Using Boost Unit Test framework to perform unit test on C++\Qt code.
We are basically using BOOST_FIXTURE_TEST_CASE macro as shown in documentation. For each test we create an instance of QApplication to setup the event loop and enable the test code to use signals and slots.
Now we need to test whether a signal is emitted or not. Does anyone have any experience with this issue? The BOOST_FIXTURE_TEST_CASE generated class does not inlucde Q_OBJECT and does not derived from QObject which I guess would be a problem. Appreciate some input on this issue.
I'm working on a similar issue, but using gtest rather than the Boost Unit Test framework. While I don't have the answer yet I am making progress, here is what I know so far.
First of all, Qt does not like it when QApplication or QCoreApplication are generated outside of main. Also, QApplication applies to GUI classes of Qt, while QCoreApplication can be used for console only classes (like QTcpSocket which is what I am trying to test now). GUI stuff is not really testable, so anything you are testing should be written into a separate class. This will allow you to unit test your code without dealing with the GUI, and also let you use QCoreApplication.
The next step is to use QThread to spin up a thread that hosts the object you are trying to test. QThread has its own event loop that can be run by calling its exec() function.
Write your test cases to pull from QThread and you'll have an event loop that you can use for the signals and slots, which should make it much easier to determine if a signal was emitted. Without the event loop the signal will just sit there and do nothing, so there is no way to test if it was sent!