unittests are not run

Take this sample code from https://docs.python.org/3/library/unittest.html
```python
import unittest

class TestStringMethods(unittest.TestCase):

def test_upper(self):
self.assertEqual('foo'.upper(), 'FOO')

def test_isupper(self):
self.assertTrue('FOO'.isupper())
self.assertFalse('Foo'.isupper())

def test_split(self):
s = 'hello world'
self.assertEqual(s.split(), ['hello', 'world'])
# check that s.split fails when the separator is not a string
with self.assertRaises(TypeError):
s.split(2)

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

AREPL says:

> Ran 0 tests in 0.000s

Expected result: it runs 3 tests