old_contents: 
  import unittest
  from GeneratePrimeNumbers import GeneratePrimeNumbers
  
  
  class TestPrimeGenerator(unittest.TestCase):
  
      def TestCorrectness(self):
          self.assertEqual(GeneratePrimeNumbers(20), [2, 3, 5, 7, 11, 13, 17, 19])
  
  
      def TestZero(self):
          self.assertEqual(GeneratePrimeNumbers(0), "Zero or One cannot be prime numbers.")
  
      def TestOne(self):
          self.assertEqual(GeneratePrimeNumbers(1), "Zero or One cannot be prime numbers.")
  
      def TestString(self):
          self.assertEqual(GeneratePrimeNumbers("String"), "Only integers are allowed.")
  
      def TestNegativeNumbers(self):
          self.assertEqual(GeneratePrimeNumbers(-1), "Not possible to generate prime numbers for integers less than 2.")
  
  
  if __name__ == "__main__":
         unittest.main()
  
  
         
  
new_contents: 
  import unittest
  from GeneratePrimeNumbers import GeneratePrimeNumbers
  
  
  class TestPrimeGenerator(unittest.TestCase):
  
      def TestCorrectness(self):
          #test whether the function generates correct prime numbers
          self.assertEqual(GeneratePrimeNumbers(20), [2, 3, 5, 7, 11, 13, 17, 19])
  
  
      def TestZero(self):
          self.assertEqual(GeneratePrimeNumbers(0), "Zero or One cannot be prime numbers.")
  
      def TestOne(self):
          self.assertEqual(GeneratePrimeNumbers(1), "Zero or One cannot be prime numbers.")
  
      def TestString(self):
          #makes sure that strings are not executed
          self.assertEqual(GeneratePrimeNumbers("String"), "Only integers are allowed.")
  
      def TestNegativeNumbers(self):
          #makes sure that only positive numbers are processed if the number is negative an error is displayed
          self.assertEqual(GeneratePrimeNumbers(-1), "Not possible to generate prime numbers for integers less than 2.")
  
  
  if __name__ == "__main__":
         unittest.main()
  
  
         
  
subject: Update TestPrimeNumbers.py