Implement Device::TransitionTo() and test it

test/CMakeLists.txt

@@ -107,6 +107,7 @@ add_testsuite(Device
     device/_exceptions.cxx
     device/_error_state.cxx
     device/_signals.cxx
+    device/_transitions.cxx
 
     LINKS FairMQ
     DEPENDS testhelper_runTestDevice

test/device/_transitions.cxx

@@ -0,0 +1,58 @@
+/********************************************************************************
+ * Copyright (C) 2014-2018 GSI Helmholtzzentrum fuer Schwerionenforschung GmbH  *
+ *                                                                              *
+ *              This software is distributed under the terms of the             *
+ *              GNU Lesser General Public Licence (LGPL) version 3,             *
+ *                  copied verbatim in the file "LICENSE"                       *
+ ********************************************************************************/
+
+#include <FairMQDevice.h>
+
+#include <gtest/gtest.h>
+
+#include <vector>
+#include <thread>
+
+namespace
+{
+
+using namespace std;
+using namespace fair::mq;
+
+void transitionTo(const std::vector<State>& states, int numExpectedStates)
+{
+    FairMQDevice device;
+
+    thread t([&] {
+        for (const auto& s : states) {
+            device.TransitionTo(s);
+        }
+    });
+
+    int numStates = 0;
+
+    device.SubscribeToStateChange("testRunner", [&numStates](State /* state */) {
+        numStates++;
+    });
+
+    device.RunStateMachine();
+
+    if (t.joinable()) {
+        t.join();
+    }
+
+    LOG(info) << "expected " << numExpectedStates << ", encountered " << numStates << " states";
+    EXPECT_EQ(numStates, numExpectedStates);
+}
+
+TEST(Transitions, TransitionTo)
+{
+    transitionTo({State::Exiting}, 2);
+    transitionTo({State::InitializingDevice, State::Initialized, State::Exiting}, 6);
+    transitionTo({State::Initialized, State::Exiting}, 6);
+    transitionTo({State::DeviceReady, State::Bound, State::Running, State::Exiting}, 24);
+    transitionTo({State::Ready, State::Exiting}, 14);
+    transitionTo({State::Running, State::Exiting}, 16);
+}
+
+} // namespace