diff --git a/lib/card.c b/lib/card.c
index 73c02ec..e44b39d 100644
--- a/lib/card.c
+++ b/lib/card.c
@@ -25,6 +25,20 @@ void initialize_card(struct card *card) {
   return;
 }
 
+struct card *duplicate_card(struct card *card) {
+  struct card *new_card;
+
+  allocate_card(&new_card);
+  set_card(new_card,
+           card->value,
+           card->suit,
+           card->face,
+           card->frame->start_y,
+           card->frame->start_x);
+
+  return(new_card);
+}
+
 void free_card(struct card *card) {
   if (card) {
     free_frame(card->frame);
diff --git a/lib/card.h b/lib/card.h
index 766e3ad..996a5cf 100644
--- a/lib/card.h
+++ b/lib/card.h
@@ -45,6 +45,7 @@ extern const char *program_name;
 
 void allocate_card(struct card **);
 void initialize_card(struct card *);
+struct card *duplicate_card(struct card *);
 void free_card(struct card *);
 void set_card(struct card *, enum value, enum suit, enum face, int, int);
 void expose_card(struct card *);
diff --git a/lib/frame.c b/lib/frame.c
index 06dbde2..a1ea4fb 100644
--- a/lib/frame.c
+++ b/lib/frame.c
@@ -22,6 +22,15 @@ void initialize_frame(struct frame *frame) {
   return;
 }
 
+struct frame *duplicate_frame(struct frame *frame) {
+  struct frame *new_frame;
+
+  allocate_frame(&new_frame);
+  set_frame(new_frame, frame->start_y, frame->start_x);
+
+  return(new_frame);
+}
+
 void free_frame(struct frame *frame) {
   if (frame) {
     delwin(frame->shape);
diff --git a/lib/frame.h b/lib/frame.h
index 04baebb..1b4ad04 100644
--- a/lib/frame.h
+++ b/lib/frame.h
@@ -16,6 +16,7 @@ extern const char *program_name;
 
 void allocate_frame(struct frame **);
 void initialize_frame(struct frame *);
+struct frame *duplicate_frame(struct frame *);
 void free_frame(struct frame *);
 void set_frame(struct frame *, int, int);
 
diff --git a/lib/stack.c b/lib/stack.c
index 0688b5f..41b1ab9 100644
--- a/lib/stack.c
+++ b/lib/stack.c
@@ -24,6 +24,25 @@ void initialize_stack(struct stack *stack) {
   return;
 }
 
+struct stack *duplicate_stack(struct stack *stack) {
+  struct stack *iterator = stack;
+  struct stack *tmp_stack, *new_stack;
+
+  allocate_stack(&new_stack);
+  allocate_stack(&tmp_stack);
+  initialize_stack(new_stack);
+  initialize_stack(tmp_stack);
+  for (iterator = stack; iterator; iterator = iterator->next) {
+    push(&tmp_stack, duplicate_card(iterator->card));
+  }
+  while (!empty(tmp_stack)) {
+    push(&new_stack, (pop(&tmp_stack))->card);
+  }
+  free_stack(tmp_stack);
+
+  return(new_stack);
+}
+
 void free_stack(struct stack *stack) {
   struct stack *tmp_stack;
 
diff --git a/lib/stack.h b/lib/stack.h
index 89372f4..fe5b655 100644
--- a/lib/stack.h
+++ b/lib/stack.h
@@ -12,6 +12,7 @@ extern const char *program_name;
 
 void allocate_stack(struct stack **);
 void initialize_stack(struct stack *);
+struct stack *duplicate_stack(struct stack *);
 void free_stack(struct stack *);
 bool empty(struct stack *);
 int length(struct stack *);
diff --git a/test/card_test.c b/test/card_test.c
index 41d29e7..38235d7 100644
--- a/test/card_test.c
+++ b/test/card_test.c
@@ -16,6 +16,20 @@ void test_initialize_card() {
   return;
 }
 
+void test_duplicate_card() {
+  struct card *card_0, *card_1;
+  const int start_y = 5, start_x = 10;
+
+  allocate_card(&card_0);
+  set_card(card_0, ACE, SPADES, EXPOSED, start_y, start_x);
+  card_1 = duplicate_card(card_0);
+
+  assert(card_0 != card_1);
+  assert(cards_equal(card_0, card_1));
+
+  return;
+}
+
 void test_set_card() {
   struct card *card;
   int start_y = 5;
@@ -66,6 +80,7 @@ void test_cover_card() {
 
 void test_card() {
   test_initialize_card();
+  test_duplicate_card();
   test_set_card();
   test_expose_card();
   test_cover_card();
diff --git a/test/frame_test.c b/test/frame_test.c
index ec2d0ed..53b9b6b 100644
--- a/test/frame_test.c
+++ b/test/frame_test.c
@@ -16,6 +16,20 @@ void test_initialize_frame() {
   return;
 }
 
+void test_duplicate_frame() {
+  struct frame *frame_0, *frame_1;
+  const int start_y = 5, start_x = 10;
+
+  allocate_frame(&frame_0);
+  set_frame(frame_0, start_y, start_x);
+  frame_1 = duplicate_frame(frame_0);
+
+  assert(frame_0 != frame_1);
+  assert(frames_equal(frame_0, frame_1));
+
+  return;
+}
+
 void test_set_frame() {
   struct frame *frame;
   int start_y = 5;
@@ -35,6 +49,7 @@ void test_set_frame() {
 
 void test_frame() {
   test_initialize_frame();
+  test_duplicate_frame();
   test_set_frame();
 
   return;
diff --git a/test/stack_test.c b/test/stack_test.c
index d61d94f..a8eb6d6 100644
--- a/test/stack_test.c
+++ b/test/stack_test.c
@@ -16,6 +16,26 @@ void test_initialize_stack() {
   return;
 }
 
+void test_duplicate_stack() {
+  struct stack *stack_0, *stack_1;
+  struct card *card[5];
+  const int start_y = 5, start_x = 10;
+
+  allocate_stack(&stack_0);
+  initialize_stack(stack_0);
+  for (int i = 0; i < 5; i++) {
+    allocate_card(&card[i]);
+    set_card(card[i], i, SPADES, EXPOSED, start_y, start_x);
+    push(&stack_0, card[i]);
+  }
+  stack_1 = duplicate_stack(stack_0);
+
+  assert(stack_0 != stack_1);
+  assert(stacks_equal(stack_0, stack_1));
+
+  return;
+}
+
 void test_empty_on_empty_stack() {
   struct stack *stack;
 
@@ -300,6 +320,8 @@ void test_reverse_should_not_change_stack() {
 void test_stack() {
   test_initialize_stack();
 
+  test_duplicate_stack();
+
   test_empty_on_empty_stack();
   test_empty_on_non_empty_stack();
 
diff --git a/test/test_helper.c b/test/test_helper.c
index 71960bc..62a22dc 100644
--- a/test/test_helper.c
+++ b/test/test_helper.c
@@ -34,45 +34,3 @@ bool stacks_equal(struct stack *stack_0, struct stack *stack_1) {
     return(true);
   }
 }
-
-struct frame *duplicate_frame(struct frame *frame) {
-  struct frame *new_frame;
-
-  allocate_frame(&new_frame);
-  set_frame(new_frame, frame->start_y, frame->start_x);
-
-  return(new_frame);
-}
-
-struct card *duplicate_card(struct card *card) {
-  struct card *new_card;
-
-  allocate_card(&new_card);
-  set_card(new_card,
-           card->value,
-           card->suit,
-           card->face,
-           card->frame->start_y,
-           card->frame->start_x);
-
-  return(new_card);
-}
-
-struct stack *duplicate_stack(struct stack *stack) {
-  struct stack *iterator = stack;
-  struct stack *tmp_stack, *new_stack;
-
-  allocate_stack(&new_stack);
-  allocate_stack(&tmp_stack);
-  initialize_stack(new_stack);
-  initialize_stack(tmp_stack);
-  for (iterator = stack; iterator; iterator = iterator->next) {
-    push(&tmp_stack, duplicate_card(iterator->card));
-  }
-  while (!empty(tmp_stack)) {
-    push(&new_stack, (pop(&tmp_stack))->card);
-  }
-  free_stack(tmp_stack);
-
-  return(new_stack);
-}
diff --git a/test/test_helper.h b/test/test_helper.h
index ca83500..354a56f 100644
--- a/test/test_helper.h
+++ b/test/test_helper.h
@@ -9,8 +9,5 @@
 bool frames_equal(struct frame *, struct frame *);
 bool cards_equal(struct card *, struct card *);
 bool stacks_equal(struct stack *, struct stack *);
-struct frame *duplicate_frame(struct frame *);
-struct card *duplicate_card(struct card *);
-struct stack *duplicate_stack(struct stack *);
 
 #endif
diff --git a/test/test_helper_test.c b/test/test_helper_test.c
index 085f235..a3a0493 100644
--- a/test/test_helper_test.c
+++ b/test/test_helper_test.c
@@ -145,55 +145,6 @@ void test_stacks_equal_with_two_stack_pointers_to_the_same_address() {
   return;
 }
 
-void test_duplicate_frame() {
-  struct frame *frame_0, *frame_1;
-  const int start_y = 5, start_x = 10;
-
-  allocate_frame(&frame_0);
-  set_frame(frame_0, start_y, start_x);
-  frame_1 = duplicate_frame(frame_0);
-
-  assert(frame_0 != frame_1);
-  assert(frames_equal(frame_0, frame_1));
-
-  return;
-}
-
-void test_duplicate_card() {
-  struct card *card_0, *card_1;
-  const int start_y = 5, start_x = 10;
-
-  allocate_card(&card_0);
-  set_card(card_0, ACE, SPADES, EXPOSED, start_y, start_x);
-  card_1 = duplicate_card(card_0);
-
-  assert(card_0 != card_1);
-  assert(cards_equal(card_0, card_1));
-
-  return;
-}
-
-void test_duplicate_stack() {
-  struct stack *stack_0, *stack_1;
-  struct card *card[5];
-  const int start_y = 5, start_x = 10;
-
-  allocate_stack(&stack_0);
-  initialize_stack(stack_0);
-  for (int i = 0; i < 5; i++) {
-    allocate_card(&card[i]);
-    set_card(card[i], i, SPADES, EXPOSED, start_y, start_x);
-    push(&stack_0, card[i]);
-  }
-  stack_1 = duplicate_stack(stack_0);
-
-  assert(stack_0 != stack_1);
-  assert(stacks_equal(stack_0, stack_1));
-
-  return;
-}
-
-
 void test_test_helper() {
   test_frames_equal_with_two_nulls();
   test_frames_equal_with_one_null();
@@ -210,9 +161,5 @@ void test_test_helper() {
   test_stacks_equal_with_two_different_stacks();
   test_stacks_equal_with_two_stack_pointers_to_the_same_address();
 
-  test_duplicate_frame();
-  test_duplicate_card();
-  test_duplicate_stack();
-
   return;
 }