1 files changed, 65 insertions, 0 deletions
diff --git a/vendor/tracing/tests/filter_caching_is_lexically_scoped.rs b/vendor/tracing/tests/filter_caching_is_lexically_scoped.rs
new file mode 100644
index 000000000..e291103d7
--- /dev/null
+++ b/vendor/tracing/tests/filter_caching_is_lexically_scoped.rs
@@ -0,0 +1,65 @@
+// Tests that depend on a count of the number of times their filter is evaluated
+// can't exist in the same file with other tests that add subscribers to the
+// registry. The registry was changed so that each time a new dispatcher is
+// added all filters are re-evaluated. The tests being run only in separate
+// threads with shared global state lets them interfere with each other
+
+#[cfg(not(feature = "std"))]
+extern crate std;
+
+use tracing::{span, Level};
+use tracing_mock::*;
+
+use std::sync::{
+    atomic::{AtomicUsize, Ordering},
+    Arc,
+};
+
+#[cfg_attr(target_arch = "wasm32", wasm_bindgen_test::wasm_bindgen_test)]
+#[test]
+fn filter_caching_is_lexically_scoped() {
+    pub fn my_great_function() -> bool {
+        span!(Level::TRACE, "emily").in_scope(|| true)
+    }
+
+    pub fn my_other_function() -> bool {
+        span!(Level::TRACE, "frank").in_scope(|| true)
+    }
+
+    let count = Arc::new(AtomicUsize::new(0));
+    let count2 = count.clone();
+
+    let subscriber = subscriber::mock()
+        .with_filter(move |meta| match meta.name() {
+            "emily" | "frank" => {
+                count2.fetch_add(1, Ordering::Relaxed);
+                true
+            }
+            _ => false,
+        })
+        .run();
+
+    // Since this test is in its own file anyway, we can do this. Thus, this
+    // test will work even with no-std.
+    tracing::subscriber::set_global_default(subscriber).unwrap();
+
+    // Call the function once. The filter should be re-evaluated.
+    assert!(my_great_function());
+    assert_eq!(count.load(Ordering::Relaxed), 1);
+
+    // Call the function again. The cached result should be used.
+    assert!(my_great_function());
+    assert_eq!(count.load(Ordering::Relaxed), 1);
+
+    assert!(my_other_function());
+    assert_eq!(count.load(Ordering::Relaxed), 2);
+
+    assert!(my_great_function());
+    assert_eq!(count.load(Ordering::Relaxed), 2);
+
+    assert!(my_other_function());
+    assert_eq!(count.load(Ordering::Relaxed), 2);
+
+    assert!(my_great_function());
+    assert_eq!(count.load(Ordering::Relaxed), 2);
+}