How to test custom argument/option autocomplete functionality?

[mbergen]

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Example Code

from typer import Typer, Argument
from typer.testing import CliRunner
from typing import Annotated

app = Typer()

def autocomplete():
    """A function fetching autocomplete options from an API"""
    return ["Alpha", "Bravo", "Charlie"]

@app.command()
def cmd(name: Annotated[str, Argument(autocompletion=autocomplete)]):
    print(name)

result = CliRunner().invoke(app, "cmd", input="\t\t")

Description

Given a command with an argument with custom autocomplete logic, is there a way to test the autocomplete functionality in pytest?
While it would be possible to test just the autocomplete functionality in a unittest on its own, this is not really suitable in cases where the autocomplete for one argument depends on one of the other arguments/options.
For such cases, it would make sense if there is a way to test the autocompletion using the CliRunner somehow.

Operating System

Linux

Operating System Details

Rocky Linux 8

Typer Version

0.21.1

Python Version

3.12

Additional Context

No response