diff --git a/makefile b/makefile
index 84878ed..0b03bab 100644
--- a/makefile
+++ b/makefile
@@ -49,7 +49,7 @@ stackTests: stack.o stackTests.c $(unityfolder)/unity.c
 # Clean
 # --------------------------
 clean:
-ifeq ($(OS),Windows_NT)
+ifeq ($(OS),!Windows_NT)
 	del /f *.o doble *.exe
 else
 	rm -f *.o doble *runNumbersTests
diff --git a/stack.c b/stack.c
index c78727b..d6735c9 100644
--- a/stack.c
+++ b/stack.c
@@ -20,17 +20,28 @@ StackNode *push(StackNode *stack, void *data)
 // freed by caller.)
 StackNode *pop(StackNode *stack)
 {
-
+    if(stack == NULL)
+        return NULL;
+    StackNode *next = stack->next;
+    free(stack);
+    return next;
 }
 
 // Returns the data of the top element.
 void *top(StackNode *stack)
 {
-
+    if(stack == NULL)
+        return NULL;
+    return stack->data;
 }
 
 // Clears stack and releases all memory.
 void clearStack(StackNode *stack)
 {
-
-}
\ No newline at end of file
+    while(stack != NULL)
+    {
+        StackNode *next = stack->next;
+        free(stack);
+        stack = next;
+    }
+}
diff --git a/stackTests.c b/stackTests.c
index 55dcedd..a70ff14 100644
--- a/stackTests.c
+++ b/stackTests.c
@@ -9,34 +9,20 @@ void tearDown(void){}
 
 void test_push_created_new_stacknode(void)
 {
-    StackNode test = {111,NULL};
-    int testdata = 222;
-    void *data =&testdata;
+    int testdata1 = 111;
+    StackNode test = {&testdata1,NULL};
+    int testdata2 = 222;
 
-    StackNode test1 = push(&test,data);
-    unsigned int n = 50;
-    unsigned int* arr = createNumbers(n);
-
-    TEST_ASSERT_NOT_NULL(arr);
-
-    // Ein paar Werte prüfen (dürfen alles sein, nur kein Segfault)
-    for (unsigned int i = 0; i < n; i++)
-        TEST_ASSERT_TRUE(arr[i] >= 0);
-
-    free(arr);
+    StackNode *test1 = push(&test,&testdata2);
+    TEST_ASSERT_NOT_NULL(test1);
+    TEST_ASSERT_EQUAL_PTR(&testdata2,test1->data);
+    TEST_ASSERT_EQUAL_PTR(&test,test1->next);
 }
 
-
-
-
-
 int main(void)
 {
     UNITY_BEGIN();
 
-    RUN_TEST(test_createNumbers_returns_valid_array);
-    RUN_TEST(test_createNumbers_contains_exactly_one_duplicate);
-    RUN_TEST(test_getDuplicated_finds_correct_duplicate);
-
+    RUN_TEST(test_push_created_new_stacknode);
     return UNITY_END();
 }
\ No newline at end of file