From 6fae6dae058bdc234f65d31919f148502df06a67 Mon Sep 17 00:00:00 2001
From: Igor Radovanovic <74266147+IgorWounds@users.noreply.github.com>
Date: Tue, 12 Sep 2023 21:31:50 +0200
Subject: [PATCH] test_fetcher abstraction

---
 .../openbb_provider/abstract/fetcher.py       | 58 +++++++++++++++++--
 1 file changed, 53 insertions(+), 5 deletions(-)

diff --git a/openbb_sdk/sdk/provider/openbb_provider/abstract/fetcher.py b/openbb_sdk/sdk/provider/openbb_provider/abstract/fetcher.py
index d045cd57d19..7f2052af8ea 100644
--- a/openbb_sdk/sdk/provider/openbb_provider/abstract/fetcher.py
+++ b/openbb_sdk/sdk/provider/openbb_provider/abstract/fetcher.py
@@ -1,4 +1,6 @@
 """Abstract class for the fetcher."""
+# ruff: noqa: S101
+# pylint: disable=E1101
 
 
 from typing import Any, Dict, Generic, Optional, TypeVar, get_args, get_origin
@@ -77,8 +79,54 @@ class Fetcher(Generic[Q, R]):
         return data
 
     @classmethod
-    def test_fetcher(cls, params: Dict[str, Any], credentials: Dict[str, str]) -> R:
-        """Test the fetcher."""
-        query = cls.transform_query(params=params)
-        data = cls.extract_data(query=query, credentials=credentials)
-        return cls.transform_data(data=data)
+    def test_fetcher(
+        cls,
+        test_params: Dict[str, Any],
+        credentials: Optional[Dict[str, str]] = None,
+        **kwargs,
+    ) -> None:
+        """Test the fetcher.
+
+        This method will test each stage of the fetcher TET (Transform, Extract, Transform).
+
+        Args
+        ----
+            test_params: The params to test the fetcher with.
+            credentials: The credentials to test the fetcher with.
+
+        Raises
+        ------
+            AssertionError: If any of the tests fail.
+        """
+        query = cls.transform_query(params=test_params)
+        data = cls.extract_data(query=query, credentials=credentials, **kwargs)
+        transformed_data = cls.transform_data(data=data)
+
+        # Query Assertions
+        assert query
+        assert issubclass(type(query), cls.query_params_type)
+        assert all([getattr(query, key) == value for key, value in test_params.items()])
+
+        # Data Assertions
+        assert data
+        assert all([field in data[0] for field in cls.data_type.__fields__])
+        assert len(data) > 0
+        # This makes sure that the data is not transformed yet so that the
+        # pipeline is implemented correctly. We can remove this assertion if we
+        # want to be less strict.
+        assert issubclass(type(data[0]), cls.data_type) is False
+
+        # Transformed Data Assertions
+        assert transformed_data
+        assert all(
+            [
+                field in transformed_data[0].__dict__  # type: ignore
+                for field in cls.return_type.__args__[0].__fields__
+            ]
+        )
+        assert len(transformed_data) > 0  # type: ignore
+        assert issubclass(type(transformed_data[0]), cls.data_type)  # type: ignore
+        assert issubclass(
+            type(transformed_data[0]),  # type: ignore
+            cls.return_type.__args__[0],
+        )