From dca83d73cbfe847738cbd310a4da786979768dd0 Mon Sep 17 00:00:00 2001
From: David Cook <divergentdave@gmail.com>
Date: Thu, 20 Feb 2020 22:19:51 -0600
Subject: [PATCH] Add test that exercises ReentrantMutex

---
 tests/run-pass/reentrant-println.rs     | 17 +++++++++++++++++
 tests/run-pass/reentrant-println.stdout |  2 ++
 2 files changed, 19 insertions(+)
 create mode 100644 tests/run-pass/reentrant-println.rs
 create mode 100644 tests/run-pass/reentrant-println.stdout

diff --git a/tests/run-pass/reentrant-println.rs b/tests/run-pass/reentrant-println.rs
new file mode 100644
index 00000000000..3703d21e042
--- /dev/null
+++ b/tests/run-pass/reentrant-println.rs
@@ -0,0 +1,17 @@
+use std::fmt::{Display, Error, Formatter};
+
+// This test case exercises std::sys_common::remutex::ReentrantMutex
+// by calling println!() from inside fmt
+
+struct InterruptingCow();
+
+impl Display for InterruptingCow {
+    fn fmt(&self, _f: &mut Formatter<'_>) -> Result<(), Error> {
+        println!("Moo");
+        Ok(())
+    }
+}
+
+fn main() {
+    println!("\"Knock knock\" \"Who's {} there?\"", InterruptingCow());
+}
diff --git a/tests/run-pass/reentrant-println.stdout b/tests/run-pass/reentrant-println.stdout
new file mode 100644
index 00000000000..8a57d32f84c
--- /dev/null
+++ b/tests/run-pass/reentrant-println.stdout
@@ -0,0 +1,2 @@
+"Knock knock" "Who's Moo
+ there?"