diff --git a/test_stack.c b/test_stack.c
index abd14c0..9f14a45 100644
--- a/test_stack.c
+++ b/test_stack.c
@@ -18,11 +18,65 @@ void test_createNode(void) {
   free(testNode);
 }
 
-void test_pushDataToStack(void) {}
+void test_pushDataToStack(void) {
 
-void test_deleteTopElement(void) {}
+  int testInt = 27;
 
-void test_returnData(void) {}
+  StackNode *testNode = push(NULL, &testInt);
+
+  TEST_ASSERT_NOT_NULL(testNode);
+  TEST_ASSERT_EQUAL_PTR(&testInt, testNode->data);
+  TEST_ASSERT_NULL(testNode->next);
+  TEST_ASSERT_NULL(testNode->prev);
+
+  free(testNode);
+}
+
+void test_deleteTopElement(void) {
+
+  int testInts[] = {10, 20, 30};
+  StackNode *stack = NULL;
+
+  for (int i = 0; i < 3; i++) {
+    stack = push(stack, &testInts[i]);
+  }
+
+  TEST_ASSERT_EQUAL_PTR(&testInts[2], top(stack));
+
+  stack = pop(stack);
+  TEST_ASSERT_EQUAL_PTR(&testInts[1], top(stack));
+
+  stack = pop(stack);
+  TEST_ASSERT_EQUAL_PTR(&testInts[0], top(stack));
+
+  stack = pop(stack);
+  TEST_ASSERT_NULL(stack);
+}
+
+void test_returnData(void) {
+
+  int testInts[] = {10, 20, 30};
+  StackNode *stack = NULL;
+
+  for (int i = 0; i < 3; i++) {
+    stack = push(stack, &testInts[i]);
+  }
+
+  TEST_ASSERT_EQUAL_PTR(&testInts[2], top(stack));
+
+  if (stack->next != NULL) {
+    TEST_ASSERT_EQUAL_PTR(&testInts[1], stack->next->data);
+    if (stack->next->next != NULL) {
+      TEST_ASSERT_EQUAL_PTR(&testInts[0], stack->next->next->data);
+    }
+  }
+
+  StackNode *last = stack;
+  while (last->next != NULL) {
+    last = last->next;
+  }
+  TEST_ASSERT_NULL(last->next);
+}
 
 void test_clearStack(void) {
   int testInts[] = {1, 2, 3, 4, 5};
@@ -51,7 +105,6 @@ int main(void) {
   RUN_TEST(test_deleteTopElement);
   RUN_TEST(test_returnData);
   RUN_TEST(test_clearStack);
-  RUN_TEST(test_clearStack);
 
   return UNITY_END();
 }