Port average to unit test

test/average.c

@@ -18,16 +18,18 @@
  * SPDX-License-Identifier: GPL-3.0-or-later
  */
 
+#include <math.h>
+#include <stdbool.h>
 #include <stdio.h>
 #include <stdlib.h>
 
-#include "array.h"
+#include <array.h>
 
 #define INT_TO_PTR(x) ((void *) (size_t) (x))
 #define PTR_TO_INT(x) ((int) (size_t) (x))
 
 static double
-total_val (const Array *array,
+get_total (const Array *array,
            ValueFunc    func)
 {
     double total = 0;
@@ -40,10 +42,10 @@ total_val (const Array *array,
 }
 
 static double
-average_val (const Array *array,
+get_average (const Array *array,
              ValueFunc    func)
 {
-    return total_val (array, func) / array_get_length (array);
+    return get_total (array, func) / array_get_length (array);
 }
 
 static double
@@ -52,20 +54,6 @@ array_to_int (const void *data)
     return (double) PTR_TO_INT (data);
 }
 
-static void
-print_array (Array *array)
-{
-    size_t length = array_get_length (array);
-    printf ("Array at %p is of length %zu\n", array, length);
-    printf ("Array has capacity %zu\n", array_get_capacity (array));
-
-    double total = total_val (array, array_to_int);
-    double average = average_val (array, array_to_int);
-    
-    printf ("Array total is %lf\n", total);
-    printf ("Array average is %lf\n", average);
-}
-
 static Array *
 create_test_array (size_t start,
                    size_t end)
@@ -78,11 +66,40 @@ create_test_array (size_t start,
     return array;
 }
 
+static bool
+is_close (double a,
+          double b)
+{
+    return fabs (a - b) <= (1e-8 + 1e-5 * b); // Values from numpy
+}
+
 int
 main (void)
 {
-    Array *array = create_test_array (0, 100);
-    print_array (array);
+    int start = 1;
+    int end = 100;
+
+    Array *array = create_test_array (start, end);
+
+    int n = end - start;
+    double expected_total = (n * (n+1)) / 2; // Only valid if starting from 1
+    double expected_average = expected_total / n;
+
+    double total = get_total (array, array_to_int);
+    if (!is_close (total, expected_total))
+    {
+        fprintf (stderr, "Expected total %lf, value returned was %lf\n",
+                 expected_total, total);
+        return EXIT_FAILURE;
+    }
+
+    double average = get_average (array, array_to_int);
+    if (!is_close (average, expected_average))
+    {
+        fprintf (stderr, "Expected average %lf, value returned was %lf\n",
+                 expected_average, average);
+        return EXIT_FAILURE;
+    }
 
     return EXIT_SUCCESS;
 }

test/meson.build

 executable('testarray', 'testarray.c', link_with: lib, include_directories: lib_inc)
-executable('average', 'average.c', link_with: lib, include_directories: lib_inc)
+avg = executable('average', 'average.c', link_with: lib, include_directories: lib_inc)
 executable('range', 'range.c', link_with: lib, include_directories: lib_inc)
+
+test('average', avg)
\ No newline at end of file