def test_first_str_empty_other_non_emtpy(self):
string1 = ""
string2 = "napis"
string3 = merge_strings(string1, string2)
self.assertEqual(string3, "napis")
def test_first_str_longer_than_other(self):
string1 = "potezny"
string2 = "napis"
string3 = merge_strings(string1, string2)
self.assertEqual(string3, "pnoatpeizsny")
def test_strings_with_the_same_length(self):
string1 = "mocny"
string2 = "napis"
string3 = merge_strings(string1, string2)
self.assertEqual(string3, "mnoacpniys")
def test_first_str_shorter_than_other(self):
string1 = "moc"
string2 = "napis"
string3 = merge_strings(string1, string2)
self.assertEqual(string3, "mnoacpis")
def test_both_strings_are_empty(self):
string1 = ""
string2 = ""
string3 = merge_strings(string1, string2)
self.assertEqual(string3, "")