//! `kernel test`, driven through the built binary against a fixture tree.
//!
//! Nothing here boots a kernel: qemu is taken off `PATH` deliberately, so the
//! assertions are about the paths around the boot rather than about a machine
//! that can run one. The real boot is the plan's P6 manual step.

mod common;

use common::Fixture;

/// A fixture tree with something at the path qemu would be handed.
fn fixture_with_image() -> Fixture {
    let fixture = Fixture::kernel_tree();
    fixture.write("arch/x86/boot/bzImage", "not really a kernel\n");
    fixture.commit_all("fixture: add an image");

    fixture
}

#[test]
fn a_missing_qemu_is_named_rather_than_panicked_on() {
    let fixture = fixture_with_image();
    // A `PATH` with nothing on it: the binary itself is found by its full
    // path, and qemu cannot be.
    let bare = fixture.restricted_path(&[]);

    let output = fixture.cli_env(
        &["kernel", "test", "--no-build"],
        &[("PATH", bare.to_str().expect("the restricted path"))],
    );

    assert_eq!(output.status.code(), Some(1));
    let stderr = String::from_utf8_lossy(&output.stderr);
    assert!(
        stderr.contains("could not run `qemu-system-x86_64`"),
        "{stderr}"
    );
    assert!(
        !String::from_utf8_lossy(&output.stdout).contains("exited cleanly"),
        "a boot that never started was reported as a success"
    );
}

#[test]
fn a_tree_with_no_image_is_named_rather_than_a_build_being_attempted() {
    let fixture = Fixture::kernel_tree();

    let output = fixture.cli(&["kernel", "test", "--no-build"]);

    assert_eq!(output.status.code(), Some(1));
    let stderr = String::from_utf8_lossy(&output.stderr);
    assert!(stderr.contains("no bootable image at"), "{stderr}");
    assert!(stderr.contains("arch/x86/boot/bzImage"), "{stderr}");
}

#[test]
fn build_runs_make_in_the_tree_and_finds_the_image_it_wrote() {
    // A Makefile that writes the image where a real build leaves it, and
    // records that it ran. `sh` is the only tool it needs, so the restricted
    // `PATH` can hold make and sh and still leave qemu out.
    let fixture = Fixture::kernel_tree();
    fixture.write("arch/x86/boot/.keep", "");
    fixture.write(
        "Makefile",
        "all:\n\tprintf '' > arch/x86/boot/bzImage\n\tprintf 'built\\n' > .make-call\n",
    );
    fixture.commit_all("fixture: add a Makefile");
    let bin = fixture.restricted_path(&["make", "sh"]);

    let output = fixture.cli_env(
        &["kernel", "test"],
        &[("PATH", bin.to_str().expect("the restricted path"))],
    );

    assert_eq!(
        fixture.read(".make-call"),
        "built\n",
        "make did not run in the tree"
    );
    // The image check passed, which is why the failure is qemu's rather than
    // the image's.
    assert_eq!(output.status.code(), Some(1));
    let stderr = String::from_utf8_lossy(&output.stderr);
    assert!(
        stderr.contains("could not run `qemu-system-x86_64`"),
        "the build did not get as far as qemu: {stderr}"
    );
}

#[test]
fn qemu_runs_with_the_arguments_the_plan_describes() {
    // What qemu was handed, captured without needing a real qemu: the stub is
    // reached through `PATH`, so the binary under test cannot tell.
    let fixture = fixture_with_image();
    fixture.write_script(
        "bin/qemu-system-x86_64",
        "#!/bin/sh\necho \"argv: $*\"\nexit 1\n",
    );
    let bin = fixture.join("bin");

    let output = fixture.cli_env(
        &[
            "kernel",
            "test",
            "--no-build",
            "--qemu-arg",
            "-m",
            "--qemu-arg",
            "1G",
        ],
        &[("PATH", bin.to_str().expect("the stub bin directory"))],
    );

    assert_eq!(
        output.status.code(),
        Some(1),
        "a failing qemu must not look clean: {}",
        String::from_utf8_lossy(&output.stdout)
    );
    let stdout = String::from_utf8_lossy(&output.stdout);
    assert!(
        stdout.contains("-kernel ") && stdout.contains("arch/x86/boot/bzImage"),
        "{stdout}"
    );
    assert!(
        stdout.contains("-append console=ttyS0"),
        "the console is what makes a boot readable: {stdout}"
    );
    assert!(stdout.contains("-nographic"), "{stdout}");
    assert!(stdout.contains("-m 1G"), "the pass-through args: {stdout}");
    assert!(
        stdout.contains("qemu exited with status 1"),
        "the exit status was flattened: {stdout}"
    );
}