Qt Test Overview▲

Qt Test is a framework for unit testing Qt based applications and libraries. Qt Test provides all the functionality commonly found in unit testing frameworks as well as extensions for testing graphical user interfaces.

Qt Test is designed to ease the writing of unit tests for Qt based applications and libraries:

Feature

Details

Lightweight

Qt Test consists of about 6000 lines of code and 60 exported symbols.

Self-contained

Qt Test requires only a few symbols from the Qt Core module for non-gui testing.

Rapid testing

Qt Test needs no special test-runners; no special registration for tests.

Data-driven testing

A test can be executed multiple times with different test data.

Basic GUI testing

Qt Test offers functionality for mouse and keyboard simulation.

Benchmarking

Qt Test supports benchmarking and provides several measurement back-ends.

IDE friendly

Qt Test outputs messages that can be interpreted by Qt Creator, Visual Studio, and KDevelop.

Thread-safety

The error reporting is thread safe and atomic.

Type-safety

Extensive use of templates prevent errors introduced by implicit type casting.

Easily extendable

Custom types can easily be added to the test data and test output.

You can use a Qt Creator wizard to create a project that contains Qt tests and build and run them directly from Qt Creator. For more information, see Running Autotests.

Creating a Test▲

To create a test, subclass QObject and add one or more private slots to it. Each private slot is a test function in your test. QTest::qExec() can be used to execute all test functions in the test object.

In addition, you can define the following private slots that are not treated as test functions. When present, they will be executed by the testing framework and can be used to initialize and clean up either the entire test or the current test function.

  • initTestCase() will be called before the first test function is executed.

  • initTestCase_data() will be called to create a global test data table.

  • cleanupTestCase() will be called after the last test function was executed.

  • init() will be called before each test function is executed.

  • cleanup() will be called after every test function.

Use initTestCase() for preparing the test. Every test should leave the system in a usable state, so it can be run repeatedly. Cleanup operations should be handled in cleanupTestCase(), so they get run even if the test fails.

Use init() for preparing a test function. Every test function should leave the system in a usable state, so it can be run repeatedly. Cleanup operations should be handled in cleanup(), so they get run even if the test function fails and exits early.

Alternatively, you can use RAII (resource acquisition is initialization), with cleanup operations called in destructors, to ensure they happen when the test function returns and the object moves out of scope.

If initTestCase() fails, no test function will be executed. If init() fails, the following test function will not be executed, the test will proceed to the next test function.

Example:

 
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class MyFirstTest: public QObject
{
    Q_OBJECT

private:
    bool myCondition()
    {
        return true;
    }

private slots:
    void initTestCase()
    {
        qDebug("Called before everything else.");
    }

    void myFirstTest()
    {
        QVERIFY(true); // check that a condition is satisfied
        QCOMPARE(1, 1); // compare two values
    }

    void mySecondTest()
    {
        QVERIFY(myCondition());
        QVERIFY(1 != 2);
    }

    void cleanupTestCase()
    {
        qDebug("Called after myFirstTest and mySecondTest.");
    }
};

Finally, if the test class has a static public void initMain() method, it is called by the QTEST_MAIN macros before the QApplication object is instantiated. For example, this allows for setting application attributes like Qt::AA_DisableHighDpiScaling. This was added in 5.14.

For more examples, refer to the Qt Test Tutorial.

Building a Test▲

You can build an executable that contains one test class that typically tests one class of production code. However, usually you would want to test several classes in a project by running one command.

See Writing a Unit Test for a step by step explanation.

Building with CMake and CTest▲

You can use Building with CMake and CTest to create a test. CTest enables you to include or exclude tests based on a regular expression that is matched against the test name. You can further apply the LABELS property to a test and CTest can then include or exclude tests based on those labels. All labeled targets will be run when test target is called on the command line.

There are several other advantages with CMake. For example, the result of a test run can be published on a web server using CDash with virtually no effort.

CTest scales to very different unit test frameworks, and works out of the box with QTest.

The following is an example of a CMakeLists.txt file that specifies the project name and the language used (here, mytest and C++), the Qt modules required for building the test (Qt5Test), and the files that are included in the test (tst_mytest.cpp).

 
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project(mytest LANGUAGES CXX)

find_package(Qt5Test REQUIRED)

set(CMAKE_INCLUDE_CURRENT_DIR ON)

set(CMAKE_AUTOMOC ON)

enable_testing(true)

add_executable(mytest tst_mytest.cpp)
add_test(NAME mytest COMMAND mytest)

target_link_libraries(mytest PRIVATE Qt5::Test)

For more information about the options you have, see Build with CMake.

Building with qmake▲

If you are using qmake as your build tool, just add the following to your project file:

 
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QT += testlib

If you would like to run the test via make check, add the additional line:

 
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CONFIG += testcase

See the qmake manual for more information about make check.

Building with Other Tools▲

If you are using other build tools, make sure that you add the location of the Qt Test header files to your include path (usually include/QtTest under your Qt installation directory). If you are using a release build of Qt, link your test to the QtTest library. For debug builds, use QtTest_debug.

Qt Test Command Line Arguments▲

 

Syntax▲

The syntax to execute an autotest takes the following simple form:

 
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testname [options] [testfunctions[:testdata]]...

Substitute testname with the name of your executable. testfunctions can contain names of test functions to be executed. If no testfunctions are passed, all tests are run. If you append the name of an entry in testdata, the test function will be run only with that test data.

For example:

 
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/myTestDirectory$ testQString toUpper

Runs the test function called toUpper with all available test data.

 
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/myTestDirectory$ testQString toUpper toInt:zero

Runs the toUpper test function with all available test data, and the toInt test function with the test data called zero (if the specified test data doesn't exist, the associated test will fail).

 
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/myTestDirectory$ testMyWidget -vs -eventdelay 500

Runs the testMyWidget function test, outputs every signal emission and waits 500 milliseconds after each simulated mouse/keyboard event.

Options▲

 
Logging Options▲

The following command line options determine how test results are reported:

  • -o filename,format Writes output to the specified file, in the specified format (one of txt, xml, lightxml, xunitxml or tap). The special filename - may be used to log to standard output.

  • -o filename Writes output to the specified file.

  • -txt Outputs results in plain text.

  • -xml Outputs results as an XML document.

  • -lightxml Outputs results as a stream of XML tags.

  • -xunitxml Outputs results as an Xunit XML document.

  • -csv Outputs results as comma-separated values (CSV). This mode is only suitable for benchmarks, since it suppresses normal pass/fail messages.

  • -teamcity Outputs results in TeamCity format.

  • -tap Outputs results in Test Anything Protocol (TAP) format.

The first version of the -o option may be repeated in order to log test results in multiple formats, but no more than one instance of this option can log test results to standard output.

If the first version of the -o option is used, neither the second version of the -o option nor the -txt, -xml, -lightxml, -teamcity, -xunitxml or -tap options should be used.

If neither version of the -o option is used, test results will be logged to standard output. If no format option is used, test results will be logged in plain text.

Test Log Detail Options▲

The following command line options control how much detail is reported in test logs:

  • -silent Silent output; only shows fatal errors, test failures and minimal status messages.

  • -v1 Verbose output; shows when each test function is entered. (This option only affects plain text output.)

  • -v2 Extended verbose output; shows each QCOMPARE() and QVERIFY(). (This option affects all output formats and implies -v1 for plain text output.)

  • -vs Shows all signals that get emitted and the slot invocations resulting from those signals. (This option affects all output formats.)

Testing Options▲

The following command-line options influence how tests are run:

  • -functions Outputs all test functions available in the test, then quits.

  • -datatags Outputs all data tags available in the test. A global data tag is preceded by ' __global__ '.

  • -eventdelay ms If no delay is specified for keyboard or mouse simulation (QTest::keyClick(), QTest::mouseClick() etc.), the value from this parameter (in milliseconds) is substituted.

  • -keydelay ms Like -eventdelay, but only influences keyboard simulation and not mouse simulation.

  • -mousedelay ms Like -eventdelay, but only influences mouse simulation and not keyboard simulation.

  • -maxwarnings number Sets the maximum number of warnings to output. 0 for unlimited, defaults to 2000.

  • -nocrashhandler Disables the crash handler on Unix platforms. On Windows, it re-enables the Windows Error Reporting dialog, which is turned off by default. This is useful for debugging crashes.

  • -platform name This command line argument applies to all Qt applications, but might be especially useful in the context of auto-testing. By using the "offscreen" platform plugin (-platform offscreen) it's possible to have tests that use QWidget or QWindow run without showing anything on the screen. Currently the offscreen platform plugin is only fully supported on X11.

Benchmarking Options▲<