test: get file size by func metadata

[zhuliquan]

Which issue does this PR close?

Closes #11574.

Rationale for this change

fix failure running of case test_csv_parallel_one_col on windows machine

What changes are included in this PR?

getting file_size according to func metadata instead of target_os

Are these changes tested?

yes

Are there any user-facing changes?

no

[alamb]

I wonder how this test is passing on CI? In theory we run these tests on CI:

https://github.com/apache/datafusion/actions/runs/10044145872/job/27758535504

but somehow this test does not appear to run 🤔

[alamb]

Thanks @zhuliquan -- this makes sense to me.

I don't understand how this issue isn't caught on the CI runner though

[zhuliquan]

Thanks @zhuliquan -- this makes sense to me.

I don't understand how this issue isn't caught on the CI runner though

I also got confused, #[cfg(target_os)] not equal to windows?
I'am not sure that ci run unittests on real windows machine according to workflow yaml.

datafusion/.github/workflows/rust.yml

Lines 323 to 338 in 77311a5

	windows:
	name: cargo test (win64)
	runs-on: windows-latest
	steps:
	- uses: actions/checkout@v4
	with:
	submodules: true
	- name: Setup Rust toolchain
	uses: ./.github/actions/setup-windows-builder
	- name: Run tests (excluding doctests)
	shell: bash
	run: |
	export PATH=$PATH:$HOME/d/protoc/bin
	cargo test --lib --tests --bins --features avro,json,backtrace
	cd datafusion-cli
	cargo test --lib --tests --bins --all-features

[alamb]

I'am not sure that ci run unittests on real windows machine according to workflow yaml.

Or maybe it runs in WSL or something

[alamb]

Anyhow, thanks again @zhuliquan