testing-testing/labTesting.md

Testing and Unit Testing

Objectives

Throughout this exercise the students will practice:

• Testing various versions of a program to validate their operation
• Unit Testing

Concepts

As you have learned in previous labs, getting a program to compile is only a minor part of programming. It is super important to test functions in order to validate that they produce the correct results.

Exercise 1

This exercise is an adaptation of [1]. You are provided with a program that implements several versions of five simple functions, e.g. rock-paper-scisors, sorting 3 numbers. By testing the versions, you and your partner will determine which of the versions is correctly implemented.

This exercise requires NO programming, just testing.

The functions implemented in the program are:

• 3 Sorts: a program that receives three strings and sorts them in lexicographical order. For example, given jirafa, zorra, and coqui. Will sort them as: coqui, jirafa, and zorra.

• Dice: when the user presses the Roll them button, the program will generate two random numbers between 1 and 6. The sum of the random numbers is reported.

• Rock, Papers, Scissors: The user enters the play for the two players ( ‘R’ for Rock, ‘P’ for Paper and ’S’ for Scissors) and specifies the number of games needed to win the tournament. The program then reports who won and the score. The program reports if a player wins the tournament.

• Check Writer: The user enters a number between 0 and 999,999,999 (inclusive). The program’s output is a long string version of the number. For example, if the user inputs ‘654123’ the program will output ‘six hundred fifty four thousand one hundred twenty three’.

• Zulu time: given the time in zulu time (Greenwich Mean Time) and the military zone that the user whishes to know, the program outputs the time at that zone. The format for the input is #### in 23 hour format, e.g. 2212. The list of valid military zones is given in http://en.wikipedia.org/wiki/List_of_military_time_zones. Examples of correct output:

  • Given 1230 and zone A, the output would be 1330
  • Given 1230 and zone N, the output would be 1130

Step 1: Download the program from $XYZ$.

Step 2: Run the program. For each of the functions, test all the versions and determine which is the valid one. Report which is the correct version in every method. Also, explain the tests that you performed that allowed you to determine that the other versions are incorrect.

Exercise 2

Running tests “by hand” each time that you run a program gets tiresome very quickly. You and your partner have done it for a few simple functions. Imagine doing the same for full-blown program!, such as a browser or word processor.

Unit tests help programmers produce valid code and ease the process of debugging while avoiding the tedious task of entering tests by hand on each execution.

Step 1: Download the proyect from $XYZ$. The proyect contains only one source code file main.cpp. This file contains four functions whose results are only partially correct. Your task is to write unit tests for each them to identify their wrong results.

A unit test function test_fact() is provided for the function fact. If you invoke this function from main and compile and run the program. You will get the following message:

Assertion failed: (fact(2) == 2), function test_fact, file ../UnitTests/main.cpp, line 69.

This would be enough for us to claim that function fact is not correctly implemented. Comment the invocation of test_fact() from main.

Step 2: Write unit tests for the rest of the functions. Remember that you must call each of the unit test functions from the main for them to run. Copy each of the functions in the provided sheet.

References

[1] http://nifty.stanford.edu/2005/TestMe/