mod common;
use std::path::{Path, PathBuf};
use std::process::Command;
use std::sync::atomic::{AtomicU64, Ordering};
use common::expect_tested;
use testing_conventions::mutation::{measure_rust, Measurement};
const CARGO_TOML: &str =
"[package]\nname = \"tc_mut_base\"\nversion = \"0.0.0\"\nedition = \"2021\"\n\n[workspace]\n";
const BASELINE: &str = r#"
pub fn add(a: i32, b: i32) -> i32 {
a + b
}
#[cfg(test)]
mod tests {
use super::*;
#[test]
fn adds() {
assert_eq!(add(2, 3), 5);
assert_eq!(add(10, 1), 11);
}
}
"#;
const WITH_SURVIVOR: &str = r#"
pub fn add(a: i32, b: i32) -> i32 {
a + b
}
pub fn is_positive(n: i32) -> bool {
n > 0
}
#[cfg(test)]
mod tests {
use super::*;
#[test]
fn adds() {
assert_eq!(add(2, 3), 5);
assert_eq!(add(10, 1), 11);
}
#[test]
fn runs_is_positive() {
let _ = is_positive(1);
}
}
"#;
struct TempRepo(PathBuf);
impl TempRepo {
fn new(slug: &str) -> Self {
let repo = Self::bare(slug);
repo.write("Cargo.toml", CARGO_TOML);
repo
}
fn bare(slug: &str) -> Self {
static COUNTER: AtomicU64 = AtomicU64::new(0);
let root = std::env::temp_dir().join(format!(
"tc-mut-base-{}-{}-{}",
slug,
std::process::id(),
COUNTER.fetch_add(1, Ordering::Relaxed),
));
std::fs::create_dir_all(&root).unwrap();
git(&root, &["init", "-q"]);
git(&root, &["config", "user.email", "test@example.com"]);
git(&root, &["config", "user.name", "Test"]);
TempRepo(root)
}
fn write(&self, rel: &str, contents: &str) {
let path = self.0.join(rel);
std::fs::create_dir_all(path.parent().unwrap()).unwrap();
std::fs::write(path, contents).unwrap();
}
fn commit(&self, message: &str) {
git(&self.0, &["add", "-A"]);
git(
&self.0,
&["-c", "commit.gpgsign=false", "commit", "-q", "-m", message],
);
}
fn head(&self) -> String {
let out = Command::new("git")
.args(["rev-parse", "HEAD"])
.current_dir(&self.0)
.output()
.expect("git rev-parse should run");
assert!(out.status.success(), "git rev-parse failed");
String::from_utf8(out.stdout).unwrap().trim().to_string()
}
}
impl Drop for TempRepo {
fn drop(&mut self) {
let _ = std::fs::remove_dir_all(&self.0);
}
}
fn git(dir: &Path, args: &[&str]) {
let status = Command::new("git")
.args(args)
.current_dir(dir)
.status()
.expect("git should run");
assert!(status.success(), "git {args:?} failed");
}
#[test]
fn base_scopes_the_run_to_the_changed_function() {
let repo = TempRepo::new("survivor");
repo.write("src/lib.rs", BASELINE);
repo.commit("baseline: fully-tested add");
let base = repo.head();
repo.write("src/lib.rs", WITH_SURVIVOR);
repo.commit("add an assertion-light is_positive");
let (count, survivors) = expect_tested(
measure_rust(
&repo.0,
&[],
&std::collections::BTreeMap::new(),
Some(&base),
&[],
)
.expect("cargo-mutants runs"),
);
assert!(
count >= survivors.len(),
"every survivor was judged, so the count covers them"
);
assert!(
!survivors.is_empty(),
"the added weak function should leave a survivor on the changed lines"
);
assert!(
survivors
.iter()
.all(|s| s.description.contains("is_positive")),
"only the changed `is_positive` should be mutated; got {survivors:?}"
);
}
#[test]
fn base_finds_survivors_in_a_subdir_crate() {
let repo = TempRepo::bare("subdir-survivor");
repo.write("crate/Cargo.toml", CARGO_TOML);
repo.write("crate/src/lib.rs", BASELINE);
repo.commit("baseline: fully-tested add in a subdir crate");
let base = repo.head();
repo.write("crate/src/lib.rs", WITH_SURVIVOR);
repo.commit("add an assertion-light is_positive");
let (_, survivors) = expect_tested(
measure_rust(
&repo.0.join("crate"),
&[],
&std::collections::BTreeMap::new(),
Some(&base),
&[],
)
.expect("cargo-mutants runs"),
);
assert!(
!survivors.is_empty()
&& survivors
.iter()
.all(|s| s.description.contains("is_positive")),
"the added weak function in the subdir crate should leave a survivor; got {survivors:?}"
);
}
const MEMBER_CARGO_TOML: &str =
"[package]\nname = \"tc_mut_member\"\nversion = \"0.0.0\"\nedition = \"2021\"\n";
#[test]
fn base_finds_survivors_in_a_workspace_member_crate() {
let repo = TempRepo::bare("workspace-member");
repo.write(
"Cargo.toml",
"[workspace]\nmembers = [\"member\"]\nresolver = \"2\"\n",
);
repo.write("member/Cargo.toml", MEMBER_CARGO_TOML);
repo.write("member/src/lib.rs", BASELINE);
repo.commit("baseline: fully-tested add in a workspace member");
let base = repo.head();
repo.write("member/src/lib.rs", WITH_SURVIVOR);
repo.commit("add an assertion-light is_positive");
let (_, survivors) = expect_tested(
measure_rust(
&repo.0.join("member"),
&[],
&std::collections::BTreeMap::new(),
Some(&base),
&[],
)
.expect("cargo-mutants runs"),
);
assert!(
!survivors.is_empty()
&& survivors
.iter()
.all(|s| s.description.contains("is_positive")),
"the added weak function in the workspace member should leave a survivor; got {survivors:?}"
);
assert!(
survivors.iter().all(|s| s.file == "src/lib.rs"),
"survivor paths are scan-path-relative, not workspace-relative; got {survivors:?}"
);
}
#[test]
fn base_with_only_non_source_crate_changes_reports_the_engine_not_run() {
let repo = TempRepo::new("readme-only");
repo.write("src/lib.rs", WITH_SURVIVOR);
repo.write("README.md", "before\n");
repo.commit("baseline");
let base = repo.head();
repo.write("README.md", "before\nafter\n");
repo.commit("edit the crate README, not its source");
let measurement = measure_rust(
&repo.0,
&[],
&std::collections::BTreeMap::new(),
Some(&base),
&[],
)
.expect("no run needed");
assert_eq!(
measurement,
Measurement::EngineNotRun,
"no Rust source changed, so the engine never ran"
);
}
#[test]
fn base_with_no_changes_under_the_crate_reports_the_engine_not_run() {
let repo = TempRepo::bare("subdir-nochange");
repo.write("crate/Cargo.toml", CARGO_TOML);
repo.write("crate/src/lib.rs", WITH_SURVIVOR);
repo.write("notes.md", "before\n");
repo.commit("baseline");
let base = repo.head();
repo.write("notes.md", "before\nafter\n");
repo.commit("tweak a top-level note, not the crate");
let measurement = measure_rust(
&repo.0.join("crate"),
&[],
&std::collections::BTreeMap::new(),
Some(&base),
&[],
)
.expect("no run needed");
assert_eq!(
measurement,
Measurement::EngineNotRun,
"nothing under the crate changed, so the engine never ran"
);
}