from unittest import TestCase

from mmeter.mmeter import App


class TestAppInstance(TestCase):

	def setUp(self):
		self.app = App()

	def tearDown(self):
		self.app.destroy()

	def test_instance(self):
		self.assertIsInstance(self.app, App)


if __name__ == '__main__':
	unittest.main()

@@ -1,12 +1,35 @@
+from tkinter import Tk%0A
 from unittes
@@ -123,32 +123,51 @@
 ef setUp(self):%0A
+%09%09self.root = Tk()%0A
 %09%09self.app = App
@@ -167,16 +167,25 @@
 p = App(
+self.root
 )%0A%0A%09def 

Change test.