From aceccc72f2f4727946a0114c0526adc95b029272 Mon Sep 17 00:00:00 2001
From: Titouan Rigoudy <titouan.rigoudy@gmail.com>
Date: Sun, 26 May 2019 21:12:44 +0000
Subject: [PATCH] WIP: Add tests for Executor.

---
 src/context.rs  |  3 ++-
 src/executor.rs | 59 ++++++++++++++++++++++++++++++++++++++++++++++---
 2 files changed, 58 insertions(+), 4 deletions(-)

diff --git a/src/context.rs b/src/context.rs
index 776605a..13257f6 100644
--- a/src/context.rs
+++ b/src/context.rs
@@ -9,6 +9,7 @@ use crate::user::UserMap;
 /// Contains all the different bits of client state.
 ///
 /// Implements `Sync`.
+#[derive(Debug)]
 pub struct Context {
     pub rooms: Mutex<RoomMap>,
     pub users: Mutex<UserMap>,
@@ -26,8 +27,8 @@ impl Context {
 
 #[cfg(test)]
 mod tests {
-    use std::thread;
     use std::sync::Arc;
+    use std::thread;
 
     use super::Context;
 
diff --git a/src/executor.rs b/src/executor.rs
index 710508d..df32058 100644
--- a/src/executor.rs
+++ b/src/executor.rs
@@ -50,8 +50,61 @@ impl Executor {
         })
     }
 
-    /// Blocks until all scheduled jobs are executed.
-    pub fn join(self) {
-        self.pool.join()
+    /// Blocks until all scheduled jobs are executed, then returns the context.
+    pub fn join(self) -> Context {
+        self.pool.join();
+
+        // Once the pool is joined, no-one should be holding on to copies of
+        // `self.context` anymore, so we unwrap() here.
+        Arc::try_unwrap(self.context).unwrap()
+    }
+}
+
+#[cfg(test)]
+mod tests {
+    use std::io;
+    use std::sync::{Arc, Barrier, Mutex};
+
+    use super::{Context, Executor, Job};
+
+    #[test]
+    fn immediate_join_returns_empty_context() {
+        let context = Executor::new().join();
+        assert_eq!(context.users.lock().get_list(), vec![]);
+        assert_eq!(context.rooms.lock().get_room_list(), vec![]);
+    }
+
+    struct Waiter {
+        pub barrier: Arc<Barrier>,
+    }
+
+    impl Job for Waiter {
+        fn execute(self: Box<Self>, context: &Context) -> io::Result<()> {
+            self.barrier.wait();
+            Ok(())
+        }
     }
+
+    #[test]
+    fn join_waits_for_all_jobs() {
+        let executor = Executor::new();
+
+        let barrier = Arc::new(Barrier::new(2));
+
+        let waiter1 = Box::new(Waiter {
+            barrier: barrier.clone(),
+        });
+        let waiter2 = Box::new(Waiter {
+            barrier: barrier.clone(),
+        });
+
+        executor.schedule(waiter1);
+        executor.schedule(waiter2);
+
+        let context = executor.join();
+        assert_eq!(context.users.lock().get_list(), vec![]);
+        assert_eq!(context.rooms.lock().get_room_list(), vec![]);
+    }
+
+    // TODO: Add a test that exercises modifying Context.
 }