diff --git a/test/gtk/assistant.py b/test/gtk/assistant.py
index 74402040dc7dc2074de912fbe2b2d6b3aa760516..17a359b35aa81679a3e5503164ed96de99e70ec3 100644
--- a/test/gtk/assistant.py
+++ b/test/gtk/assistant.py
@@ -4,6 +4,9 @@
 
 from gajim.common.const import CSSPriority
 
+from gajim import gui
+gui.init('gtk')
+
 from gajim.gui.assistant import Assistant
 from gajim.gui.assistant import Page
 
diff --git a/test/gtk/certificate_dialog.py b/test/gtk/certificate_dialog.py
index dc991157965bc071bf5ed3d52beede6081d447f2..534fe55007b8f2df4d6b8e8573d573cab6d38706 100644
--- a/test/gtk/certificate_dialog.py
+++ b/test/gtk/certificate_dialog.py
@@ -4,6 +4,9 @@
 
 import OpenSSL
 
+from gajim import gui
+gui.init('gtk')
+
 from test.gtk import util
 from gajim.common.const import CSSPriority
 from gajim.gui.dialogs import CertificateDialog
diff --git a/test/gtk/dataform.py b/test/gtk/dataform.py
index f135dabd0efa29264df37628d3b3d49d902c09c0..51e98ea593ef3fdf4d6a7ab421bea160e2153f4a 100644
--- a/test/gtk/dataform.py
+++ b/test/gtk/dataform.py
@@ -4,6 +4,9 @@
 import nbxmpp
 from nbxmpp.modules.dataforms import extend_form
 
+from gajim import gui
+gui.init('gtk')
+
 from gajim.gui.dataform import DataFormWidget
 from gajim.common.const import CSSPriority
 from gajim.common import app
diff --git a/test/gtk/fake_dataform.py b/test/gtk/fake_dataform.py
index be776a0baf2f5ca6354266659cc7340f0a112e16..aa94d5317e6c55e3627cd3031de6653d5368e594 100644
--- a/test/gtk/fake_dataform.py
+++ b/test/gtk/fake_dataform.py
@@ -1,5 +1,8 @@
 from gi.repository import Gtk
 
+from gajim import gui
+gui.init('gtk')
+
 from gajim.gui.dataform import FakeDataFormWidget
 from gajim.common.const import CSSPriority
 
diff --git a/test/gtk/groupchat_info.py b/test/gtk/groupchat_info.py
index 689452dc145fefd0da9fd2d56a17cdd1b00d7d9f..2399c422d0d011c829fda0e73f851f518f95be52 100644
--- a/test/gtk/groupchat_info.py
+++ b/test/gtk/groupchat_info.py
@@ -9,6 +9,9 @@
 
 from gajim.common.const import CSSPriority
 
+from gajim import gui
+gui.init('gtk')
+
 from test.gtk import util
 from gajim.gui.groupchat_info import GroupChatInfoScrolled
 
diff --git a/test/gtk/htmltextview.py b/test/gtk/htmltextview.py
index cdc28fa51659ff90aa382e4bdbc6b5ccd442f91b..4d603f103ed871ce6032605f2aea1c4b12b49b29 100644
--- a/test/gtk/htmltextview.py
+++ b/test/gtk/htmltextview.py
@@ -9,6 +9,9 @@
 configpaths.init()
 from gajim.common.helpers import AdditionalDataDict
 
+from gajim import gui
+gui.init('gtk')
+
 from gajim.conversation_textview import ConversationTextview
 from gajim.gui_interface import Interface
 
diff --git a/test/gtk/ssl_error_dialog.py b/test/gtk/ssl_error_dialog.py
index 10a5ca658950626394ce58351b7719808c7fded7..eba50f88e9b93cb95c04a0ec30a4fe0d77d03315 100644
--- a/test/gtk/ssl_error_dialog.py
+++ b/test/gtk/ssl_error_dialog.py
@@ -4,6 +4,9 @@
 
 import OpenSSL
 
+from gajim import gui
+gui.init('gtk')
+
 from test.gtk import util
 from gajim.common.const import CSSPriority
 from gajim.gui.ssl_error_dialog import SSLErrorDialog
diff --git a/test/no_gui/unit/test_nick_completion.py b/test/no_gui/unit/test_nick_completion.py
index 0eb75ba43f06dbde4aa504c51e1cbb751fa4b50b..43d8d60a1b16a3940d30d3befefd161c86c7c7d3 100644
--- a/test/no_gui/unit/test_nick_completion.py
+++ b/test/no_gui/unit/test_nick_completion.py
@@ -1,5 +1,7 @@
 import unittest
 
+from gajim import gui
+gui.init('gtk')
 from gajim.gui.util import NickCompletionGenerator
 
 class Test(unittest.TestCase):