initial implementation for numbers.c with some testing in test_numbers.c

numbers.c currently uses the qsort() function from stdlib

test_numbers.c

@@ -0,0 +1,50 @@
+#include "unity.h"
+// #include "bintree.h"
+// #include "string.h"
+#include "numbers.h"
+#include "stdlib.h"
+
+void setUp(void)
+{
+    // set stuff up here
+}
+
+void tearDown(void)
+{
+    // set stuff up here
+}
+
+// getDuplicate on array without duplicats
+// expects 0/error
+void test_get_duplicate_error(void)
+{
+    unsigned int input[] = {1, 5, 9, 2, 4};
+    unsigned int len = sizeof(input) / sizeof(input[0]);
+
+    TEST_ASSERT_EQUAL_UINT(0, getDuplicate(input, len));
+}
+
+// this tries to brute force a triple
+void test_for_triple(void)
+{
+    // this test is less effective if srand is called inside createNumbers()
+    for (int i = 0; i < 100000; i++)
+    {
+        unsigned int *numbers = createNumbers(3);
+        if (numbers[0] == numbers[1] && numbers[1] == numbers[2])
+        {
+            // fail the test
+            TEST_ASSERT(0);
+        }
+        free(numbers);
+    }
+}
+
+int main(void)
+{
+    printf("============================\nNumbers tests\n============================\n");
+    UNITY_BEGIN();
+    RUN_TEST(test_get_duplicate_error);
+    RUN_TEST(test_for_triple);
+    return UNITY_END();
+}