Add unit tests for authentication and webhook parsing

- Implement tests for basic and bearer authentication headers in `test_auth.py`.
- Create tests for the `EasybillWebhookParser` in `test_webhooks.py`, covering JSON and form-encoded payloads, as well as a generic parse and acknowledgement method.

generated/async/test/test_stocks.py

@@ -0,0 +1,70 @@
+# coding: utf-8
+
+"""
+    easybill REST API
+
+     The first version of the easybill REST API. [CHANGELOG](https://api.easybill.de/rest/v1/CHANGELOG.md)  ## Authentication  You can choose between two available methods: `Basic Auth` or `Bearer Token`.  In each HTTP request, one of the following HTTP headers is required:  ``` # Basic Auth Authorization: Basic base64_encode('<email>:<api_key>') # Bearer Token Authorization: Bearer <api_key> ```  ## Limitations  ### Request Limit  * PLUS: 10 requests per minute * BUSINESS: 60 requests per minute  If the limit is exceeded, you will receive the HTTP error: `429 Too Many Requests`  ### Result Limit  All result lists are limited to 100 by default. This limit can be increased by the query parameter `limit` to a maximum of 1000.  ## Query filter  Many list resources can be filtered. In `/documents` you can filter e.g. by number with `/documents?number=111028654`. If you want to filter multiple numbers, you can either enter them separated by commas `/documents?number=111028654,222006895` or as an array `/documents?number[]=111028654&number[]=222006895`.  **Warning**: The maximum size of an HTTP request line in bytes is 4094. If this limit is exceeded, you will receive the HTTP error: `414 Request-URI Too Large`  ### Escape commas in query  You can escape commans in query `name=Patrick\\, Peter` if you submit the header `X-Easybill-Escape: true` in your request.  ## Property login_id  This is the login of your admin or employee account.  ## Date and Date-Time format Please use the timezone `Europe/Berlin`. * **date** = *Y-m-d* = `2016-12-31` * **date-time** = *Y-m-d H:i:s* = `2016-12-31 03:13:37`  Date or datetime can be `null` because the attributes have been added later and the entry is older.
+
+    The version of the OpenAPI document: 1.96.0
+    Generated by OpenAPI Generator (https://openapi-generator.tech)
+
+    Do not edit the class manually.
+"""  # noqa: E501
+
+
+import unittest
+
+from easybill_generated_async.models.stocks import Stocks
+
+class TestStocks(unittest.TestCase):
+    """Stocks unit test stubs"""
+
+    def setUp(self):
+        pass
+
+    def tearDown(self):
+        pass
+
+    def make_instance(self, include_optional) -> Stocks:
+        """Test Stocks
+            include_optional is a boolean, when False only required
+            params are included, when True both required and
+            optional params are included """
+        # uncomment below to create an instance of `Stocks`
+        """
+        model = Stocks()
+        if include_optional:
+            return Stocks(
+                page = 1,
+                pages = 1,
+                limit = 100,
+                total = 20,
+                items = [
+                    easybill_generated_async.models.stock.Stock(
+                        id = 56, 
+                        note = 'Correction for stock count of the Entry from 11/01/2017', 
+                        stock_count = 666, 
+                        position_id = 56, 
+                        document_id = 56, 
+                        document_position_id = 56, 
+                        stored_at = '2017-04-11 13:00:00', 
+                        created_at = '2018-01-01 23:23:45', 
+                        updated_at = '2018-01-01 23:23:45', )
+                    ]
+            )
+        else:
+            return Stocks(
+                page = 1,
+                pages = 1,
+                limit = 100,
+                total = 20,
+        )
+        """
+
+    def testStocks(self):
+        """Test Stocks"""
+        # inst_req_only = self.make_instance(include_optional=False)
+        # inst_req_and_optional = self.make_instance(include_optional=True)
+
+if __name__ == '__main__':
+    unittest.main()