Question

Describe the following:

a. Test case

b. Backtracking c. Predicate

d. Path predicate

Answer 1

a. Test case

A TEST CASE is a set of conditions or variables under which a tester will determine whether a system under test satisfies requirements or works correctly.

The process of developing test cases can also help find problems in the requirements or design of an application.

Writing Good Test Cases

• As far as possible, write test cases in such a way that you test only one thing at a time. Do not overlap or complicate test cases. Attempt to make your test cases ‘atomic’.
• Ensure that all positive scenarios AND negative scenarios are covered.
• Language:
  • Write in simple and easy-to-understand language.
  • Use active voice instead of passive voice: Do this, do that.
  • Use exact and consistent names (of forms, fields, etc).
• Characteristics of a good test case:
  • Accurate: Exacts the purpose.
  • Economical: No unnecessary steps or words.
  • Traceable: Capable of being traced to requirements.
  • Repeatable: Can be used to perform the test over and over.
  • Reusable: Can be reused if necessary

Backtracking is a general algorithm for finding all (or some) solutions to some computational problems, notably constraint satisfaction problems, that incrementally builds candidates to the solutions, and abandons a candidate ("backtracks") as soon as it determines that the candidate cannot possibly be completed to a valid solution

Predicate:
The logical function evaluated at a decision is called predicate
The direction taken at a decision depends on the value of decision variable
Some examples are: A>0, x + y >= 90

Path Predicate:
A predicate associated with a path is called path predicate
Example: "X is greater than zero" is true
AND
"X + Y >=90" is false
AND
"W is either negative or equal to 10" is true