Added other tests

tests/08_arena_exception.c

@@ -0,0 +1,28 @@
+#define DEBUG
+#include <stdlib.h>
+#include <stdint.h>
+#include <stdio.h>
+#include "../include/mem.h"
+
+int main(void){
+    size_t nbytes = MEM_GB(1024);
+    Arena a;
+    TRY {
+        a = ARENA(0,nbytes); /* try 1GB */
+        if (!a.beg)
+            RAISE(OOM);
+        free(a.beg);
+    }
+    EXCEPT(OOM) {
+        /* handle memory failure gracefully */
+        fprintf(stderr, "Caught: %s\n", OOM.reason);
+        return EXIT_SUCCESS; /* requested behavior */
+    }
+    FINALLY {
+        /* cleanup if needed, runs always */
+        if (a.beg) free(a.beg);
+    }
+    END_TRY;
+
+    return EXIT_FAILURE; /* shouldn't reach here for this example */
+  }