[core] add ask pattern to actor ref

1 files changed, 55 insertions, 3 deletions

diff --git a/test/actor/actor_ref.test.cpp b/test/actor/actor_ref.test.cpp
index 78721c965e..52b0de295b 100644
--- a/test/actor/actor_ref.test.cpp
+++ b/test/actor/actor_ref.test.cpp
@@ -3,12 +3,9 @@
 
 #include <mbgl/test/util.hpp>
 
-#include <chrono>
-#include <functional>
 #include <future>
 
 using namespace mbgl;
-using namespace std::chrono_literals;
 
 TEST(ActorRef, CanOutliveActor) {
     // An ActorRef can outlive its actor. Doing does not extend the actor's lifetime.
@@ -40,3 +37,58 @@ TEST(ActorRef, CanOutliveActor) {
     EXPECT_TRUE(died);
     test.invoke(&Test::receive);
 }
+
+TEST(ActorRef, Ask) {
+    // Ask returns a Future eventually returning the result
+
+    struct Test {
+
+        Test(ActorRef<Test>) {}
+
+        int gimme() {
+            return 20;
+        }
+
+        int echo(int i) {
+            return i;
+        }
+    };
+
+    ThreadPool pool { 1 };
+    Actor<Test> actor(pool);
+    ActorRef<Test> ref = actor.self();
+
+    EXPECT_EQ(20, ref.ask(&Test::gimme).get());
+    EXPECT_EQ(30, ref.ask(&Test::echo, 30).get());
+}
+
+
+TEST(ActorRef, AskOnDestroyedActor) {
+    // Tests behavior when calling ask() after the
+    // Actor has gone away. Should set a exception_ptr.
+
+    struct Test {
+        bool& died;
+
+        Test(ActorRef<Test>, bool& died_) : died(died_) {}
+
+        ~Test() {
+            died = true;
+        }
+
+        int receive() {
+            return 1;
+        }
+    };
+    bool died = false;
+
+    ThreadPool pool { 1 };
+    auto actor = std::make_unique<Actor<Test>>(pool, died);
+    ActorRef<Test> ref = actor->self();
+
+    actor.reset();
+    EXPECT_TRUE(died);
+
+    auto result = ref.ask(&Test::receive);
+    EXPECT_ANY_THROW(result.get());
+}