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Black box tests for insertion procedure

insertion_procedure (int a[], int p [], int N)
{
    int i,j,k;
    for (i=0; i<=N; i++) p[i] = i;
    for (i=2; i<=N; i++)
    {
        k = p[i];
        j = 1;
        while (a[p[j-1]] > a[k]) {p[j] = p[j-1]; j--}
        p[j] = k;
    }
}

What would be some good test cases for this particular insert procedure?

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2 answers


If I read this function correctly, any input with this property a [0]> a [2] will be detected

First cycle through for (i=2; i<=N; i++)

Tracking variables in my head.



  • i = 2

  • k = p[i] == 2

  • j = 1

  • p[j-1] = p[0] == 0

  • Since the a[0] > a[2]

    while condition is true, soj-- == 0

  • The following evaulation while operation will do: - while (a[p[-1] > k)

    > SEGFAULT

This might be a good test :-)

It doesn't look like there is any useful input that would force this if the loop ran more than once without a segfault, so I would say there is a logic error in there.

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I would start with these

  • negative number in []. What should be the result?
  • negative number in p [].
  • negative number N.
  • empty array.
  • an empty array p.
  • N = 0

Looking at the implementation (I'm not programming in c), I suspect some of them will be AV.



In a nutshell, you should at least do a boundary analysis of your inputs and device to test each parameter with every value out of bounds, on bounds, and in.

Example
If you have 1 parameter and define boundaries 0 and 10, this should result in 6 test files. You should go to -1, 0, 1, 9, 10 and 11.

Further Study
As the number of parameters increases, it quickly becomes impossible to test combinations of everything . This is where testing all pairs comes in handy.

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