# Create a docarray
    docs = DocArray[ImageDoc]([ImageDoc(tensor=np.zeros((3, 224, 224)))])

    app = FastAPI()
    # Always use our custom response class (needed to dump tensors)
    @app.post("/doc/", response_class=DocArrayResponse)
    async def func(fastapi_docs: List[ImageDoc]) -> List[ImageDoc]:
        # The docs FastAPI will receive will be treated as List[ImageDoc]
        # so you need to cast it to DocArray
        docarray_docs = DocArray[ImageDoc].construct(fastapi_docs)
        ...
        # In case you want to return a DocArray, return it as a list
        return list(docarray_docs)

    async with AsyncClient(app=app, base_url="http://test") as ac:
        response = await ac.post("/doc/", data=docs.to_json()) # sending docs as json

    assert response.status_code == 200
    # You can read FastAPI's response in the following way
    docs = DocArray[ImageDoc].from_json(response.content.decode())