wip #129: fix test after slight behavior change

Initially, devices are closed and hence there is an error message. It goes away shortly when the device got opened. The new behavior is according to specification.

tests/executables_src/testExceptionHandling.cc

@@ -193,14 +193,25 @@ BOOST_AUTO_TEST_CASE(testExceptionHandlingRead) {
   dev1.write<int>("MyModule/readBack.DUMMY_WRITEABLE", 42);
   dev2.write<int>("MyModule/readBack.DUMMY_WRITEABLE", 52);
 
-  // initially there should be no error set
+  // initially, devices are not opened but errors should be cleared once they are opened
   trigger.write();
+
+  do {
+    message1.readLatest();
+    status1.readLatest();
+  } while(status1 != 0 || std::string(message1) != "");
   BOOST_CHECK(!message1.readLatest());
   BOOST_CHECK(!status1.readLatest());
+
+  do {
+    message2.readLatest();
+    status2.readLatest();
+  } while(status2 != 0 || std::string(message2) != "");
+  BOOST_CHECK(!message2.readLatest());
+  BOOST_CHECK(!status2.readLatest());
+
   CHECK_TIMEOUT(readback1.readLatest(), 10000);
   CHECK_TIMEOUT(readback2.readLatest(), 10000);
-  BOOST_CHECK(static_cast<std::string>(message1) == "");
-  BOOST_CHECK(status1 == 0);
   BOOST_CHECK_EQUAL(readback1, 42);
   BOOST_CHECK_EQUAL(readback2, 52);
 
@@ -295,7 +306,21 @@ BOOST_AUTO_TEST_CASE(testExceptionHandlingWrite) {
 
   auto trigger = test.getScalar<int>("trigger");
 
-  // initially there should be no error set
+  // initially, devices are not opened but errors should be cleared once they are opened
+  do {
+    message1.readLatest();
+    status1.readLatest();
+  } while(status1 != 0 || std::string(message1) != "");
+  BOOST_CHECK(!message1.readLatest());
+  BOOST_CHECK(!status1.readLatest());
+
+  do {
+    message2.readLatest();
+    status2.readLatest();
+  } while(status2 != 0 || std::string(message2) != "");
+  BOOST_CHECK(!message2.readLatest());
+  BOOST_CHECK(!status2.readLatest());
+
   actuator1 = 29;
   actuator1.write();
   actuator2 = 39;