library/test/src/lib.rs

   1 //! Support code for rustc's built in unit-test and micro-benchmarking
   2 //! framework.
   3 //!
   4 //! Almost all user code will only be interested in `Bencher` and
   5 //! `black_box`. All other interactions (such as writing tests and
   6 //! benchmarks themselves) should be done via the `#[test]` and
   7 //! `#[bench]` attributes.
   8 //!
   9 //! See the [Testing Chapter](../book/ch11-00-testing.html) of the book for more details.
  10
  11 // Currently, not much of this is meant for users. It is intended to
  12 // support the simplest interface possible for representing and
  13 // running tests while providing a base that other test frameworks may
  14 // build off of.
  15
  16 // N.B., this is also specified in this crate's Cargo.toml, but librustc_ast contains logic specific to
  17 // this crate, which relies on this attribute (rather than the value of `--crate-name` passed by
  18 // cargo) to detect this crate.
  19
  20 #![crate_name = "test"]
  21 #![unstable(feature = "test", issue = "50297")]
  22 #![doc(html_root_url = "https://doc.rust-lang.org/nightly/", test(attr(deny(warnings))))]
  23 #![cfg_attr(unix, feature(libc))]
  24 #![feature(rustc_private)]
  25 #![feature(nll)]
  26 #![feature(available_concurrency)]
  27 #![feature(bench_black_box)]
  28 #![feature(internal_output_capture)]
  29 #![feature(panic_unwind)]
  30 #![feature(staged_api)]
  31 #![feature(termination_trait_lib)]
  32 #![feature(test)]
  33 #![feature(total_cmp)]
  34
  35 // Public reexports
  36 pub use self::bench::{black_box, Bencher};
  37 pub use self::console::run_tests_console;
  38 pub use self::options::{ColorConfig, Options, OutputFormat, RunIgnored, ShouldPanic};
  39 pub use self::types::TestName::*;
  40 pub use self::types::*;
  41 pub use self::ColorConfig::*;
  42 pub use cli::TestOpts;
  43
  44 // Module to be used by rustc to compile tests in libtest
  45 pub mod test {
  46     pub use crate::{
  47         assert_test_result,
  48         bench::Bencher,
  49         cli::{parse_opts, TestOpts},
  50         filter_tests,
  51         helpers::metrics::{Metric, MetricMap},
  52         options::{Concurrent, Options, RunIgnored, RunStrategy, ShouldPanic},
  53         run_test, test_main, test_main_static,
  54         test_result::{TestResult, TrFailed, TrFailedMsg, TrIgnored, TrOk},
  55         time::{TestExecTime, TestTimeOptions},
  56         types::{
  57             DynTestFn, DynTestName, StaticBenchFn, StaticTestFn, StaticTestName, TestDesc,
  58             TestDescAndFn, TestId, TestName, TestType,
  59         },
  60     };
  61 }
  62
  63 use std::{
  64     collections::VecDeque,
  65     env, io,
  66     io::prelude::Write,
  67     panic::{self, catch_unwind, AssertUnwindSafe, PanicInfo},
  68     process::{self, Command, Termination},
  69     sync::mpsc::{channel, Sender},
  70     sync::{Arc, Mutex},
  71     thread,
  72     time::{Duration, Instant},
  73 };
  74
  75 pub mod bench;
  76 mod cli;
  77 mod console;
  78 mod event;
  79 mod formatters;
  80 mod helpers;
  81 mod options;
  82 pub mod stats;
  83 mod test_result;
  84 mod time;
  85 mod types;
  86
  87 #[cfg(test)]
  88 mod tests;
  89
  90 use event::{CompletedTest, TestEvent};
  91 use helpers::concurrency::get_concurrency;
  92 use helpers::exit_code::get_exit_code;
  93 use options::{Concurrent, RunStrategy};
  94 use test_result::*;
  95 use time::TestExecTime;
  96
  97 // Process exit code to be used to indicate test failures.
  98 const ERROR_EXIT_CODE: i32 = 101;
  99
 100 const SECONDARY_TEST_INVOKER_VAR: &str = "__RUST_TEST_INVOKE";
 101
 102 // The default console test runner. It accepts the command line
 103 // arguments and a vector of test_descs.
 104 pub fn test_main(args: &[String], tests: Vec<TestDescAndFn>, options: Option<Options>) {
 105     let mut opts = match cli::parse_opts(args) {
 106         Some(Ok(o)) => o,
 107         Some(Err(msg)) => {
 108             eprintln!("error: {}", msg);
 109             process::exit(ERROR_EXIT_CODE);
 110         }
 111         None => return,
 112     };
 113     if let Some(options) = options {
 114         opts.options = options;
 115     }
 116     if opts.list {
 117         if let Err(e) = console::list_tests_console(&opts, tests) {
 118             eprintln!("error: io error when listing tests: {:?}", e);
 119             process::exit(ERROR_EXIT_CODE);
 120         }
 121     } else {
 122         match console::run_tests_console(&opts, tests) {
 123             Ok(true) => {}
 124             Ok(false) => process::exit(ERROR_EXIT_CODE),
 125             Err(e) => {
 126                 eprintln!("error: io error when listing tests: {:?}", e);
 127                 process::exit(ERROR_EXIT_CODE);
 128             }
 129         }
 130     }
 131 }
 132
 133 /// A variant optimized for invocation with a static test vector.
 134 /// This will panic (intentionally) when fed any dynamic tests.
 135 ///
 136 /// This is the entry point for the main function generated by `rustc --test`
 137 /// when panic=unwind.
 138 pub fn test_main_static(tests: &[&TestDescAndFn]) {
 139     let args = env::args().collect::<Vec<_>>();
 140     let owned_tests: Vec<_> = tests.iter().map(make_owned_test).collect();
 141     test_main(&args, owned_tests, None)
 142 }
 143
 144 /// A variant optimized for invocation with a static test vector.
 145 /// This will panic (intentionally) when fed any dynamic tests.
 146 ///
 147 /// Runs tests in panic=abort mode, which involves spawning subprocesses for
 148 /// tests.
 149 ///
 150 /// This is the entry point for the main function generated by `rustc --test`
 151 /// when panic=abort.
 152 pub fn test_main_static_abort(tests: &[&TestDescAndFn]) {
 153     // If we're being run in SpawnedSecondary mode, run the test here. run_test
 154     // will then exit the process.
 155     if let Ok(name) = env::var(SECONDARY_TEST_INVOKER_VAR) {
 156         env::remove_var(SECONDARY_TEST_INVOKER_VAR);
 157         let test = tests
 158             .iter()
 159             .filter(|test| test.desc.name.as_slice() == name)
 160             .map(make_owned_test)
 161             .next()
 162             .unwrap_or_else(|| panic!("couldn't find a test with the provided name '{}'", name));
 163         let TestDescAndFn { desc, testfn } = test;
 164         let testfn = match testfn {
 165             StaticTestFn(f) => f,
 166             _ => panic!("only static tests are supported"),
 167         };
 168         run_test_in_spawned_subprocess(desc, Box::new(testfn));
 169     }
 170
 171     let args = env::args().collect::<Vec<_>>();
 172     let owned_tests: Vec<_> = tests.iter().map(make_owned_test).collect();
 173     test_main(&args, owned_tests, Some(Options::new().panic_abort(true)))
 174 }
 175
 176 /// Clones static values for putting into a dynamic vector, which test_main()
 177 /// needs to hand out ownership of tests to parallel test runners.
 178 ///
 179 /// This will panic when fed any dynamic tests, because they cannot be cloned.
 180 fn make_owned_test(test: &&TestDescAndFn) -> TestDescAndFn {
 181     match test.testfn {
 182         StaticTestFn(f) => TestDescAndFn { testfn: StaticTestFn(f), desc: test.desc.clone() },
 183         StaticBenchFn(f) => TestDescAndFn { testfn: StaticBenchFn(f), desc: test.desc.clone() },
 184         _ => panic!("non-static tests passed to test::test_main_static"),
 185     }
 186 }
 187
 188 /// Invoked when unit tests terminate. Should panic if the unit
 189 /// Tests is considered a failure. By default, invokes `report()`
 190 /// and checks for a `0` result.
 191 pub fn assert_test_result<T: Termination>(result: T) {
 192     let code = result.report();
 193     assert_eq!(
 194         code, 0,
 195         "the test returned a termination value with a non-zero status code ({}) \
 196          which indicates a failure",
 197         code
 198     );
 199 }
 200
 201 pub fn run_tests<F>(
 202     opts: &TestOpts,
 203     tests: Vec<TestDescAndFn>,
 204     mut notify_about_test_event: F,
 205 ) -> io::Result<()>
 206 where
 207     F: FnMut(TestEvent) -> io::Result<()>,
 208 {
 209     use std::collections::{self, HashMap};
 210     use std::hash::BuildHasherDefault;
 211     use std::sync::mpsc::RecvTimeoutError;
 212
 213     struct RunningTest {
 214         join_handle: Option<thread::JoinHandle<()>>,
 215     }
 216
 217     // Use a deterministic hasher
 218     type TestMap =
 219         HashMap<TestId, RunningTest, BuildHasherDefault<collections::hash_map::DefaultHasher>>;
 220
 221     struct TimeoutEntry {
 222         id: TestId,
 223         desc: TestDesc,
 224         timeout: Instant,
 225     }
 226
 227     let tests_len = tests.len();
 228
 229     let mut filtered_tests = filter_tests(opts, tests);
 230     if !opts.bench_benchmarks {
 231         filtered_tests = convert_benchmarks_to_tests(filtered_tests);
 232     }
 233
 234     let filtered_tests = {
 235         let mut filtered_tests = filtered_tests;
 236         for test in filtered_tests.iter_mut() {
 237             test.desc.name = test.desc.name.with_padding(test.testfn.padding());
 238         }
 239
 240         filtered_tests
 241     };
 242
 243     let filtered_out = tests_len - filtered_tests.len();
 244     let event = TestEvent::TeFilteredOut(filtered_out);
 245     notify_about_test_event(event)?;
 246
 247     let filtered_descs = filtered_tests.iter().map(|t| t.desc.clone()).collect();
 248
 249     let event = TestEvent::TeFiltered(filtered_descs);
 250     notify_about_test_event(event)?;
 251
 252     let (filtered_tests, filtered_benchs): (Vec<_>, _) = filtered_tests
 253         .into_iter()
 254         .enumerate()
 255         .map(|(i, e)| (TestId(i), e))
 256         .partition(|(_, e)| matches!(e.testfn, StaticTestFn(_) | DynTestFn(_)));
 257
 258     let concurrency = opts.test_threads.unwrap_or_else(get_concurrency);
 259
 260     let mut remaining = filtered_tests;
 261     remaining.reverse();
 262     let mut pending = 0;
 263
 264     let (tx, rx) = channel::<CompletedTest>();
 265     let run_strategy = if opts.options.panic_abort && !opts.force_run_in_process {
 266         RunStrategy::SpawnPrimary
 267     } else {
 268         RunStrategy::InProcess
 269     };
 270
 271     let mut running_tests: TestMap = HashMap::default();
 272     let mut timeout_queue: VecDeque<TimeoutEntry> = VecDeque::new();
 273
 274     fn get_timed_out_tests(
 275         running_tests: &TestMap,
 276         timeout_queue: &mut VecDeque<TimeoutEntry>,
 277     ) -> Vec<TestDesc> {
 278         let now = Instant::now();
 279         let mut timed_out = Vec::new();
 280         while let Some(timeout_entry) = timeout_queue.front() {
 281             if now < timeout_entry.timeout {
 282                 break;
 283             }
 284             let timeout_entry = timeout_queue.pop_front().unwrap();
 285             if running_tests.contains_key(&timeout_entry.id) {
 286                 timed_out.push(timeout_entry.desc);
 287             }
 288         }
 289         timed_out
 290     }
 291
 292     fn calc_timeout(timeout_queue: &VecDeque<TimeoutEntry>) -> Option<Duration> {
 293         timeout_queue.front().map(|&TimeoutEntry { timeout: next_timeout, .. }| {
 294             let now = Instant::now();
 295             if next_timeout >= now { next_timeout - now } else { Duration::new(0, 0) }
 296         })
 297     }
 298
 299     if concurrency == 1 {
 300         while !remaining.is_empty() {
 301             let (id, test) = remaining.pop().unwrap();
 302             let event = TestEvent::TeWait(test.desc.clone());
 303             notify_about_test_event(event)?;
 304             let join_handle =
 305                 run_test(opts, !opts.run_tests, id, test, run_strategy, tx.clone(), Concurrent::No);
 306             assert!(join_handle.is_none());
 307             let completed_test = rx.recv().unwrap();
 308
 309             let event = TestEvent::TeResult(completed_test);
 310             notify_about_test_event(event)?;
 311         }
 312     } else {
 313         while pending > 0 || !remaining.is_empty() {
 314             while pending < concurrency && !remaining.is_empty() {
 315                 let (id, test) = remaining.pop().unwrap();
 316                 let timeout = time::get_default_test_timeout();
 317                 let desc = test.desc.clone();
 318
 319                 let event = TestEvent::TeWait(desc.clone());
 320                 notify_about_test_event(event)?; //here no pad
 321                 let join_handle = run_test(
 322                     opts,
 323                     !opts.run_tests,
 324                     id,
 325                     test,
 326                     run_strategy,
 327                     tx.clone(),
 328                     Concurrent::Yes,
 329                 );
 330                 running_tests.insert(id, RunningTest { join_handle });
 331                 timeout_queue.push_back(TimeoutEntry { id, desc, timeout });
 332                 pending += 1;
 333             }
 334
 335             let mut res;
 336             loop {
 337                 if let Some(timeout) = calc_timeout(&timeout_queue) {
 338                     res = rx.recv_timeout(timeout);
 339                     for test in get_timed_out_tests(&running_tests, &mut timeout_queue) {
 340                         let event = TestEvent::TeTimeout(test);
 341                         notify_about_test_event(event)?;
 342                     }
 343
 344                     match res {
 345                         Err(RecvTimeoutError::Timeout) => {
 346                             // Result is not yet ready, continue waiting.
 347                         }
 348                         _ => {
 349                             // We've got a result, stop the loop.
 350                             break;
 351                         }
 352                     }
 353                 } else {
 354                     res = rx.recv().map_err(|_| RecvTimeoutError::Disconnected);
 355                     break;
 356                 }
 357             }
 358
 359             let mut completed_test = res.unwrap();
 360             let running_test = running_tests.remove(&completed_test.id).unwrap();
 361             if let Some(join_handle) = running_test.join_handle {
 362                 if let Err(_) = join_handle.join() {
 363                     if let TrOk = completed_test.result {
 364                         completed_test.result =
 365                             TrFailedMsg("panicked after reporting success".to_string());
 366                     }
 367                 }
 368             }
 369
 370             let event = TestEvent::TeResult(completed_test);
 371             notify_about_test_event(event)?;
 372             pending -= 1;
 373         }
 374     }
 375
 376     if opts.bench_benchmarks {
 377         // All benchmarks run at the end, in serial.
 378         for (id, b) in filtered_benchs {
 379             let event = TestEvent::TeWait(b.desc.clone());
 380             notify_about_test_event(event)?;
 381             run_test(opts, false, id, b, run_strategy, tx.clone(), Concurrent::No);
 382             let completed_test = rx.recv().unwrap();
 383
 384             let event = TestEvent::TeResult(completed_test);
 385             notify_about_test_event(event)?;
 386         }
 387     }
 388     Ok(())
 389 }
 390
 391 pub fn filter_tests(opts: &TestOpts, tests: Vec<TestDescAndFn>) -> Vec<TestDescAndFn> {
 392     let mut filtered = tests;
 393     let matches_filter = |test: &TestDescAndFn, filter: &str| {
 394         let test_name = test.desc.name.as_slice();
 395
 396         match opts.filter_exact {
 397             true => test_name == filter,
 398             false => test_name.contains(filter),
 399         }
 400     };
 401
 402     // Remove tests that don't match the test filter
 403     if !opts.filters.is_empty() {
 404         filtered.retain(|test| opts.filters.iter().any(|filter| matches_filter(test, filter)));
 405     }
 406
 407     // Skip tests that match any of the skip filters
 408     filtered.retain(|test| !opts.skip.iter().any(|sf| matches_filter(test, sf)));
 409
 410     // Excludes #[should_panic] tests
 411     if opts.exclude_should_panic {
 412         filtered.retain(|test| test.desc.should_panic == ShouldPanic::No);
 413     }
 414
 415     // maybe unignore tests
 416     match opts.run_ignored {
 417         RunIgnored::Yes => {
 418             filtered.iter_mut().for_each(|test| test.desc.ignore = false);
 419         }
 420         RunIgnored::Only => {
 421             filtered.retain(|test| test.desc.ignore);
 422             filtered.iter_mut().for_each(|test| test.desc.ignore = false);
 423         }
 424         RunIgnored::No => {}
 425     }
 426
 427     // Sort the tests alphabetically
 428     filtered.sort_by(|t1, t2| t1.desc.name.as_slice().cmp(t2.desc.name.as_slice()));
 429
 430     filtered
 431 }
 432
 433 pub fn convert_benchmarks_to_tests(tests: Vec<TestDescAndFn>) -> Vec<TestDescAndFn> {
 434     // convert benchmarks to tests, if we're not benchmarking them
 435     tests
 436         .into_iter()
 437         .map(|x| {
 438             let testfn = match x.testfn {
 439                 DynBenchFn(bench) => DynTestFn(Box::new(move || {
 440                     bench::run_once(|b| __rust_begin_short_backtrace(|| bench.run(b)))
 441                 })),
 442                 StaticBenchFn(benchfn) => DynTestFn(Box::new(move || {
 443                     bench::run_once(|b| __rust_begin_short_backtrace(|| benchfn(b)))
 444                 })),
 445                 f => f,
 446             };
 447             TestDescAndFn { desc: x.desc, testfn }
 448         })
 449         .collect()
 450 }
 451
 452 pub fn run_test(
 453     opts: &TestOpts,
 454     force_ignore: bool,
 455     id: TestId,
 456     test: TestDescAndFn,
 457     strategy: RunStrategy,
 458     monitor_ch: Sender<CompletedTest>,
 459     concurrency: Concurrent,
 460 ) -> Option<thread::JoinHandle<()>> {
 461     let TestDescAndFn { desc, testfn } = test;
 462
 463     // Emscripten can catch panics but other wasm targets cannot
 464     let ignore_because_no_process_support = desc.should_panic != ShouldPanic::No
 465         && cfg!(target_arch = "wasm32")
 466         && !cfg!(target_os = "emscripten");
 467
 468     if force_ignore || desc.ignore || ignore_because_no_process_support {
 469         let message = CompletedTest::new(id, desc, TrIgnored, None, Vec::new());
 470         monitor_ch.send(message).unwrap();
 471         return None;
 472     }
 473
 474     struct TestRunOpts {
 475         pub strategy: RunStrategy,
 476         pub nocapture: bool,
 477         pub concurrency: Concurrent,
 478         pub time: Option<time::TestTimeOptions>,
 479     }
 480
 481     fn run_test_inner(
 482         id: TestId,
 483         desc: TestDesc,
 484         monitor_ch: Sender<CompletedTest>,
 485         testfn: Box<dyn FnOnce() + Send>,
 486         opts: TestRunOpts,
 487     ) -> Option<thread::JoinHandle<()>> {
 488         let concurrency = opts.concurrency;
 489         let name = desc.name.clone();
 490
 491         let runtest = move || match opts.strategy {
 492             RunStrategy::InProcess => run_test_in_process(
 493                 id,
 494                 desc,
 495                 opts.nocapture,
 496                 opts.time.is_some(),
 497                 testfn,
 498                 monitor_ch,
 499                 opts.time,
 500             ),
 501             RunStrategy::SpawnPrimary => spawn_test_subprocess(
 502                 id,
 503                 desc,
 504                 opts.nocapture,
 505                 opts.time.is_some(),
 506                 monitor_ch,
 507                 opts.time,
 508             ),
 509         };
 510
 511         // If the platform is single-threaded we're just going to run
 512         // the test synchronously, regardless of the concurrency
 513         // level.
 514         let supports_threads = !cfg!(target_os = "emscripten") && !cfg!(target_arch = "wasm32");
 515         if concurrency == Concurrent::Yes && supports_threads {
 516             let cfg = thread::Builder::new().name(name.as_slice().to_owned());
 517             let mut runtest = Arc::new(Mutex::new(Some(runtest)));
 518             let runtest2 = runtest.clone();
 519             match cfg.spawn(move || runtest2.lock().unwrap().take().unwrap()()) {
 520                 Ok(handle) => Some(handle),
 521                 Err(e) if e.kind() == io::ErrorKind::WouldBlock => {
 522                     // `ErrorKind::WouldBlock` means hitting the thread limit on some
 523                     // platforms, so run the test synchronously here instead.
 524                     Arc::get_mut(&mut runtest).unwrap().get_mut().unwrap().take().unwrap()();
 525                     None
 526                 }
 527                 Err(e) => panic!("failed to spawn thread to run test: {}", e),
 528             }
 529         } else {
 530             runtest();
 531             None
 532         }
 533     }
 534
 535     let test_run_opts =
 536         TestRunOpts { strategy, nocapture: opts.nocapture, concurrency, time: opts.time_options };
 537
 538     match testfn {
 539         DynBenchFn(bencher) => {
 540             // Benchmarks aren't expected to panic, so we run them all in-process.
 541             crate::bench::benchmark(id, desc, monitor_ch, opts.nocapture, |harness| {
 542                 bencher.run(harness)
 543             });
 544             None
 545         }
 546         StaticBenchFn(benchfn) => {
 547             // Benchmarks aren't expected to panic, so we run them all in-process.
 548             crate::bench::benchmark(id, desc, monitor_ch, opts.nocapture, benchfn);
 549             None
 550         }
 551         DynTestFn(f) => {
 552             match strategy {
 553                 RunStrategy::InProcess => (),
 554                 _ => panic!("Cannot run dynamic test fn out-of-process"),
 555             };
 556             run_test_inner(
 557                 id,
 558                 desc,
 559                 monitor_ch,
 560                 Box::new(move || __rust_begin_short_backtrace(f)),
 561                 test_run_opts,
 562             )
 563         }
 564         StaticTestFn(f) => run_test_inner(
 565             id,
 566             desc,
 567             monitor_ch,
 568             Box::new(move || __rust_begin_short_backtrace(f)),
 569             test_run_opts,
 570         ),
 571     }
 572 }
 573
 574 /// Fixed frame used to clean the backtrace with `RUST_BACKTRACE=1`.
 575 #[inline(never)]
 576 fn __rust_begin_short_backtrace<F: FnOnce()>(f: F) {
 577     f();
 578
 579     // prevent this frame from being tail-call optimised away
 580     black_box(());
 581 }
 582
 583 fn run_test_in_process(
 584     id: TestId,
 585     desc: TestDesc,
 586     nocapture: bool,
 587     report_time: bool,
 588     testfn: Box<dyn FnOnce() + Send>,
 589     monitor_ch: Sender<CompletedTest>,
 590     time_opts: Option<time::TestTimeOptions>,
 591 ) {
 592     // Buffer for capturing standard I/O
 593     let data = Arc::new(Mutex::new(Vec::new()));
 594
 595     if !nocapture {
 596         io::set_output_capture(Some(data.clone()));
 597     }
 598
 599     let start = report_time.then(Instant::now);
 600     let result = catch_unwind(AssertUnwindSafe(testfn));
 601     let exec_time = start.map(|start| {
 602         let duration = start.elapsed();
 603         TestExecTime(duration)
 604     });
 605
 606     io::set_output_capture(None);
 607
 608     let test_result = match result {
 609         Ok(()) => calc_result(&desc, Ok(()), &time_opts, &exec_time),
 610         Err(e) => calc_result(&desc, Err(e.as_ref()), &time_opts, &exec_time),
 611     };
 612     let stdout = data.lock().unwrap_or_else(|e| e.into_inner()).to_vec();
 613     let message = CompletedTest::new(id, desc, test_result, exec_time, stdout);
 614     monitor_ch.send(message).unwrap();
 615 }
 616
 617 fn spawn_test_subprocess(
 618     id: TestId,
 619     desc: TestDesc,
 620     nocapture: bool,
 621     report_time: bool,
 622     monitor_ch: Sender<CompletedTest>,
 623     time_opts: Option<time::TestTimeOptions>,
 624 ) {
 625     let (result, test_output, exec_time) = (|| {
 626         let args = env::args().collect::<Vec<_>>();
 627         let current_exe = &args[0];
 628
 629         let mut command = Command::new(current_exe);
 630         command.env(SECONDARY_TEST_INVOKER_VAR, desc.name.as_slice());
 631         if nocapture {
 632             command.stdout(process::Stdio::inherit());
 633             command.stderr(process::Stdio::inherit());
 634         }
 635
 636         let start = report_time.then(Instant::now);
 637         let output = match command.output() {
 638             Ok(out) => out,
 639             Err(e) => {
 640                 let err = format!("Failed to spawn {} as child for test: {:?}", args[0], e);
 641                 return (TrFailed, err.into_bytes(), None);
 642             }
 643         };
 644         let exec_time = start.map(|start| {
 645             let duration = start.elapsed();
 646             TestExecTime(duration)
 647         });
 648
 649         let std::process::Output { stdout, stderr, status } = output;
 650         let mut test_output = stdout;
 651         formatters::write_stderr_delimiter(&mut test_output, &desc.name);
 652         test_output.extend_from_slice(&stderr);
 653
 654         let result = match (|| -> Result<TestResult, String> {
 655             let exit_code = get_exit_code(status)?;
 656             Ok(get_result_from_exit_code(&desc, exit_code, &time_opts, &exec_time))
 657         })() {
 658             Ok(r) => r,
 659             Err(e) => {
 660                 write!(&mut test_output, "Unexpected error: {}", e).unwrap();
 661                 TrFailed
 662             }
 663         };
 664
 665         (result, test_output, exec_time)
 666     })();
 667
 668     let message = CompletedTest::new(id, desc, result, exec_time, test_output);
 669     monitor_ch.send(message).unwrap();
 670 }
 671
 672 fn run_test_in_spawned_subprocess(desc: TestDesc, testfn: Box<dyn FnOnce() + Send>) -> ! {
 673     let builtin_panic_hook = panic::take_hook();
 674     let record_result = Arc::new(move |panic_info: Option<&'_ PanicInfo<'_>>| {
 675         let test_result = match panic_info {
 676             Some(info) => calc_result(&desc, Err(info.payload()), &None, &None),
 677             None => calc_result(&desc, Ok(()), &None, &None),
 678         };
 679
 680         // We don't support serializing TrFailedMsg, so just
 681         // print the message out to stderr.
 682         if let TrFailedMsg(msg) = &test_result {
 683             eprintln!("{}", msg);
 684         }
 685
 686         if let Some(info) = panic_info {
 687             builtin_panic_hook(info);
 688         }
 689
 690         if let TrOk = test_result {
 691             process::exit(test_result::TR_OK);
 692         } else {
 693             process::exit(test_result::TR_FAILED);
 694         }
 695     });
 696     let record_result2 = record_result.clone();
 697     panic::set_hook(Box::new(move |info| record_result2(Some(&info))));
 698     testfn();
 699     record_result(None);
 700     unreachable!("panic=abort callback should have exited the process")
 701 }