From 0a37b5982afdf531406ac4a5111a85692d4e3e50 Mon Sep 17 00:00:00 2001
From: Murilo Pereira <murilo@murilopereira.com>
Date: Sun, 1 May 2011 02:04:16 -0300
Subject: [PATCH] Really, don't change the stack when calling stack#reverse.

---
 lib/stack.c       | 6 +++---
 test/stack_test.c | 8 +++++---
 2 files changed, 8 insertions(+), 6 deletions(-)

diff --git a/lib/stack.c b/lib/stack.c
index b74a3ce..0688b5f 100644
--- a/lib/stack.c
+++ b/lib/stack.c
@@ -97,12 +97,12 @@ struct stack *pop(struct stack **stack) {
 
 struct stack *reverse(struct stack *stack) {
   if (length(stack) > 1) {
-    struct stack *tmp_stack;
+    struct stack *tmp_stack, *iterator;
 
     allocate_stack(&tmp_stack);
     initialize_stack(tmp_stack);
-    while (!empty(stack)) {
-      push(&tmp_stack, pop((&stack))->card);
+    for (iterator = stack; iterator; iterator = iterator->next) {
+      push(&tmp_stack, iterator->card);
     }
     return(tmp_stack);
   } else {
diff --git a/test/stack_test.c b/test/stack_test.c
index 3d31ee4..d61d94f 100644
--- a/test/stack_test.c
+++ b/test/stack_test.c
@@ -276,7 +276,7 @@ void test_reverse_on_stack_with_more_than_one_element() {
 }
 
 void test_reverse_should_not_change_stack() {
-  struct stack *stack, *old_stack;
+  struct stack *stack, *old_stack, *old_stack_address;
   struct card *card[3];
 
   allocate_stack(&stack);
@@ -287,10 +287,12 @@ void test_reverse_should_not_change_stack() {
     set_card(card[i], TWO + i, DIAMONDS + i, EXPOSED, 0, 0);
     push(&stack, card[i]);
   }
-  old_stack = stack;
+  old_stack_address = stack;
+  old_stack = duplicate_stack(stack);
   reverse(stack);
 
-  assert(stack == old_stack);
+  assert(stack == old_stack_address);
+  assert(stacks_equal(stack, old_stack));
 
   free_stack(stack);
 }