text: import unittest
  import calc
  
  class TestCalc(unittest.TestCase):
      
      def test_add(self):
          
          self.assertEqual(calc.add(10,2),12)
          self.assertEqual(calc.add(-1,2),1)
          self.assertEqual(calc.add(-10,-2),-12)
          self.assertEqual(calc.add(19,0),19)   
           
      def test_sub(self):
          
          self.assertEqual(calc.subtract(10,2),8)
          self.assertEqual(calc.subtract(-1,2),-3)
          self.assertEqual(calc.subtract(-10,-2),-8)
          self.assertEqual(calc.subtract(19,0),19)  
            
      def test_multiply(self):
          
          self.assertEqual(calc.multiply(10,2),20)
          self.assertEqual(calc.multiply(-1,2),-2)
          self.assertEqual(calc.multiply(-10,-2),20)
          self.assertEqual(calc.multiply(19,0),0)    
          
      def test_divide(self):
          
          self.assertEqual(calc.divide(10,2),5)
          self.assertEqual(calc.divide(-1,2),-0.5)
          self.assertEqual(calc.divide(-10,-2),5)
          self.assertEqual(calc.divide(19,19),1)
          
          with self.assertRaises(ValueError):
              calc.divide(10,0)
              
          
  if __name__ == "__main__":
      
      unittest.main()