Unit Testing

• Runtime examination of “small” unit of a system code
  • typically: function, method, class
• Low level access to unit under test (UUT)
  • typically: procedure call
• Generally performed as part of the implementation of the unit
  • essential in TDD approaches

A Junit Test case

/** Test of setName() method, of class Value */
 @Test
 public void createAndSetName()
 {
    Value v1 = new Value( );
    v1.setName( "Y" );
    String expected = "Y";
    String actual = v1.getName( );
    Assert.assertEquals( expected, actual );
 }

Assertion Methods

• Boolean conditions are true or false
  • assertTrue(condition)
  • assertFalse(condition)
• Objects are null or non-null
  • assertNull(object)
  • assertNotNull(object)
• Objects are identical (i.e. two references to the same object), or not identical.
  • assertSame(expected, actual)
    • true if: expected == actual
  • assertNotSame(expected, actual)
• “Equality” of objects:
  • assertEquals(expected, actual)
    • Valid if: expected.equals( actual )
• “Equality” of arrays:
  • assertArrayEquals(expected, actual)
    • Parameters are either arrays of primitive types, or Object[].
• Unconditional failure assertion
  • fail() - always results in a fail verdict

A PyUnit Testcase

import unittest # test framework module import
from valueMod import Value # unit under test import
# test case definition
class MyTestCase(unittest.TestCase):
 # test method name start with “test”
    def test_createAndSetName(self):
    v1 = Value()
    print(v1.getName())
    v1.setName("Y")
    expected = "Y"
    self.assertEqual(expected, v1.getName())
# test runner invocation
if __name__ == '__main__':
 unittest.main()