docs(streaming): combine testing your code to be more realistic

Author: heitorlessa

docs/utilities/streaming.md

@@ -131,32 +131,18 @@ You can build your own custom data transformation by extending the `BaseTransfor
 
 ## Testing your code
 
-### Testing that you transformation is applied
-
-Test that your transformation pipeline is returning the correct object:
-
-=== "Testing the data pipeline returned object"
-
-    ```python hl_lines="14 17"
-    --8<-- "examples/streaming/src/test_s3_pipeline_result.py"
-    ```
-
-### Testing that your transformation is working in isolation
+### Asserting data transformations
 
 Create an input payload using `io.BytesIO` and assert the response of the transformation:
 
-=== "Testing transformation in isolation"
+=== "assert_transformation.py"
 
-    ```python hl_lines="23-25"
-    --8<-- "examples/streaming/src/test_s3_transform_isolated.py"
+    ```python hl_lines="3 13 15 23-28 31-32"
+    --8<-- "examples/streaming/src/assert_transformation.py"
     ```
 
-### Testing that your transformation is working with S3 data
-
-Use `botocore.stub` to stub the `get_object` response from S3:
-
-=== "Testing transformation with mocked S3 data"
+=== "assert_transformation_module.py"
 
-    ```python hl_lines="32-34 37"
-    --8<-- "examples/streaming/src/test_s3_transform_mocked.py"
+    ```python hl_lines="16"
+    --8<-- "examples/streaming/src/assert_transformation_module.py"
     ```

examples/streaming/src/assert_transformation.py

@@ -0,0 +1,35 @@
+import io
+
+import boto3
+from assert_transformation_module import UpperTransform
+from botocore import stub
+
+from aws_lambda_powertools.utilities.streaming import S3Object
+from aws_lambda_powertools.utilities.streaming.compat import PowertoolsStreamingBody
+
+
+def test_upper_transform():
+    # GIVEN
+    data_stream = io.BytesIO(b"hello world")
+    # WHEN
+    data_stream = UpperTransform().transform(data_stream)
+    # THEN
+    assert data_stream.read() == b"HELLO WORLD"
+
+
+def test_s3_object_with_upper_transform():
+    # GIVEN
+    payload = b"hello world"
+    s3_client = boto3.client("s3")
+    s3_stub = stub.Stubber(s3_client)
+    s3_stub.add_response(
+        "get_object", {"Body": PowertoolsStreamingBody(raw_stream=io.BytesIO(payload), content_length=len(payload))}
+    )
+    s3_stub.activate()
+
+    # WHEN
+    data_stream = S3Object(bucket="bucket", key="key", boto3_client=s3_client)
+    data_stream.transform(UpperTransform(), in_place=True)
+
+    # THEN
+    assert data_stream.read() == b"HELLO WORLD"

examples/streaming/src/test_s3_transform_isolated.py renamed to examples/streaming/src/assert_transformation_module.py

@@ -17,9 +17,3 @@ def read(self, size: int = -1) -> Optional[bytes]:
 class UpperTransform(BaseTransform):
     def transform(self, input_stream: IO[bytes]) -> UpperIO:
         return UpperIO(input_stream=input_stream, encoding="utf-8")
-
-
-def test_s3_pipeline_result():
-    stream = io.BytesIO(b"hello world")
-    stream = UpperTransform().transform(stream)
-    assert stream.read() == b"HELLO WORLD"