AppTest fails on re-run if selectbox options are non-strings

[NakulK48]

Checklist

• I have searched the existing issues for similar issues.
• I added a very descriptive title to this issue.
• I have provided sufficient information below to help reproduce this issue.

Summary

In regular Streamlit, the options argument of a selectbox can be any iterable, as long as there is a format_func provided to go from the item type to a string.

However, testing.v1.element_tree contains the function:

    @property
    def index(self) -> int | None:
        """The index of the current selection. (int)"""
        if self.value is None:
            return None

        if len(self.options) == 0:
            return 0
        return self.options.index(str(self.value))

What ends up happening here is that self.value is of the type of the actual element (populated during the first call to run(), and self.options is a list of strings. As a result, Python raises an error because the value is not in the list of options.

Reproducible Code Example

def test_broken_streamlit():
    def func():
        from dataclasses import dataclass

        @dataclass
        class Foo:
            name: str

        import streamlit as st
        st.selectbox("foo", options=[Foo("bar"), Foo("baz")], format_func=lambda x: x.name)

    at = AppTest.from_function(func)
    at.run()
    at.run()

(the example is contrived for simplicity: more likely you'd do something like at.text_input("some_element").input("boo").run())

Steps To Reproduce

No response

Expected Behavior

Either options should be a list of Foo (this seems more sensible to me), or value should be the formatted string

Current Behavior

self = Selectbox(_value=InitialValue(), label='foo', options=['bar', 'baz'])

    @property
    def index(self) -> int | None:
        """The index of the current selection. (int)"""
        if self.value is None:
            return None

        if len(self.options) == 0:
            return 0
>       return self.options.index(str(self.value))
E       ValueError: "Foo(name='bar')" is not in list

../../mambaforge/envs/dlf-ui/lib/python3.10/site-packages/streamlit/testing/v1/element_tree.py:930: ValueError

Is this a regression?

• Yes, this used to work in a previous version.

Debug info

• Streamlit version: 1.28.0
• Python version: 3.10.8
• Operating System:
• Browser: AppTest

Additional Information

No response

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