Clean-up and Testing and Debugging

• You frequently see

  • 
      bool badData;
    
      ...
    
      badData = (0.0 == height); 

  • This is equivalent to

  •   bool badData;
    
      if (0.0 == height) {
          badData = true;
      } else {
          badData = false;
      } 

  • Due to operator precedence, badData = 0.0== height; works as well
• Short circuit evaluation
  • In a complex boolean expression, it is sometimes not necessary to evaluate the entire expression to find the final value.
    • true or anything = true
    • false and anything = false
  • so in the expression x < 3 and ... if x is not less than 3, the expression will be false.
  • in the expression x < 3 or ... if x is less than 3, the expression will be true.
  • In such cases, evaluation will stop as soon as the value of the expression can be determined.
  • This becomes important later when we use arrays and linked lists.
  • So REMEMBER the concept.
• Testing
  • If our program has branches, we need to make sure that we evaluate each of the paths through our program.
  • For the programs we are writing now, this is easier
  • For later program, this becomes more difficult or even impossible.
  • This is called code coverage or white box testing because we look at the code to decide what to test.
  • In data coverage or black box testing we do not look at the code but consider the classes of data.
  • Both of these are very difficult if not impossible, so a mixture is used.
    • Look at the code to see what decisions are made
    • Use this to break the input data into multiple classes
    • Develop test data for each class, along with border data.
  • A Test Plan is a document that specifies how a program will be tested.
  • For your current program my test plan might include

    Case	Input Values	Expected Output	Observed Output
    Low Tokens	-4	Error: tokens per player is -4, which is less than 1.
    1 ≤ Tokens ≤ 100	1	Check against expected output
    1 ≤ Tokens ≤ 100	50	Check against expected output
    1 ≤ Tokens ≤ 100	100	Check against expected output
    High Tokens	101	Error: tokens per player is 101, which is greater than 100.
    High bid for player 1	21, assume tokens = 20	Error: player 1 contributed 21 tokens , which is more than the maximum 20.
    Low bid for player 1	-2, assume tokens = 20	Error: player 1 contributed -2 tokens , which is negative.
    Good bid for player 1	0, assume tokens = 100	Check final output against test cases.
    Good bid for player 1	10, assume tokens = 100	Check final output against test cases.
    Good bid for player 1	20, assume tokens = 100	Check final output against test cases.

  • In addition to the table I would have the following scenarios
    • Case 1:
      • Input: 100, 10, 20, 0, 1.1
      • Output: 101, 91, 111, C wins with 111
    • Case 2:
      • Input: 100, 100, 20, 0, 1.1
      • Output: 44, 134, 144, C wins with 144
    • ...
    • I would make sure that any valid case in the table above was listed.
  • Note, this is a black box test, based on the data.
  • You should read chapter 5.