test case to make sure realloc() can shrink buffers properly

test/malloc/realloc-can-shrink.c

@@ -0,0 +1,17 @@
+/* make sure that realloc() can properly shrink buffers */
+
+#include <stdlib.h>
+
+#define LARGE_BUFFER (1 << 20) /* idea is to span a lot of pages */
+
+int main()
+{
+	int count = 20;
+	char *ptr = NULL;
+	while (count--) {
+		ptr = realloc(ptr, LARGE_BUFFER);
+		ptr = realloc(ptr, 1);
+	}
+	free(ptr);
+	return 0;
+}