Tests for queue and stack updated (#163)

pydatastructs/miscellaneous_data_structures/stack.py

@@ -150,10 +150,6 @@ def is_empty(self):
 
     @property
     def peek(self):
-        return self.top.data
-
-    @property
-    def top(self):
         return self.stack.head
 
     @property
@@ -164,4 +160,9 @@ def __len__(self):
         return self.stack.size
 
     def __str__(self):
-        return str(self.stack)
+        elements = []
+        current_node = self.peek
+        while current_node is not None:
+            elements.append(current_node.data)
+            current_node = current_node.next
+        return str(elements[::-1])

pydatastructs/miscellaneous_data_structures/tests/test_queue.py

@@ -1,8 +1,20 @@
 from pydatastructs.miscellaneous_data_structures import Queue
+from pydatastructs.miscellaneous_data_structures.queue import ArrayQueue, LinkedListQueue
 from pydatastructs.utils.raises_util import raises
+from pydatastructs.utils.misc_util import _check_type
 
 def test_Queue():
+    q = Queue(implementation='array')
+    q1 = Queue()
+    assert _check_type(q, ArrayQueue) is True
+    assert _check_type(q1, ArrayQueue) is True
+    q2 = Queue(implementation='linked_list')
+    assert _check_type(q2, LinkedListQueue) is True
+    assert raises(NotImplementedError, lambda: Queue(implementation=''))
 
+def test_ArrayQueue():
+    q1 = Queue()
+    raises(IndexError, lambda: q1.popleft())
     q1 = Queue(implementation='array', items=[0])
     q1.append(1)
     q1.append(2)
@@ -16,9 +28,7 @@ def test_Queue():
     assert q1.popleft() == 3
     assert len(q1) == 0
 
-    q1 = Queue()
-    raises(IndexError, lambda: q1.popleft())
-
+def test_LinkedListQueue():
     q1 = Queue(implementation='linked_list')
     q1.append(1)
     assert raises(TypeError, lambda: Queue(implementation='linked_list', items={0, 1}))

pydatastructs/miscellaneous_data_structures/tests/test_stack.py

@@ -1,10 +1,19 @@
 from pydatastructs.miscellaneous_data_structures import Stack
-from pydatastructs.linear_data_structures import OneDimensionalArray
+from pydatastructs.miscellaneous_data_structures.stack import ArrayStack, LinkedListStack
 from pydatastructs.utils.raises_util import raises
+from pydatastructs.utils.misc_util import _check_type
 
 def test_Stack():
+    s = Stack(implementation='array')
+    s1 = Stack()
+    assert _check_type(s, ArrayStack) is True
+    assert _check_type(s1, ArrayStack) is True
+    s2 = Stack(implementation='linked_list')
+    assert _check_type(s2, LinkedListStack) is True
+    assert raises(NotImplementedError, lambda: Stack(implementation=''))
 
-    s = Stack()
+def test_ArrayStack():
+    s = Stack(implementation='array')
     s.push(1)
     s.push(2)
     s.push(3)
@@ -18,30 +27,28 @@ def test_Stack():
     _s = Stack(items=[1, 2, 3])
     assert str(_s) == '[1, 2, 3]'
     assert len(_s) == 3
-    assert raises(NotImplementedError, lambda: Stack(implementation=''))
 
+def test_LinkedListStack():
     s = Stack(implementation='linked_list')
     s.push(1)
     s.push(2)
     s.push(3)
-    assert s.peek == 3
-    assert str(s) == '[3, 2, 1]'
+    assert s.peek.data == 3
+    assert str(s) == '[1, 2, 3]'
     assert s.pop().data == 3
     assert s.pop().data == 2
     assert s.pop().data == 1
     assert s.is_empty is True
     assert raises(IndexError, lambda : s.pop())
+    assert str(s) == '[]'
     _s = Stack(implementation='linked_list',items=[1, 2, 3])
-    assert str(_s) == '[3, 2, 1]'
+    assert str(_s) == '[1, 2, 3]'
     assert len(_s) == 3
 
     s = Stack(implementation='linked_list',items=['a',None,type,{}])
     assert len(s) == 4
     assert s.size == 4
 
-    top = s.top
-    assert top.data == s.pop().data
-
     peek = s.peek
-    assert peek == s.pop().data
+    assert peek.data == s.pop().data
     assert raises(TypeError, lambda: Stack(implementation='linked_list', items={0, 1}))