/**
 * utest_swap.c - unit tests for the swap procedure.
 */

#include <stdio.h>
#include <stdlib.h>
#include "array_utils.h"


// +-----------+------------------------------------------------------
// | Constants |
// +-----------+

/** The size of the array we use for testing. */
#define SIZE 32

/** The starting values of that array. */
#define START -10


// +-----------+------------------------------------------------------
// | Variables |
// +-----------+

/**
 * A count of errors.
 */
static int errors = 0;


// +---------+--------------------------------------------------------
// | Helpers |
// +---------+

/**
 * A quick test of swap.
 */
static void
test_swap (int a[], int i, int j)
{
  int x = a[i];
  int y = a[j];
  swap (a, i, j);
  if (a[i] != y)
    {
      printf ("After swapping positions %d and %d, "
              " expected %d at %d but found %d.\n",
              i, j, y, i, a[i]);
      ++errors;
    }
  if (a[j] != x)
    {
      printf ("After swapping positions %d and %d, "
              " expected %d at %d but found %d.\n",
              i, j, x, j, a[j]);
      ++errors;
    }
} // test_swap

// +------+-----------------------------------------------------------
// | Main |
// +------+

int
main ()
{
  int values[SIZE];
  int i, j;

  // Fill in the array
  for (i = 0; i < SIZE; i++)
    values[i] = i + START;

  // Try swapping every pair of positions
  for (i = 0; i < SIZE; i++)
    {
      for (j = 0; j < SIZE; j++)
        {
          // We swap the values and then swap them back again.
          test_swap (values, i, j);
          test_swap (values, i, j);
        } // for j
    } // for i

  // And we're done
  if (errors)
    {
      printf ("%d errors encountered.\n", errors);
      return EXIT_FAILURE;
    }
  else
    {
      return EXIT_SUCCESS;
    }
} // main