## New project structure for projects in Qt Creator with unit tests

Note: This is a new version of an earlier post, with a revised project structure.

Note 2: See this post for the same project structure using the even better Catch testing framework.

This post assumes that you are using a C++ testing framework such as UnitTest++. See this earlier post for some information on installing UnitTest++ on Ubuntu.

To get the most out UnitTest++ it is a good idea to integrate its output into the Qt Creator IDE. The way I have set this up in Qt Creator is with subprojects. One for the main project, which again is split into the app itself and a library, and one for the tests. In addition, I have a helper project file, named defaults.pri. The structure of the project is like this:

MyProject
├─ MyProject.pro
├─ defaults.pri
├─ app/
│  ├─ app.pro
│  └─ main.cpp
├─ src/
│  ├─ src.pro
│  └─ myclass.cpp
└─ tests/
├─ tests.pro
└─ main.cpp

An example project using this code structure has been posted on Github by Filip Sund. (Thanks to Filip for doing this!)

The main project file, MyProject.pro will now be based on a subdirs template, and may look like this:

TEMPLATE = subdirs
CONFIG+=ordered
SUBDIRS = \
src \
app \
tests
app.depends = src
tests.depends = src

The app.depends and tests.depends statements makes sure that the src project is compiled before the application and tests, because the src directory contains the library that will be used by both the app and the tests.

(Thanks to Will for noting that this works better for parallel builds with make -j 8 than my previous version only using CONFIG+=ordered. We should keep CONFIG+=ordered in there still, though, because depends doesn’t affect the order when using make install).

## defaults.pri

Each of the other .pro files will include defaults.pri to have all the headers available. defaults.pri contains the following:

INCLUDEPATH += $$PWD/src SRC_DIR =$$PWD

If the library, main program and tests use common libraries, it is very useful to have the defaults.pri define these dependencies too.

## ./src

In the src folder, I have myclass.cpp, which is the class that I want to use and test. The src.pro needs to compile to a library, so that it may be used both by app and tests, and could look something like this:

include(../defaults.pri)
CONFIG -= qt

TARGET = myapp
TEMPLATE = lib

SOURCES += myclass.cpp
HEADERS += myclass.h

What this class does is not so interesting, it could be anything. A simple example could be this header file:

#ifndef MYCLASS_H
#define MYCLASS_H

class MyClass {
public:
};

#endif // MYCLASS_H

With this accompaning source file:

#include "myclass.h"

double MyClass::addition(double a, double b) {
return a * b;
}

## ./app

I only have a main.cpp file in app, because the app is basically just something that uses everything in the src folder. It will depend on the shared compiled library from src, and app.pro would look something like this:

include(../defaults.pri)

TEMPLATE = app
CONFIG += console
CONFIG -= app_bundle
CONFIG -= qt

SOURCES += main.cpp

LIBS += -L../src -lmyapp

The main.cpp file could be a simple program that uses MyClass:

#include <myclass.h>
#include <iostream>

using namespace std;

int main()
{
return 0;
}

## ./tests

In the tests folder I have simply added a main.cpp which will run the tests. Then tests.pro has the following contents:

include(../defaults.pri)
TEMPLATE = app

CONFIG   += console
CONFIG   -= app_bundle
CONFIG   -= qt

SOURCES += main.cpp

LIBS += -lunittest++ -L../src -lmyapp

Which now links to the myapp library in addition to the unit tests.

The main.cpp in tests file which could contain the following, if we were to use UnitTest++ as our testing library:

#include <unittest++/UnitTest++.h>
#include <myclass.h>

TEST(MyMath) {
MyClass my;
}

int main()
{
return UnitTest::RunAllTests();
}

This test will fail because my implementation of MyClass::addition is completely wrong:

class MyClass {
public:
double addition(double a, double b) {
return a * b;
}
};

Note that I’m including MyClass by through <myclass.h> which is possible because of the INCLUDEPATH variable in defaults.pri.

This is hopefully all you’ll need to define a project that compiles a library, as well as tests and an application using the library.

## Deploy Qt applications for Mac OS X

This turned out to be really simple. I was trying to create a Mac OS X version of my game, Nanoparticles, and was having trouble with some flicker when running a QGraphicsView with OpenGL. The solution turned out to simply be to disable some style sheet settings that I didn’t need.

After this I wanted to create a nice .dmg file for easy deployment on Mac OS X. Thankfully, this process is not hard either. I found this through the Qt Documentation, but it is actually simpler than it seems thanks to the macdeployqt tool. This is mentioned on the page, but I decided to give a more thorough walk through on how to use the tool here:

2. In the build directory, run
macdeployqt yourappname.app -dmg

macdeployqt is found in the ~/Library/QtSDK/Desktop/Qt/474/gcc/bin folder (if that is where you installed Qt)

3. You should now have a nice yourappname.dmg file in the build directory. Open this up and check that your application runs from there.
4. If everything is working fine, you can do some prettifying of your .dmg file by opening it up using the Disk Utility and converting it to a Read/Write disk image.
5. Open your Read/Write disk image and create a shortcut to your Applications folder. This could either be done by dragging the Applications folder while holding the command key or by creating a symbolic link in terminal:
ln -s /Applications ./Applications
6. Edit the icon size, background image, etc. by clicking Command + J to open the View Options. Also, use View -> Hide Toolbar and Hide Sidebar to hide the excessive toolbars from the disk image.
7. Close the image and use Disk Utility to convert it back to a compressed disk image.