tvl-depot/tvix/eval/tests/nix_oracle.rs

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//! Tests which use upstream nix as an oracle to test evaluation against
use std::{env, path::PathBuf, process::Command};
use pretty_assertions::assert_eq;
use tempdir::TempDir;
fn nix_binary_path() -> PathBuf {
env::var("NIX_INSTANTIATE_BINARY_PATH")
.unwrap_or_else(|_| "nix-instantiate".to_owned())
.into()
}
fn nix_eval(expr: &str) -> String {
let store_dir = TempDir::new("store-dir").unwrap();
let output = Command::new(nix_binary_path())
.args(["--eval", "--strict", "-E"])
.arg(format!("({expr})"))
.env(
"NIX_REMOTE",
format!("local?root={}", store_dir.path().display()),
)
.output()
.unwrap();
if !output.status.success() {
panic!(
"nix eval {expr} failed!\n stdout: {}\n stderr: {}",
String::from_utf8_lossy(&output.stdout),
String::from_utf8_lossy(&output.stderr)
)
}
String::from_utf8(output.stdout).unwrap()
}
/// Compare the evaluation of the given nix expression in nix (using the
/// `NIX_INSTANTIATE_BINARY_PATH` env var to resolve the `nix-instantiate` binary) and tvix, and
/// assert that the result is identical
#[track_caller]
fn compare_eval(expr: &str) {
let nix_result = nix_eval(expr);
let mut eval = tvix_eval::Evaluation::new(expr, None);
eval.io_handle = Box::new(tvix_eval::StdIO);
let tvix_result = eval
.evaluate()
.value
.expect("tvix evaluation should succeed")
.to_string();
assert_eq!(nix_result.trim(), tvix_result);
}
/// Generate a suite of tests which call [`compare_eval`] on expressions, checking that nix and tvix
/// return identical results.
macro_rules! compare_eval_tests {
() => {};
($(#[$meta:meta])* $test_name: ident($expr: expr); $($rest:tt)*) => {
#[test]
$(#[$meta])*
fn $test_name() {
compare_eval($expr);
}
compare_eval_tests!($($rest)*);
}
}
compare_eval_tests! {
literal_int("1");
add_ints("1 + 1");
add_lists("[1 2] ++ [3 4]");
add_paths(r#"[
(./. + "/")
(./foo + "bar")
(let name = "bar"; in ./foo + name)
(let name = "bar"; in ./foo + "${name}")
(let name = "bar"; in ./foo + "/" + "${name}")
(let name = "bar"; in ./foo + "/${name}")
(./. + ./.)
]"#);
}