diff --git a/.travis.yml b/.travis.yml
index 49c5808..e868fbe 100644
--- a/.travis.yml
+++ b/.travis.yml
@@ -4,7 +4,6 @@ language: python
 python:
   - '3.5'
 install:
- - sudo apt-get install python-qt4 pyqt4-dev-tools
  - pip install --quiet -r ci/requirements.txt
  - git clone https://github.com/QubesOS/qubes-builder ~/qubes-builder
 script:
diff --git a/qubesmanager/bootfromdevice.py b/qubesmanager/bootfromdevice.py
index 975364e..ab54b98 100644
--- a/qubesmanager/bootfromdevice.py
+++ b/qubesmanager/bootfromdevice.py
@@ -20,10 +20,9 @@
 import sys
 import subprocess
 from . import utils
-from . import firewall
 from . import ui_bootfromdevice  # pylint: disable=no-name-in-module
 from PyQt4 import QtGui, QtCore  # pylint: disable=import-error
-import qubesadmin.tools.qvm_start as qvm_start
+from qubesadmin import tools
 
 
 class VMBootFromDeviceWindow(ui_bootfromdevice.Ui_BootDialog, QtGui.QDialog):
@@ -63,7 +62,7 @@ class VMBootFromDeviceWindow(ui_bootfromdevice.Ui_BootDialog, QtGui.QDialog):
                 self.tr("ERROR!"),
                 self.tr("No file or block device selected; please select one."))
             return
-        qvm_start.main(['--cdrom', cdrom_location, self.vm.name])
+        tools.qvm_start.main(['--cdrom', cdrom_location, self.vm.name])
 
     def __init_buttons__(self):
         self.fileVM.setEnabled(False)
@@ -111,7 +110,7 @@ class VMBootFromDeviceWindow(ui_bootfromdevice.Ui_BootDialog, QtGui.QDialog):
             self.pathText.setText(new_path)
 
 
-parser = firewall.qubesadmin.tools.QubesArgumentParser(vmname_nargs=1)
+parser = tools.QubesArgumentParser(vmname_nargs=1)
 
 def main(args=None):
     args = parser.parse_args(args)
diff --git a/qubesmanager/firewall.py b/qubesmanager/firewall.py
index 88ef311..d8a3d1c 100644
--- a/qubesmanager/firewall.py
+++ b/qubesmanager/firewall.py
@@ -148,14 +148,13 @@ class QubesFirewallRulesModel(QtCore.QAbstractItemModel):
             r"(?P<name>[a-z][a-z0-9-]+)\s+(?P<port>[0-9]+)/"
             r"(?P<protocol>[a-z]+)",
             re.IGNORECASE)
-        file = open('/etc/services', 'r')
-        for line in file:
-            match = pattern.match(line)
-            if match is not None:
-                service = match.groupdict()
-                self.__services.append(
-                    (service["name"], int(service["port"]),))
-        file.close()
+        with open('/etc/services', 'r') as file:
+            for line in file:
+                match = pattern.match(line)
+                if match is not None:
+                    service = match.groupdict()
+                    self.__services.append(
+                        (service["name"], int(service["port"]),))
 
         self.fw_changed = False
         self.allow = None # is the default policy allow or deny
@@ -165,8 +164,8 @@ class QubesFirewallRulesModel(QtCore.QAbstractItemModel):
 
     def sort(self, idx, order):
         rev = (order == QtCore.Qt.AscendingOrder)
-        self.children.sort(key=lambda x: self.get_column_string(idx, x)
-                           , reverse=rev)
+        self.children.sort(key=lambda x: self.get_column_string(idx, x),
+                           reverse=rev)
 
         index1 = self.createIndex(0, 0)
         index2 = self.createIndex(len(self) - 1, len(self.__column_names) - 1)
@@ -388,7 +387,7 @@ class QubesFirewallRulesModel(QtCore.QAbstractItemModel):
                         self.tr("Invalid port or service"),
                         self.tr("Port number or service '{0}' is invalid.")
                                         .format(service))
-            elif service is not None and service != "":
+            elif service:
                 try:
                     rule.dstports = service
                 except (TypeError, ValueError):
@@ -425,9 +424,7 @@ class QubesFirewallRulesModel(QtCore.QAbstractItemModel):
     # pylint: disable=invalid-name,no-self-use
     def hasChildren(self, index=QtCore.QModelIndex()):
         parent_item = index.internalPointer()
-        if parent_item is not None:
-            return False
-        return True
+        return parent_item is None
 
     def data(self, index, role=QtCore.Qt.DisplayRole):
         if index.isValid() and role == QtCore.Qt.DisplayRole:
diff --git a/qubesmanager/global_settings.py b/qubesmanager/global_settings.py
index 0526546..c779326 100644
--- a/qubesmanager/global_settings.py
+++ b/qubesmanager/global_settings.py
@@ -158,7 +158,7 @@ class GlobalSettingsWindow(ui_globalsettingsdlg.Ui_GlobalSettings,
     def __init_kernel_defaults__(self):
         kernel_list = []
         # TODO system_path["qubes_kernels_base_dir"]
-        # idea: qubes.pulls['linux-kernel'].volumes
+        # idea: qubes.pools['linux-kernel'].volumes
         for k in os.listdir('/var/lib/qubes/vm-kernels'):
             kernel_list.append(k)
 
diff --git a/qubesmanager/settings.py b/qubesmanager/settings.py
index 6fb75f2..fa1305b 100755
--- a/qubesmanager/settings.py
+++ b/qubesmanager/settings.py
@@ -31,6 +31,7 @@ import traceback
 import os
 import sys
 from qubesadmin.tools import QubesArgumentParser
+from qubesadmin import devices
 import qubesadmin.exc
 
 from . import utils
@@ -665,7 +666,7 @@ class VMSettingsWindow(ui_settingsdlg.Ui_SettingsDialog, QtGui.QDialog):
                     for i in range(self.dev_list.selected_list.count())]
             for ident in new:
                 if ident not in old:
-                    ass = firewall.qubesadmin.devices.DeviceAssignment(
+                    ass = devices.DeviceAssignment(
                         self.vm.app.domains['dom0'],
                         ident.replace(':', '_'),
                         persistent=True)
diff --git a/test-packages/qubesadmin/DEFAULT.py b/test-packages/qubesadmin/DEFAULT.py
deleted file mode 100644
index c3b69bd..0000000
--- a/test-packages/qubesadmin/DEFAULT.py
+++ /dev/null
@@ -1 +0,0 @@
-### mock qubesadmin.DEFAULT module
\ No newline at end of file
diff --git a/test-packages/qubesadmin/__init__.py b/test-packages/qubesadmin/__init__.py
index d9c1b4d..1801453 100644
--- a/test-packages/qubesadmin/__init__.py
+++ b/test-packages/qubesadmin/__init__.py
@@ -1,2 +1,4 @@
 class Qubes(object):
-    pass
\ No newline at end of file
+    pass
+
+DEFAULT = object()
diff --git a/test-packages/qubesadmin/devices.py b/test-packages/qubesadmin/devices.py
index e31e5c3..be5de38 100644
--- a/test-packages/qubesadmin/devices.py
+++ b/test-packages/qubesadmin/devices.py
@@ -1,4 +1,4 @@
 ### mock qubesadmin.devices module
 
 class DeviceAssignment(object):
-    pass
\ No newline at end of file
+    pass
diff --git a/test-packages/qubesadmin/exc.py b/test-packages/qubesadmin/exc.py
index 78835e2..087af2a 100644
--- a/test-packages/qubesadmin/exc.py
+++ b/test-packages/qubesadmin/exc.py
@@ -1,4 +1,4 @@
 ### mock qubesadmin.exc module
 
 class QubesException(BaseException):
-    pass
\ No newline at end of file
+    pass
diff --git a/test-packages/qubesadmin/firewall.py b/test-packages/qubesadmin/firewall.py
index 07a5151..e83c19f 100644
--- a/test-packages/qubesadmin/firewall.py
+++ b/test-packages/qubesadmin/firewall.py
@@ -1,4 +1,4 @@
 ### mock qubesadmin.firewall module
 
 class Rule(object):
-    pass
\ No newline at end of file
+    pass
diff --git a/test-packages/qubesadmin/tools/qvm_start.py b/test-packages/qubesadmin/tools/qvm_start.py
index 4385323..f04be20 100644
--- a/test-packages/qubesadmin/tools/qvm_start.py
+++ b/test-packages/qubesadmin/tools/qvm_start.py
@@ -1,4 +1,4 @@
 ### mock qvm_start module
 
 def main(*args, **kwargs):
-    pass
\ No newline at end of file
+    pass
diff --git a/test-packages/qubesadmin/utils.py b/test-packages/qubesadmin/utils.py
index bcf4711..afb7725 100644
--- a/test-packages/qubesadmin/utils.py
+++ b/test-packages/qubesadmin/utils.py
@@ -4,4 +4,4 @@ def parse_size(*args, **kwargs):
     return args[0]
 
 def updates_vms_status(*args, **kwargs):
-    return args[0]
\ No newline at end of file
+    return args[0]