion.command),
+    (':nope |', None),
+    (':set |', Completion.section),
+    (':set gen|', Completion.section),
+    (':set general |', Completion.option),
+    (':set what |', None),
+    (':set general ignore-case |', Completion.value),
+    (':set general huh |', None),
+    (':help |', Completion.helptopic),
+    (':quickmark-load |', Completion.quickmark_by_name),
+    (':bookmark-load |', Completion.bookmark_by_url),
+    (':open |', Completion.url),
+    (':buffer |', Completion.tab),
+    (':session-load |', Completion.sessions),
+    (':bind |', Completion.empty),
+    (':bind <c-x> |', Completion.command),
+    (':bind <c-x> foo|', Completion.command),
+    (':bind <c-x>| foo', Completion.empty),
+    (':set| general ', Completion.command),
+    (':|set general ', Completion.command),
+    (':set gene|ral ignore-case', Completion.section),
+    (':|', Completion.command),
+    (':   |', Completion.command),
+    (':bookmark-load      |', Completion.bookmark_by_url),
+])
+def test_update_completion(txt, expected, cmd, completer, instances,
+                           cmdutils_patch, completion_widget_stub):
+    """Test setting the completion widget's model based on command text."""
+    # this test uses | as a placeholder for the current cursor position
+    cursor_pos = txt.index('|')
+    cmd.setText(txt.replace('|', ''))
+    cmd.setCursorPosition(cursor_pos)
+    completer.update_completion()
+    if expected is None:
+        assert not completion_widget_stub.set_model.called
+    else:
+        assert completion_widget_stub.set_model.call_count == 1
+        arg = completion_widget_stub.set_model.call_args[0][0]
+        # the outer model is just for sorting; srcmodel is the completion model
+        assert arg.srcmodel.kind == expected