Unit Testing with multiple .cpp files

ATE-ENGE

Hello all,

I'm new to programming / QT and am trying to implement unit tests for my application. The application will have multiple classes and I would like to write unit tests to pair with these classes as well as the project as a whole. Looking at the forums and GPT example code, I understand I should have my project built like so:

Project.pro
Headers
--mainwindow.h
--src/
----class1.h
----class2.h
Sources
--mainwindow.cpp
--main.cpp
--src/
----class1.h
----class2.h
Forms
--mainwindow.ui
Other files
--tests/
----tst_class1
----tst_class2
----tst_class1and2

With my .pro file containing:

QT       += core gui testlib
CONFIG += c++17 testcase
SOURCES += \
    main.cpp \
    mainwindow.cpp \
    src/class1.cpp \
    src/class2.cpp \

HEADERS += \
    mainwindow.h \
    src/class1.h \
    src/class2.h \

FORMS += \
    mainwindow.ui

# Test sources
test1.sources = tests/tst_class1.cpp
test1.target = tst_class1
test1.CONFIG += console
test1.CONFIG += testcase

test2.sources = tests/tst_class2.cpp
test2.target = tst_class2
test2.CONFIG += console
test2.CONFIG += testcase

test3.sources = tests/tst_class1and2.cpp
test3.target = tst_class1and2
test3.CONFIG += console
test3.CONFIG += testcase

# Include the test sources in the project
OTHER_FILES += \
    tests/tst_class1.cpp \
    tests/tst_class2.cpp \
    tests/tst_class1and2.cpp

# Default rules for deployment.
qnx: target.path = /tmp/$${TARGET}/bin
else: unix:!android: target.path = /opt/$${TARGET}/bin
!isEmpty(target.path): INSTALLS += target

DISTFILES +=

I have each tst file containing

#include <QtTest>
#include "src/class1.h"

class TestStateMachine : public QObject {
    Q_OBJECT

private slots:
    void initTestCase();
    void test1A();
    void test1B();
    void cleanupTestCase();
};

[function definitions here]

QTEST_MAIN(TestStateMachine)
#include "tst_main.moc"

If possible there are two things I'd like to fix.

Most important although the program compiles, I understand that I'm supposed to see tst_class1.exe in my build folder and I do not, so I have no idea if the tests are being run or how to run them
I know QT has the display window "8 Test Results," with output that the provided example uses. Looking at help documents from ~2019, it looks like this won't populate if you have multiple test files (or the only way to have multiple test files subverts this window.) Is that still the case?

SGaist

Hi,

That is usually done using the SUBDIRS template where each test is its own project as is the application.

Often you will have a library project that contains your application business logic and that will also contain the tests and an app project that will make use of the library.

ATE-ENGE

@SGaist Fantastic! Thank you for letting me know. I'm looking at the wiki here (https://wiki.qt.io/SUBDIRS_-_handling_dependencies) and seeing the example:

/FooApp
   |--- Makefile
   |--- subdirs.pro
   |--- src
        |
        |--- app
        |    |--- app.pro
        |    |--- Makefile
        |    |--- Makefile.Debug
        |    |--- Makefile.Release
        |    `--- ... (source files of app)
        |--- lib
        |    |--- lib.pro
        |    |--- Makefile
        |    |--- Makefile.Debug
        |    |--- Makefile.Release
        |    `--- ... (source files of lib)
        |--- lib2
        |    |--- lib2.pro
        |    |--- Makefile
        |    |--- Makefile.Debug
        |    |--- Makefile.Release

For my project, would that then translate to?

/FooApp
   |--- Makefile
   |--- subdirs.pro
   |--- src
        |
        |--- app
        |    |--- app.pro
        |    |--- mainwindow.h 
        |    |--- mainwindow.cpp        
        |    |--- main.cpp
        |    |--- tst_class1and2
        |--- class 1
        |    |--- class1.pro
        |    |--- class1.h
        |    |--- class1.cpp
        |    |--- tst_class1.cpp
        |--- class2
        |     |--- class2.pro
        |     |--- class2.h
        |     |--- class2.cpp
        |     |--- tst_class2.cpp

SGaist

It would rather be something like:

/FooApp
   |--- subdirs.pro
   |--- src
        |
        |--- app
        |    |--- app.pro
        |    |--- appname
        |        |--- appname.pro 
        |        |--- mainwindow.h 
        |        |--- mainwindow.cpp        
        |        |--- main.cpp
        |    |--- tests
        |        |--- tests.pro
        |            |--- tst_mainwindow
        |               |--- tst_mainwindow.pro
        |               |--- tst_mainwindow.cpp
        |--- lib
        |    |--- lib.pro
        |.   |--- mylib
        |.       |--- mylib.pro
        |        |--- class1.h
        |        |--- class1.cpp
        |        |--- class2.h
        |        |--- class2.cpp
        |    |--- tests
        |        |--- tests.pro
        |            |--- tst_class1
        |               |--- tst_class1.pro
        |               |--- tst_class1.cpp
        |            |--- tst_class2
        |               |--- tst_class2.pro
        |               |--- tst_class2.cpp

You can check the Qt sources structure to make yourself an idea.

Note that since it's a new project, you might want to move to cmake as qmake is deprecated.

ATE-ENGE

Ok, I'll look to shift to cmake.
In terms of all those additional .pro files, How can I determine what should go in each?

SGaist

The "folders" .pro files are subdirs projects while the leaf .pro files are either app, libs or tests projects.

ATE-ENGE

Ok, with this structure I'm trying to build my tests/tst_class1/tst_class1.cpp However, I'm doing something wrong as my code is producing an unresolved external symbol error. I'm guessing I'm doing something wrong in the pro files.

lib.pro

TEMPLATE = subdirs

SUBDIRS += \
    mylib \
    tests

mylib.pro

QT += core gui sql network

CONFIG += c++17 cmdline testcase

# You can make your code fail to compile if it uses deprecated APIs.
# In order to do so, uncomment the following line.
#DEFINES += QT_DISABLE_DEPRECATED_BEFORE=0x060000    # disables all the APIs deprecated before Qt 6.0.0

SOURCES += \
        class1.cpp \
        main.cpp

HEADERS += \
    class1.h

# Default rules for deployment.
qnx: target.path = /tmp/$${TARGET}/bin
else: unix:!android: target.path = /opt/$${TARGET}/bin
!isEmpty(target.path): INSTALLS += target

tests.pro

TEMPLATE = subdirs

SUBDIRS += \
    tst_class1

tst_class1.pro

QT += core gui sql network testlib

CONFIG += c++17 cmdline testcase

# You can make your code fail to compile if it uses deprecated APIs.
# In order to do so, uncomment the following line.
#DEFINES += QT_DISABLE_DEPRECATED_BEFORE=0x060000    # disables all the APIs deprecated before Qt 6.0.0

SOURCES += \
    tst_class1.cpp \

INCLUDEPATH += ../../mylib/

# Default rules for deployment.
qnx: target.path = /tmp/$${TARGET}/bin
else: unix:!android: target.path = /opt/$${TARGET}/bin
!isEmpty(target.path): INSTALLS += target

Is there something I need to change?

SGaist

You are not linking against the library you are testing.