Fix SKU field retrieval in Item.all() and clean up test files

The SKU field was not being properly returned when using Item.all() due to
the field not being explicitly requested in the query. This commit:

1. Adds test_sku_in_all() to tests/integration/test_item.py to verify SKU
   field retrieval
2. Removes trailing slashes from API URLs in get_single_object method
3. Cleans up test files by:
   - Removing sleep statements and debug prints from test_account.py
   - Using proper mocking in unit tests to avoid session dependency
   - Making test names and assertions more descriptive

The changes ensure that SKU values are correctly returned when querying
items through the all() method, while also improving the overall test
suite maintainability.

Testing:
- Added new integration test verifying SKU field retrieval
- All existing Item and Account tests pass
- Unit tests properly mock session dependencies

Author: laf-rge

tests/unit/test_client.py

@@ -262,7 +262,7 @@ def test_make_request_file_closed(self, process_request):
 class MockResponse(object):
     @property
     def text(self):
-        return "oauth_token_secret=secretvalue&oauth_callback_confirmed=true&oauth_token=tokenvalue"
+        return '{"QueryResponse": {"Department": []}}'
 
     @property
     def status_code(self):
@@ -273,10 +273,8 @@ def status_code(self):
         return httplib.OK
 
     def json(self):
-        return "{}"
+        return json.loads(self.text)
 
-    def content(self):
-        return ''
 
 class MockResponseJson:
     def __init__(self, json_data=None, status_code=200):
@@ -325,5 +323,8 @@ def get_session(self):
 
 
 class MockSession(object):
-    def request(self, request_type, url, no_idea, company_id, **kwargs):
+    def __init__(self):
+        self.access_token = "test_access_token"
+
+    def request(self, request_type, url, headers=None, params=None, data=None, **kwargs):
         return MockResponse()

tests/unit/test_mixins.py

@@ -133,10 +133,12 @@ def test_to_dict(self):
 
 
 class ListMixinTest(QuickbooksUnitTestCase):
-    @patch('quickbooks.mixins.ListMixin.where')
-    def test_all(self, where):
+    @patch('quickbooks.mixins.ListMixin.query')
+    def test_all(self, query):
+        from mock import ANY
+        query.return_value = []
         Department.all()
-        where.assert_called_once_with('', order_by='', max_results=100, start_position='', qb=None)
+        query.assert_called_once_with("SELECT * FROM Department MAXRESULTS 100", qb=ANY)
 
     def test_all_with_qb(self):
         self.qb_client.session = MockSession()  # Add a mock session