Got it! Here’s a minimal pytest that verifies a Prefect Secret is used to authenticate to an external API. It uses a mocked endpoint so you don’t need real credentials. Assumptions: - Prefect 3.x - pytest + responses for HTTP mocking Test code (unit-style with a mocked API):

import requests
import responses
from prefect import flow
from prefect.blocks.system import Secret

# A simple flow that loads a secret and calls an external API with it
@flow
def call_protected_endpoint() -> int:
    token = Secret.load("my-api-token").get()
    resp = requests.get(
        "<https://api.example.com/protected>",
        headers={"Authorization": f"Bearer {token}"},
        timeout=10,
    )
    resp.raise_for_status()
    return resp.status_code

@responses.activate
def test_secret_auth_success(monkeypatch):
    # If you have a Prefect API (Cloud/Server) available, you can save the block:
    # Secret(value="TEST_TOKEN").save("my-api-token", overwrite=True)
    #
    # If you don't have a Prefect API running in tests, patch the load instead:
    monkeypatch.setattr(
        Secret,
        "load",
        staticmethod(lambda name: Secret(value="TEST_TOKEN"))
    )

    # Mock the protected endpoint to require the expected auth header
    def auth_check(request):
        auth = request.headers.get("Authorization")
        if auth == "Bearer TEST_TOKEN":
            return (200, {}, "OK")
        return (401, {}, "Unauthorized")

    responses.add_callback(
        responses.GET,
        "<https://api.example.com/protected>",
        callback=auth_check,
        content_type="text/plain",
    )

    # Run the flow and assert we authenticated successfully
    status = call_protected_endpoint()
    assert status == 200

Notes: - If you want to test against a real Secret block saved in your workspace and a real endpoint, remove the

monkeypatch

and ensure a Secret named

my-api-token

exists with a valid value. Saving requires a running Prefect API (Prefect Cloud or a local Prefect Server). - Install deps: -

pip install pytest responses requests prefect

- Run:

pytest -q

Docs for reference: - Blocks and Secrets overview: https://docs.prefect.io/latest/concepts/blocks/