feat(harness): Allow tests access to send events (#122)

`TestContext` exposes `notify(Event)` and `test_name` / `elapsed_s` to
create an `Event`

Author: epage

crates/libtest2-harness/src/context.rs

@@ -1,9 +1,11 @@
 pub(crate) use crate::*;
 
-#[derive(Debug)]
 pub struct TestContext {
-    mode: RunMode,
-    run_ignored: bool,
+    pub(crate) start: std::time::Instant,
+    pub(crate) mode: RunMode,
+    pub(crate) run_ignored: bool,
+    pub(crate) notifier: notify::ArcNotifier,
+    pub(crate) test_name: String,
 }
 
 impl TestContext {
@@ -26,21 +28,30 @@ impl TestContext {
     pub fn current_mode(&self) -> RunMode {
         self.mode
     }
-}
 
-impl TestContext {
-    pub(crate) fn new() -> Self {
-        Self {
-            mode: Default::default(),
-            run_ignored: false,
-        }
+    pub fn notify(&self, event: notify::Event) -> std::io::Result<()> {
+        self.notifier().notify(event)
+    }
+
+    pub fn elapased_s(&self) -> notify::Elapsed {
+        notify::Elapsed(self.start.elapsed())
+    }
+
+    pub fn test_name(&self) -> &str {
+        &self.test_name
     }
 
-    pub(crate) fn set_mode(&mut self, mode: RunMode) {
-        self.mode = mode;
+    pub(crate) fn notifier(&self) -> &notify::ArcNotifier {
+        &self.notifier
     }
 
-    pub(crate) fn set_run_ignored(&mut self, yes: bool) {
-        self.run_ignored = yes;
+    pub(crate) fn clone(&self) -> Self {
+        Self {
+            start: self.start,
+            mode: self.mode,
+            run_ignored: self.run_ignored,
+            notifier: self.notifier.clone(),
+            test_name: self.test_name.clone(),
+        }
     }
 }

crates/libtest2-harness/src/harness.rs

@@ -83,14 +83,14 @@ impl Harness<StateArgs> {
 pub struct StateParsed {
     start: std::time::Instant,
     opts: libtest_lexarg::TestOpts,
-    notifier: Box<dyn notify::Notifier>,
+    notifier: notify::ArcNotifier,
 }
 impl HarnessState for StateParsed {}
 impl sealed::_HarnessState_is_Sealed for StateParsed {}
 
 impl Harness<StateParsed> {
     pub fn discover(
-        mut self,
+        self,
         cases: impl IntoIterator<Item = impl Case + 'static>,
     ) -> std::io::Result<Harness<StateDiscovered>> {
         self.state.notifier.notify(
@@ -144,22 +144,22 @@ impl Harness<StateParsed> {
 pub struct StateDiscovered {
     start: std::time::Instant,
     opts: libtest_lexarg::TestOpts,
-    notifier: Box<dyn notify::Notifier>,
+    notifier: notify::ArcNotifier,
     cases: Vec<Box<dyn Case>>,
 }
 impl HarnessState for StateDiscovered {}
 impl sealed::_HarnessState_is_Sealed for StateDiscovered {}
 
 impl Harness<StateDiscovered> {
-    pub fn run(mut self) -> std::io::Result<bool> {
+    pub fn run(self) -> std::io::Result<bool> {
         if self.state.opts.list {
             Ok(true)
         } else {
             run(
                 &self.state.start,
                 &self.state.opts,
                 self.state.cases,
-                self.state.notifier.as_mut(),
+                self.state.notifier,
             )
         }
     }
@@ -252,16 +252,16 @@ fn parse<'p>(parser: &mut cli::Parser<'p>) -> Result<libtest_lexarg::TestOpts, c
     Ok(opts)
 }
 
-fn notifier(opts: &libtest_lexarg::TestOpts) -> Box<dyn notify::Notifier> {
+fn notifier(opts: &libtest_lexarg::TestOpts) -> notify::ArcNotifier {
     #[cfg(feature = "color")]
     let stdout = anstream::stdout();
     #[cfg(not(feature = "color"))]
     let stdout = std::io::stdout();
     match opts.format {
-        OutputFormat::Json => Box::new(notify::JsonNotifier::new(stdout)),
-        _ if opts.list => Box::new(notify::TerseListNotifier::new(stdout)),
-        OutputFormat::Pretty => Box::new(notify::PrettyRunNotifier::new(stdout)),
-        OutputFormat::Terse => Box::new(notify::TerseRunNotifier::new(stdout)),
+        OutputFormat::Json => notify::ArcNotifier::new(notify::JsonNotifier::new(stdout)),
+        _ if opts.list => notify::ArcNotifier::new(notify::TerseListNotifier::new(stdout)),
+        OutputFormat::Pretty => notify::ArcNotifier::new(notify::PrettyRunNotifier::new(stdout)),
+        OutputFormat::Terse => notify::ArcNotifier::new(notify::TerseRunNotifier::new(stdout)),
     }
 }
 
@@ -292,7 +292,7 @@ fn run(
     start: &std::time::Instant,
     opts: &libtest_lexarg::TestOpts,
     cases: Vec<Box<dyn Case>>,
-    notifier: &mut dyn notify::Notifier,
+    notifier: notify::ArcNotifier,
 ) -> std::io::Result<bool> {
     notifier.notify(
         notify::event::RunStart {
@@ -316,7 +316,6 @@ fn run(
 
     let threads = opts.test_threads.map(|t| t.get()).unwrap_or(1);
 
-    let mut context = TestContext::new();
     let run_ignored = match opts.run_ignored {
         libtest_lexarg::RunIgnored::Yes | libtest_lexarg::RunIgnored::Only => true,
         libtest_lexarg::RunIgnored::No => false,
@@ -331,9 +330,13 @@ fn run(
         (false, true) => RunMode::Bench,
         (false, false) => unreachable!("libtest-lexarg` should always ensure at least one is set"),
     };
-    context.set_mode(mode);
-    context.set_run_ignored(run_ignored);
-    let context = std::sync::Arc::new(context);
+    let context = TestContext {
+        start: *start,
+        mode,
+        run_ignored,
+        notifier,
+        test_name: String::new(),
+    };
 
     let mut success = true;
 
@@ -345,88 +348,49 @@ fn run(
             .partition::<Vec<_>, _>(|c| c.exclusive(&context))
     };
     if !concurrent_cases.is_empty() {
-        notifier.threaded(true);
-        struct RunningTest {
-            join_handle: std::thread::JoinHandle<()>,
-        }
-
-        impl RunningTest {
-            fn join(
-                self,
-                start: &std::time::Instant,
-                event: &notify::event::CaseComplete,
-                notifier: &mut dyn notify::Notifier,
-            ) -> std::io::Result<()> {
-                if self.join_handle.join().is_err() {
-                    let kind = notify::MessageKind::Error;
-                    let message = Some("panicked after reporting success".to_owned());
-                    notifier.notify(
-                        notify::event::CaseMessage {
-                            name: event.name.clone(),
-                            kind,
-                            message,
-                            elapsed_s: Some(notify::Elapsed(start.elapsed())),
-                        }
-                        .into(),
-                    )?;
-                }
-                Ok(())
-            }
-        }
+        context.notifier().threaded(true);
 
         // Use a deterministic hasher
         type TestMap = std::collections::HashMap<
             String,
-            RunningTest,
+            std::thread::JoinHandle<std::io::Result<bool>>,
             std::hash::BuildHasherDefault<std::collections::hash_map::DefaultHasher>,
         >;
 
         let sync_success = std::sync::Arc::new(std::sync::atomic::AtomicBool::new(success));
-        let mut running_tests: TestMap = Default::default();
-        let mut pending = 0;
-        let (tx, rx) = std::sync::mpsc::channel::<notify::Event>();
+        let mut running: TestMap = Default::default();
+        let (tx, rx) = std::sync::mpsc::channel::<String>();
         let mut remaining = std::collections::VecDeque::from(concurrent_cases);
-        while pending > 0 || !remaining.is_empty() {
-            while pending < threads && !remaining.is_empty() {
+        while !running.is_empty() || !remaining.is_empty() {
+            while running.len() < threads && !remaining.is_empty() {
                 let case = remaining.pop_front().unwrap();
+                let case = std::sync::Arc::new(case);
                 let name = case.name().to_owned();
 
                 let cfg = std::thread::Builder::new().name(name.clone());
-                let start = *start;
-                let tx = tx.clone();
-                let case = std::sync::Arc::new(case);
-                let case_fallback = case.clone();
-                let context = context.clone();
-                let context_fallback = context.clone();
-                let sync_success = sync_success.clone();
-                let sync_success_fallback = sync_success.clone();
+                let thread_tx = tx.clone();
+                let thread_case = case.clone();
+                let mut thread_context = context.clone();
+                thread_context.test_name = name.clone();
+                let thread_sync_success = sync_success.clone();
                 let join_handle = cfg.spawn(move || {
-                    let mut notifier = SenderNotifier { tx: tx.clone() };
-                    let case_success =
-                        run_case(&start, case.as_ref().as_ref(), &context, &mut notifier)
-                            .expect("`SenderNotifier` is infallible");
-                    if !case_success {
-                        sync_success.store(case_success, std::sync::atomic::Ordering::Relaxed);
+                    let status = run_case(thread_case.as_ref().as_ref(), &thread_context);
+                    if !matches!(status, Ok(true)) {
+                        thread_sync_success.store(false, std::sync::atomic::Ordering::Relaxed);
                     }
+                    let _ = thread_tx.send(thread_case.name().to_owned());
+                    status
                 });
                 match join_handle {
                     Ok(join_handle) => {
-                        running_tests.insert(name.clone(), RunningTest { join_handle });
-                        pending += 1;
+                        running.insert(name.clone(), join_handle);
                     }
                     Err(e) if e.kind() == std::io::ErrorKind::WouldBlock => {
                         // `ErrorKind::WouldBlock` means hitting the thread limit on some
                         // platforms, so run the test synchronously here instead.
-                        let case_success = run_case(
-                            &start,
-                            case_fallback.as_ref().as_ref(),
-                            &context_fallback,
-                            notifier,
-                        )
-                        .expect("`SenderNotifier` is infallible");
+                        let case_success = run_case(case.as_ref().as_ref(), &context)?;
                         if !case_success {
-                            sync_success_fallback
-                                .store(case_success, std::sync::atomic::Ordering::Relaxed);
+                            sync_success.store(case_success, std::sync::atomic::Ordering::Relaxed);
                         }
                     }
                     Err(e) => {
@@ -435,13 +399,9 @@ fn run(
                 }
             }
 
-            let event = rx.recv().unwrap();
-            if let notify::Event::CaseComplete(event) = &event {
-                let running_test = running_tests.remove(&event.name).unwrap();
-                running_test.join(start, event, notifier)?;
-                pending -= 1;
-            }
-            notifier.notify(event)?;
+            let test_name = rx.recv().unwrap();
+            let running_test = running.remove(&test_name).unwrap();
+            let _ = running_test.join();
             success &= sync_success.load(std::sync::atomic::Ordering::SeqCst);
             if !success && opts.fail_fast {
                 break;
@@ -450,16 +410,16 @@ fn run(
     }
 
     if !exclusive_cases.is_empty() {
-        notifier.threaded(false);
+        context.notifier().threaded(false);
         for case in exclusive_cases {
-            success &= run_case(start, case.as_ref(), &context, notifier)?;
+            success &= run_case(case.as_ref(), &context)?;
             if !success && opts.fail_fast {
                 break;
             }
         }
     }
 
-    notifier.notify(
+    context.notifier().notify(
         notify::event::RunComplete {
             elapsed_s: Some(notify::Elapsed(start.elapsed())),
         }
@@ -469,16 +429,11 @@ fn run(
     Ok(success)
 }
 
-fn run_case(
-    start: &std::time::Instant,
-    case: &dyn Case,
-    context: &TestContext,
-    notifier: &mut dyn notify::Notifier,
-) -> std::io::Result<bool> {
-    notifier.notify(
+fn run_case(case: &dyn Case, context: &TestContext) -> std::io::Result<bool> {
+    context.notifier().notify(
         notify::event::CaseStart {
             name: case.name().to_owned(),
-            elapsed_s: Some(notify::Elapsed(start.elapsed())),
+            elapsed_s: Some(context.elapased_s()),
         }
         .into(),
     )?;
@@ -507,21 +462,21 @@ fn run_case(
         let kind = err.status();
         case_status = Some(kind);
         let message = err.cause().map(|c| c.to_string());
-        notifier.notify(
+        context.notifier().notify(
             notify::event::CaseMessage {
                 name: case.name().to_owned(),
                 kind,
                 message,
-                elapsed_s: Some(notify::Elapsed(start.elapsed())),
+                elapsed_s: Some(context.elapased_s()),
             }
             .into(),
         )?;
     }
 
-    notifier.notify(
+    context.notifier().notify(
         notify::event::CaseComplete {
             name: case.name().to_owned(),
-            elapsed_s: Some(notify::Elapsed(start.elapsed())),
+            elapsed_s: Some(context.elapased_s()),
         }
         .into(),
     )?;
@@ -537,16 +492,3 @@ fn __rust_begin_short_backtrace<T, F: FnOnce() -> T>(f: F) -> T {
     // prevent this frame from being tail-call optimised away
     std::hint::black_box(result)
 }
-
-#[derive(Clone, Debug)]
-struct SenderNotifier {
-    tx: std::sync::mpsc::Sender<notify::Event>,
-}
-
-impl notify::Notifier for SenderNotifier {
-    fn notify(&mut self, event: notify::Event) -> std::io::Result<()> {
-        // If the sender doesn't care, neither do we
-        let _ = self.tx.send(event);
-        Ok(())
-    }
-}