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Diffstat (limited to 'vendor/tracing-subscriber/tests/support.rs')
| -rw-r--r-- | vendor/tracing-subscriber/tests/support.rs | 407 |
1 files changed, 407 insertions, 0 deletions
diff --git a/vendor/tracing-subscriber/tests/support.rs b/vendor/tracing-subscriber/tests/support.rs new file mode 100644 index 000000000..50e0e6669 --- /dev/null +++ b/vendor/tracing-subscriber/tests/support.rs @@ -0,0 +1,407 @@ +#![allow(missing_docs, dead_code)] +pub use tracing_mock::{event, field, span, subscriber}; + +use tracing_core::{ + span::{Attributes, Id, Record}, + Event, Subscriber, +}; +use tracing_mock::{ + event::MockEvent, + span::{MockSpan, NewSpan}, + subscriber::{Expect, MockHandle}, +}; +use tracing_subscriber::{ + layer::{Context, Layer}, + registry::{LookupSpan, SpanRef}, +}; + +use std::{ + collections::VecDeque, + fmt, + sync::{Arc, Mutex}, +}; + +pub mod layer { + use super::ExpectLayerBuilder; + + pub fn mock() -> ExpectLayerBuilder { + ExpectLayerBuilder { + expected: Default::default(), + name: std::thread::current() + .name() + .map(String::from) + .unwrap_or_default(), + } + } + + pub fn named(name: impl std::fmt::Display) -> ExpectLayerBuilder { + mock().named(name) + } +} + +pub struct ExpectLayerBuilder { + expected: VecDeque<Expect>, + name: String, +} + +pub struct ExpectLayer { + expected: Arc<Mutex<VecDeque<Expect>>>, + current: Mutex<Vec<Id>>, + name: String, +} + +impl ExpectLayerBuilder { + /// Overrides the name printed by the mock subscriber's debugging output. + /// + /// The debugging output is displayed if the test panics, or if the test is + /// run with `--nocapture`. + /// + /// By default, the mock subscriber's name is the name of the test + /// (*technically*, the name of the thread where it was created, which is + /// the name of the test unless tests are run with `--test-threads=1`). + /// When a test has only one mock subscriber, this is sufficient. However, + /// some tests may include multiple subscribers, in order to test + /// interactions between multiple subscribers. In that case, it can be + /// helpful to give each subscriber a separate name to distinguish where the + /// debugging output comes from. + pub fn named(mut self, name: impl fmt::Display) -> Self { + use std::fmt::Write; + if !self.name.is_empty() { + write!(&mut self.name, "::{}", name).unwrap(); + } else { + self.name = name.to_string(); + } + self + } + + pub fn enter(mut self, span: MockSpan) -> Self { + self.expected.push_back(Expect::Enter(span)); + self + } + + pub fn event(mut self, event: MockEvent) -> Self { + self.expected.push_back(Expect::Event(event)); + self + } + + pub fn exit(mut self, span: MockSpan) -> Self { + self.expected.push_back(Expect::Exit(span)); + self + } + + pub fn done(mut self) -> Self { + self.expected.push_back(Expect::Nothing); + self + } + + pub fn record<I>(mut self, span: MockSpan, fields: I) -> Self + where + I: Into<field::Expect>, + { + self.expected.push_back(Expect::Visit(span, fields.into())); + self + } + + pub fn new_span<I>(mut self, new_span: I) -> Self + where + I: Into<NewSpan>, + { + self.expected.push_back(Expect::NewSpan(new_span.into())); + self + } + + pub fn run(self) -> ExpectLayer { + ExpectLayer { + expected: Arc::new(Mutex::new(self.expected)), + name: self.name, + current: Mutex::new(Vec::new()), + } + } + + pub fn run_with_handle(self) -> (ExpectLayer, MockHandle) { + let expected = Arc::new(Mutex::new(self.expected)); + let handle = MockHandle::new(expected.clone(), self.name.clone()); + let layer = ExpectLayer { + expected, + name: self.name, + current: Mutex::new(Vec::new()), + }; + (layer, handle) + } +} + +impl ExpectLayer { + fn check_span_ref<'spans, S>( + &self, + expected: &MockSpan, + actual: &SpanRef<'spans, S>, + what_happened: impl fmt::Display, + ) where + S: LookupSpan<'spans>, + { + if let Some(exp_name) = expected.name() { + assert_eq!( + actual.name(), + exp_name, + "\n[{}] expected {} a span named {:?}\n\ + [{}] but it was named {:?} instead (span {} {:?})", + self.name, + what_happened, + exp_name, + self.name, + actual.name(), + actual.name(), + actual.id() + ); + } + + if let Some(exp_level) = expected.level() { + let actual_level = actual.metadata().level(); + assert_eq!( + actual_level, + &exp_level, + "\n[{}] expected {} a span at {:?}\n\ + [{}] but it was at {:?} instead (span {} {:?})", + self.name, + what_happened, + exp_level, + self.name, + actual_level, + actual.name(), + actual.id(), + ); + } + + if let Some(exp_target) = expected.target() { + let actual_target = actual.metadata().target(); + assert_eq!( + actual_target, + exp_target, + "\n[{}] expected {} a span with target {:?}\n\ + [{}] but it had the target {:?} instead (span {} {:?})", + self.name, + what_happened, + exp_target, + self.name, + actual_target, + actual.name(), + actual.id(), + ); + } + } +} + +impl<S> Layer<S> for ExpectLayer +where + S: Subscriber + for<'a> LookupSpan<'a>, +{ + fn register_callsite( + &self, + metadata: &'static tracing::Metadata<'static>, + ) -> tracing_core::Interest { + println!("[{}] register_callsite {:#?}", self.name, metadata); + tracing_core::Interest::always() + } + + fn on_record(&self, _: &Id, _: &Record<'_>, _: Context<'_, S>) { + unimplemented!( + "so far, we don't have any tests that need an `on_record` \ + implementation.\nif you just wrote one that does, feel free to \ + implement it!" + ); + } + + fn on_event(&self, event: &Event<'_>, cx: Context<'_, S>) { + let name = event.metadata().name(); + println!( + "[{}] event: {}; level: {}; target: {}", + self.name, + name, + event.metadata().level(), + event.metadata().target(), + ); + match self.expected.lock().unwrap().pop_front() { + None => {} + Some(Expect::Event(mut expected)) => { + let get_parent_name = || cx.event_span(event).map(|span| span.name().to_string()); + expected.check(event, get_parent_name, &self.name); + let mut current_scope = cx.event_scope(event).into_iter().flatten(); + let expected_scope = expected.scope_mut(); + let mut i = 0; + for (expected, actual) in expected_scope.iter_mut().zip(&mut current_scope) { + println!( + "[{}] event_scope[{}] actual={} ({:?}); expected={}", + self.name, + i, + actual.name(), + actual.id(), + expected + ); + self.check_span_ref( + expected, + &actual, + format_args!("the {}th span in the event's scope to be", i), + ); + i += 1; + } + let remaining_expected = &expected_scope[i..]; + assert!( + remaining_expected.is_empty(), + "\n[{}] did not observe all expected spans in event scope!\n[{}] missing: {:#?}", + self.name, + self.name, + remaining_expected, + ); + assert!( + current_scope.next().is_none(), + "\n[{}] did not expect all spans in the actual event scope!", + self.name, + ); + } + Some(ex) => ex.bad(&self.name, format_args!("observed event {:#?}", event)), + } + } + + fn on_follows_from(&self, _span: &Id, _follows: &Id, _: Context<'_, S>) { + // TODO: it should be possible to expect spans to follow from other spans + } + + fn on_new_span(&self, span: &Attributes<'_>, id: &Id, cx: Context<'_, S>) { + let meta = span.metadata(); + println!( + "[{}] new_span: name={:?}; target={:?}; id={:?};", + self.name, + meta.name(), + meta.target(), + id + ); + let mut expected = self.expected.lock().unwrap(); + let was_expected = matches!(expected.front(), Some(Expect::NewSpan(_))); + if was_expected { + if let Expect::NewSpan(mut expected) = expected.pop_front().unwrap() { + let get_parent_name = || { + span.parent() + .and_then(|id| cx.span(id)) + .or_else(|| cx.lookup_current()) + .map(|span| span.name().to_string()) + }; + expected.check(span, get_parent_name, &self.name); + } + } + } + + fn on_enter(&self, id: &Id, cx: Context<'_, S>) { + let span = cx + .span(id) + .unwrap_or_else(|| panic!("[{}] no span for ID {:?}", self.name, id)); + println!("[{}] enter: {}; id={:?};", self.name, span.name(), id); + match self.expected.lock().unwrap().pop_front() { + None => {} + Some(Expect::Enter(ref expected_span)) => { + self.check_span_ref(expected_span, &span, "to enter"); + } + Some(ex) => ex.bad(&self.name, format_args!("entered span {:?}", span.name())), + } + self.current.lock().unwrap().push(id.clone()); + } + + fn on_exit(&self, id: &Id, cx: Context<'_, S>) { + if std::thread::panicking() { + // `exit()` can be called in `drop` impls, so we must guard against + // double panics. + println!("[{}] exit {:?} while panicking", self.name, id); + return; + } + let span = cx + .span(id) + .unwrap_or_else(|| panic!("[{}] no span for ID {:?}", self.name, id)); + println!("[{}] exit: {}; id={:?};", self.name, span.name(), id); + match self.expected.lock().unwrap().pop_front() { + None => {} + Some(Expect::Exit(ref expected_span)) => { + self.check_span_ref(expected_span, &span, "to exit"); + let curr = self.current.lock().unwrap().pop(); + assert_eq!( + Some(id), + curr.as_ref(), + "[{}] exited span {:?}, but the current span was {:?}", + self.name, + span.name(), + curr.as_ref().and_then(|id| cx.span(id)).map(|s| s.name()) + ); + } + Some(ex) => ex.bad(&self.name, format_args!("exited span {:?}", span.name())), + }; + } + + fn on_close(&self, id: Id, cx: Context<'_, S>) { + if std::thread::panicking() { + // `try_close` can be called in `drop` impls, so we must guard against + // double panics. + println!("[{}] close {:?} while panicking", self.name, id); + return; + } + let span = cx.span(&id); + let name = span.as_ref().map(|span| { + println!("[{}] close_span: {}; id={:?};", self.name, span.name(), id,); + span.name() + }); + if name.is_none() { + println!("[{}] drop_span: id={:?}", self.name, id); + } + if let Ok(mut expected) = self.expected.try_lock() { + let was_expected = match expected.front() { + Some(Expect::DropSpan(ref expected_span)) => { + // Don't assert if this function was called while panicking, + // as failing the assertion can cause a double panic. + if !::std::thread::panicking() { + if let Some(ref span) = span { + self.check_span_ref(expected_span, span, "to close"); + } + } + true + } + Some(Expect::Event(_)) => { + if !::std::thread::panicking() { + panic!( + "[{}] expected an event, but dropped span {} (id={:?}) instead", + self.name, + name.unwrap_or("<unknown name>"), + id + ); + } + true + } + _ => false, + }; + if was_expected { + expected.pop_front(); + } + } + } + + fn on_id_change(&self, _old: &Id, _new: &Id, _ctx: Context<'_, S>) { + panic!("well-behaved subscribers should never do this to us, lol"); + } +} + +impl fmt::Debug for ExpectLayer { + fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result { + let mut s = f.debug_struct("ExpectLayer"); + s.field("name", &self.name); + + if let Ok(expected) = self.expected.try_lock() { + s.field("expected", &expected); + } else { + s.field("expected", &format_args!("<locked>")); + } + + if let Ok(current) = self.current.try_lock() { + s.field("current", &format_args!("{:?}", ¤t)); + } else { + s.field("current", &format_args!("<locked>")); + } + + s.finish() + } +} |