from subprocess import call
import unittest.mock
 
class Foo():
 
	def __init__(self, func):
		self._func = func
 
	def foo(self):
		self._func('pwd')
		return "ok"
 
class TestStringMethods(unittest.TestCase):
 
	def setUp(self):
		# oczywiście ta funkcja może (a nawet powinna) być gdzieś indziej
		def mock_call(cmd):
			if cmd == 'pwd':
				return '/etc'
			else:
				raise NotImplementedError()
		self.foo = Foo(func=mock_call)
 
	def test_foo(self):
		self.assertEqual(self.foo.foo(), "ok")
 
if __name__ == '__main__':
	unittest.main()

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