Add in post callback function to simulation

include/fschuetz04/simcpp20/simulation.hpp

@@ -63,6 +63,19 @@ template <typename Time = double> class simulation {
     schedule(ev, delay);
     return ev;
   }
+
+  /**
+   * Posts a callback to be executed after the delay.
+   * @param callback Callback to invoke, which has the following signature: `void callback()`.
+   * @param delay Delay before executing the callback. If default constructed, execute as soon as possible.
+   * @return New pending event.
+   */
+  event_type post(std::function<void()> callback, Time delay = Time{0}) {
+    auto ev = event();
+    ev.add_callback(callback);
+    schedule(ev, delay);
+    return ev;
+  }
 
   /**
    * @tparam Value Value type of the event.

tests/tests.cpp

@@ -167,3 +167,75 @@ TEST_CASE("all_of") {
     REQUIRE(finished);
   }
 }
+
+TEST_CASE("post event to simulation") {
+  simcpp20::simulation<> sim;
+
+  bool ran = false;
+  auto ev1 = sim.post([&ran]() { ran = true; });
+
+  sim.step();
+  REQUIRE(ran);
+  REQUIRE(ev1.processed());
+}
+
+TEST_CASE("post event ordering") {
+  simcpp20::simulation<> sim;
+
+  SECTION("between other pending events")
+  {
+    bool ran = false;
+
+    auto ev1 = sim.timeout(1);
+    auto ev2 = sim.post([&ran]() { ran = true; });
+
+    sim.step();
+    REQUIRE(ran);
+    REQUIRE(ev1.pending());
+    REQUIRE(ev2.processed());
+  }
+
+  SECTION("between multiple posted events")
+  {
+    bool ran1 = false;
+    bool ran2 = false;
+    bool ran3 = false;
+
+    auto ev1 = sim.post([&ran1]() { ran1 = true; });
+    auto ev2 = sim.post([&ran2]() { ran2 = true; });
+    auto ev3 = sim.post([&ran3]() { ran3 = true; });
+
+    sim.step();
+    REQUIRE(ran1);
+    REQUIRE_FALSE(ran2);
+    REQUIRE_FALSE(ran3);
+
+    sim.step();
+    REQUIRE(ran1);
+    REQUIRE(ran2);
+    REQUIRE_FALSE(ran3);
+
+    sim.step();
+    REQUIRE(ran1);
+    REQUIRE(ran2);
+    REQUIRE(ran3);
+  }
+}
+
+TEST_CASE("post event with delay to simulation") {
+  simcpp20::simulation<> sim;
+
+  bool ran1 = false;
+  bool ran2 = false;
+
+  auto ev1 = sim.post([&ran1]() { ran1 = true; }, 2.0);
+  auto ev2 = sim.post([&ran2]() { ran2 = true; }, 1.0);
+
+  sim.step();
+  REQUIRE_FALSE(ran1);
+  REQUIRE(ran2);
+
+  sim.step();
+  REQUIRE(ran1);
+  REQUIRE(ran2);
+}