Add alias completion

Partially fixes #32.

qutebrowser/completion/completer.py

@@ -90,7 +90,12 @@ def _get_new_completion(self, before_cursor, under_cursor):
             log.completion.debug('Starting command completion')
             return miscmodels.command
         try:
-            cmd = objects.commands[before_cursor[0]]
+            cmdname = before_cursor[0]
+            if before_cursor[0] in config.cache['aliases']:
+                cmdname = config.cache['aliases'][before_cursor[0]].split(
+                    maxsplit=1)[0]
+
+            cmd = objects.commands[cmdname]
         except KeyError:
             log.completion.debug("No completion for unknown command: {}"
                                  .format(before_cursor[0]))

tests/unit/completion/test_completer.py

@@ -189,12 +189,18 @@ def _set_cmd_prompt(cmd, txt):
     (':config-cycle option |', 'value', '', ['option']),
     (':config-cycle option one |', 'value', '', ['option', 'one']),
     (':config-cycle option one two |', 'value', '', ['option', 'one', 'two']),
+        (':openalias |', 'url', '', []),
+        (':bindalias |', None, '', []),
+        (':bindalias <c-x> |', 'command', '', ['<c-x>']),
+        (':bindalias <c-x> foo|', 'command', 'foo', ['<c-x>']),
+        (':bindalias <c-x>| foo', None, '<c-x>', []),
 ])
 def test_update_completion(txt, kind, pattern, pos_args, status_command_stub,
                            completer_obj, completion_widget_stub, config_stub,
                            key_config_stub):
     """Test setting the completion widget's model based on command text."""
     # this test uses | as a placeholder for the current cursor position
+    config_stub.val.aliases = {"bindalias": "bind", "openalias": "open -t"}
     _set_cmd_prompt(status_command_stub, txt)
     completer_obj.schedule_completion_update()
     if kind is None: