QTest a connection from a private member

[wasawi2]

Dear all,

So I would like to test if a connection is successful or if a connection has been fired.
I have been looking at topics like:
qSignalSpy
connection with Qt::UniqueConnection
isSignalConnected

but my problem is that the connection is done from a private member of the class:

void myMainWindow::aFunctionToTest( )
{
	connect( aPrivateMember, &aClass::aSignal, this, &myMainWindow::aSlot);
}

Would there be any way to test this function in some way?

Thank you very much!
w

[JonB]

@jsulm said in QTest a connection from a private member:

You just need to make the test class friend

So as the OP is asking this does require the code being tested to be changed!

@wasawi2
Whichever way up you look at it, you will have to make a change to allow a private member to be accessed outside. Which is what private means (i.e. cannot access outside, unless you change that or put in friend) :)

[Axel Spoerl]

@wasawi2
You have to make the private member a private slot. Then it should work.

[wasawi2]

Thank you for your answer @Axel-Spoerl !
Could you please elaborate your answer?
I'm very sorry but I don´t understand what you mean...

Are you talking about modifying the code to test?
I would like not to have to modify the code to test. Although a minor modification might be possible...

[wasawi2]

Ideally i would like to test that the connection has been successful with something like this:
QVERIFY( false == QObject::connect(&myMainWindow_instance.aPrivateMember, aSignal, &aMainwindow_instance, aSlot, Qt::UniqueConnection) );

[Axel Spoerl]

Can you show the declaration of the method you want to test?

Probably it’s in the

private

Section of the header. A connection won’t work here. You have to put it in a

private slots

section.

[wasawi2]

the method is in the "public slots:"

[wasawi2]

but of course the so called "aPrivateMember" is under the "private:" section

[wasawi2]

Sorry actually the method I'm testing is under the public: section... maybe that is the problem...

[Axel Spoerl]

It needs to be a slot, no matter if private or public.

[wasawi2]

ok, let me see if I understand well.
so the following code does not work because the object "aPrivateMember" is actually private. if it was public the code actually works.

the test code

void MainWindowTest::init ( ){}
void MainWindowTest::cleanup ( ){}
void MainWindowTest::test_case ( )
{
	qwidget_instance = new QWidget(  );
	mainWindow_instance = new myMainWindow( qwidget_instance );

	mainWindow_instance->aFunctionToTest( );
	QCOMPARE( (bool) QObject::connect(mainWindow_instance->aPrivateMember, &aClass::aSignal, mainWindow_instance, &myMainWindow::aSlot, Qt::UniqueConnection), false  );
// the test passes if, and only if aPrivateMember was declared in the public section.
// if aPrivateMember is private the following compile error occurs:
// error: 'aClass* myMainWindow::aPrivateMember' is private within this context
}

QTEST_MAIN( MainWindowTest )

the code to test

.h
class myMainWindow: public QMainWindow
{
Q_OBJECT

public slots:
void aFunctionToTest ( );
void aSlot ( );

private:
aClass aPrivateMember;
};


.cpp
void myMainWindow::aFunctionToTest( )
{
	connect( aPrivateMember, &aClass::aSignal, this, &myMainWindow::aSlot);
}

So my question stays the same. Is it possible to test the success of the connection done in aFunctionToTest given that aPrivateMember is actually private?

Thank you so much for the patience!
I tried to be as clear as possible now.

And I'm pretty sure I must be missing something obvious.. but I cant see what it is...

[Axel Spoerl]

Ah, now I understand better.
The private member can’t be tested (called) in an external test class normally. It also can’t be invoked / connected, because it isn’t a slot.
So if you want to connect it, it has to be a slot. If you want to keep it private, you could befriend the test class.

[wasawi2]

I see.
So If i understand correctly without modifying the code to test there is no way to test the connection.

[jsulm]

@wasawi2 @Axel-Spoerl Actually with the Qt5 connect syntax you can connect methods and lambdas which are not declared as slots. So, it should be possible without code modification. You just need to make the test class friend, so it can access non-public members of the class being tested.

[JonB]

@jsulm said in QTest a connection from a private member:

You just need to make the test class friend

So as the OP is asking this does require the code being tested to be changed!

@wasawi2
Whichever way up you look at it, you will have to make a change to allow a private member to be accessed outside. Which is what private means (i.e. cannot access outside, unless you change that or put in friend) :)

[jsulm]

@JonB said in QTest a connection from a private member:

So as the OP is asking this does require the code being tested to be changed!

Well, yes. But it does not require to change the visibility of the class members/methods.

[JonB]

@jsulm
I absolutely concur, hence my:

[private] cannot access outside, unless you change that or put in friend

The point being to answer OP's

So If i understand correctly without modifying the code to test there is no way to test the connection.

They will have to make some change, which doubtless they were attempting to avoid. Just a heads-up.