vhdx-core 0.2.1

use std::io::Read;
use vhdx::VhdxReader;

fn data(name: &str) -> Vec<u8> {
    let path = std::path::PathBuf::from(env!("CARGO_MANIFEST_DIR"))
        .join("tests/data")
        .join(name);
    std::fs::read(&path).unwrap_or_else(|_| panic!("test data missing: {}", path.display()))
}

#[test]
fn fat_differential_with_parent_opens() {
    let parent = VhdxReader::from_bytes(data("fat-parent.vhdx")).expect("parent opens");
    VhdxReader::from_bytes_with_parent(data("fat-differential.vhdx"), parent)
        .expect("differential opens with parent");
}

#[test]
fn fat_differential_sector_0_readable() {
    let parent = VhdxReader::from_bytes(data("fat-parent.vhdx")).expect("parent opens");
    let mut diff = VhdxReader::from_bytes_with_parent(data("fat-differential.vhdx"), parent)
        .expect("differential opens");
    let mut buf = [0u8; 512];
    diff.read_exact(&mut buf).expect("sector 0 must be readable");
}

#[test]
fn fat_differential_virtual_disk_size_matches_parent() {
    let parent_bytes = data("fat-parent.vhdx");
    let parent_size = VhdxReader::from_bytes(parent_bytes.clone())
        .expect("parent opens")
        .virtual_disk_size();
    let parent2 = VhdxReader::from_bytes(parent_bytes).expect("parent re-opens");
    let diff = VhdxReader::from_bytes_with_parent(data("fat-differential.vhdx"), parent2)
        .expect("differential opens");
    assert_eq!(
        diff.virtual_disk_size(),
        parent_size,
        "child and parent virtual disk sizes must match"
    );
}

#[test]
fn from_bytes_still_refuses_differencing_disk() {
    let result = VhdxReader::from_bytes(data("fat-differential.vhdx"));
    assert!(
        result.is_err(),
        "from_bytes must still refuse a differencing disk without parent"
    );
}