In the new FastAPI test, BODY_FORM substitutes {{image_data}} with str(base64.b64encode(open(PICTURE, "rb").read())). Wrapping the bytes returned by b64encode in str() yields the Python bytes repr (e.g. b'/9j/...', including the b' prefix and trailing quote) rather than a valid base64 string, so the multipart body sent to /body/form contains malformed base64 for the photo field. The Django ASGI equivalent (tests/integrations/django/asgi/test_asgi.py:664) correctly uses .decode("utf-8"). The test still passes because it only asserts the photo field is captured as "" (line 176), masking the defect. Use .decode("utf-8") instead of str().

Also found at:

• tests/integrations/fastapi/test_fastapi.py:166

The three new POST-body tests (test_request_info_json_body, test_formdata_request_body, test_request_body_too_big) pass only StarletteIntegration() to sentry_init, so FastApiIntegration is not activated. Since these were adapted from the Starlette suite into a test(fastapi) PR, they should register FastApiIntegration() alongside StarletteIntegration() (as most other tests in this file do) so the FastAPI-specific code path is exercised. This is a test-completeness/consistency gap, not a functional defect: request body capture is handled by Starlette's ASGI middleware, so the tests still pass.