FIX: files setting the toolkit crashed nosetest

There were sub-modules and tests setting the
backend explicitly, which crashed nosetest.

- moved all two tests to the traitsui.tests module

- setup.cfg tells nose where to look

setup.cfg

@@ -0,0 +1,2 @@
+[nosetests]
+where=traitsui/tests

traitsui/tests/__init__.py

@@ -0,0 +1,10 @@
+# Run tests using nose:
+#   $ nosetests -v
+#
+# The tests that are not compatible with the selected toolkit will be skipped
+# (resulting in 'S' characters in the report). To test different backend,
+# you should set the backend using the environment variable ETS_TOOLKIT:
+#
+#   $ ETS_TOOLKIT='qt4' nosetests -v
+#   $ ETS_TOOLKIT='wx' nosetests -v
+#   $ ETS_TOOLKIT='null' nosetests -v

traitsui/tests/_tools.py

@@ -86,12 +86,19 @@ def test_func():
 #: Return True if current backend is 'qt4'
 is_current_backend_qt4 = partial(_is_current_backend, backend_name='qt4')
 
+#: Return True if current backend is 'null'
+is_current_backend_null = partial(_is_current_backend, backend_name='null')
+
+
 #: Test decorator: Skip test if backend is not 'wx'
 skip_if_not_wx = partial(skip_if_not_backend, backend_name='wx')
 
 #: Test decorator: Skip test if backend is not 'qt4'
 skip_if_not_qt4 = partial(skip_if_not_backend, backend_name='qt4')
 
+#: Test decorator: Skip test if backend is not 'null'
+skip_if_not_null = partial(skip_if_not_backend, backend_name='null')
+
 
 def count_calls(func):
     """Decorator that stores the number of times a function is called.
@@ -192,7 +199,7 @@ def destroy_wrapped():
 
 
 def wx_find_event_by_number(evt_num):
-    """Find all wx event names that correspond to a ceratin event number.
+    """Find all wx event names that correspond to a certain event number.
 
     Example:
 

traitsui/tests/test_csv_editor.py → traitsui/tests/editors/test_csv_editor.py

@@ -21,7 +21,7 @@
 from traitsui.editors.csv_list_editor import CSVListEditor
 import traitsui.editors.csv_list_editor as csv_list_editor
 
-from _tools import *
+from traitsui.tests._tools import *
 
 
 class ListOfFloats(HasTraits):

traitsui/editors/tests/test_default_override.py → traitsui/tests/editors/test_default_override.py

@@ -1,9 +1,7 @@
 
-from __future__ import absolute_import
-
 from nose.tools import assert_equals
 
-from ...api import DefaultOverride, EditorFactory
+from traitsui.api import DefaultOverride, EditorFactory
 from traits.api import HasTraits, Int
 
 
@@ -33,45 +31,47 @@ def create_editor(self):
 class Dummy(HasTraits):
     x = NewInt()
 
-object = Dummy()
+
+dummy_object = Dummy()
 do = DefaultOverride(x=15, y=25, format_str='%r')
 
+
 def test_simple_override():
-    editor_name, editor, ui, obj, name, description, parent = do.simple_editor('ui', object, 'x', 'description', 'parent')
+    editor_name, editor, ui, obj, name, description, parent = do.simple_editor('ui', dummy_object, 'x', 'description', 'parent')
     assert_equals(editor_name, 'simple_editor')
     assert_equals(editor.x, 15)
     assert_equals(editor.y, 25)
-    assert_equals(obj, object)
+    assert_equals(obj, dummy_object)
     assert_equals(name, 'x')
     assert_equals(description, 'description')
     assert_equals(parent, 'parent')
 
 def test_text_override():
-    editor_name, editor, ui, obj, name, description, parent = do.text_editor('ui', object, 'x', 'description', 'parent')
+    editor_name, editor, ui, obj, name, description, parent = do.text_editor('ui', dummy_object, 'x', 'description', 'parent')
     assert_equals(editor_name, 'text_editor')
     assert_equals(editor.x, 15)
     assert_equals(editor.y, 25)
-    assert_equals(obj, object)
+    assert_equals(obj, dummy_object)
     assert_equals(name, 'x')
     assert_equals(description, 'description')
     assert_equals(parent, 'parent')
 
 def test_custom_override():
-    editor_name, editor, ui, obj, name, description, parent = do.custom_editor('ui', object, 'x', 'description', 'parent')
+    editor_name, editor, ui, obj, name, description, parent = do.custom_editor('ui', dummy_object, 'x', 'description', 'parent')
     assert_equals(editor_name, 'custom_editor')
     assert_equals(editor.x, 15)
     assert_equals(editor.y, 25)
-    assert_equals(obj, object)
+    assert_equals(obj, dummy_object)
     assert_equals(name, 'x')
     assert_equals(description, 'description')
     assert_equals(parent, 'parent')
 
 def test_readonly_override():
-    editor_name, editor, ui, obj, name, description, parent = do.readonly_editor('ui', object, 'x', 'description', 'parent')
+    editor_name, editor, ui, obj, name, description, parent = do.readonly_editor('ui', dummy_object, 'x', 'description', 'parent')
     assert_equals(editor_name, 'readonly_editor')
     assert_equals(editor.x, 15)
     assert_equals(editor.y, 25)
-    assert_equals(obj, object)
+    assert_equals(obj, dummy_object)
     assert_equals(name, 'x')
     assert_equals(description, 'description')
     assert_equals(parent, 'parent')

traitsui/tests/test_range_editor_spinner.py → traitsui/tests/editors/test_range_editor_spinner.py

@@ -31,7 +31,7 @@
 from traitsui.view import View
 from traitsui.editors.range_editor import RangeEditor
 
-from _tools import *
+from traitsui.tests._tools import *
 
 
 class NumberWithSpinnerEditor(HasTraits):

traitsui/tests/test_range_editor_text.py → traitsui/tests/editors/test_range_editor_text.py

@@ -25,7 +25,7 @@
 from traitsui.view import View
 from traitsui.editors.range_editor import RangeEditor
 
-from _tools import *
+from traitsui.tests._tools import *
 
 
 class NumberWithTextEditor(HasTraits):

traitsui/null/tests/test_font_trait.py → traitsui/tests/null_backend/test_font_trait.py

@@ -3,17 +3,18 @@
 
 from traits.api import HasTraits, Font
 
-from traits.etsconfig.api import ETSConfig
-ETSConfig.toolkit = 'null'
+from traitsui.tests._tools import *
 
 
+@skip_if_not_null
 def test_font_trait_default():
     class Foo(HasTraits):
         font = Font()
     f = Foo()
     assert_equals(f.font, '10 pt Arial')
 
 
+@skip_if_not_null
 def test_font_trait_examples():
     """
     An assigned font string is parsed, and the substrings are