Qtest Private Slots

To write a C unit test with Qt you need to create a class which inherits from QObject and implements at least one private slot. Each private slot is an independent test. The simplest unit test class is something like this. Note: You need to include the QTest header and declare the test functions as private slots so the test framework finds and executes it. Then you need to implement the test function itself. The implementation could look like this. The QTest framework makes executing tests easy in that the code in the QTESTAPPLESSMAIN MACO, which takes a reference to the Test Class, will inspect the Test Class for any Private Slots and assume them to be Test Methods that it must execute. In addition, the private slots initTestCase, cleanupTestCase, init and cleanup are executed if they exist. See Creating a Test for more details. Optionally, the command line arguments argc and argv can be provided. For a list of recognized arguments, read Qt Test Command Line Arguments. In addition, there are four private slots that are nottreated as test functions. 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. InitTestCasewill be called before the first test function is executed.

Qt provides functional and convenient framework for automate tests. It’s easy to setup, since it does not require any third party libraries nor special configuration. It also contains special mechanisms for Qt specific testing, like signals and slots handling, anyway it’s also good for non-Qt C++ project.

Qt test Setup

The only one requirement is to have Qt installed. Then, open your test .pro file and add: QT += testlib. In the test .cpp file, include: #include <QtTest>;.

That’s all. You are able now to write your QT test cases. Pretty simple!

The need of data driven testing

Imagine you want to test a sorting function which takes as an argument the reference to vector of int and performs the sorting in place.

Of course it’s necessary to test it with many inputs. You could start with writing following code:

It’s a bit repetitive and the code size grows very fast with adding new data sets. Besides, if you need to modify the test case, you need to do the change n times, what may lead to some mistakes.

That’s where the data driven testing should be used.

Data driven tests with Qt

Data driven testing method allows you to create a test case with many various data sets without repeating the same code many times, or using loops.

To start with data driven testing, you need to define another private Q_SLOT with the name of the test function + “_data” postfix, like:

The sort_test_data() method contains the data passed to sort_test() method. The body of sort_test_data() needs following elements: first, use QTest::addColumn to define the parts of your data set. Here we need input vector of type vector of int and the result also of type vector of int. Then use QTest::newRow to fill the data sets with data; each row is separate data set.

After your data sets are prepared, you just need to load them into the test function and run the test. Use QFETCH macro to load the columns defined in sort_test_data() function. The syntax is:

This macro will create local variables with names equal to column names. Note that inside QFETCH macro you shall not use quotes around the column name. If you try to fetch data from not-existing column (wrong column name), the test will assert.

This is how we created readable, easy to modify test with many various data sets. Above method will run QCOMPARE for every data set from sort_test_data function.

Custom data types

If you want to run the Qt data driven tests with the custom types, you can receive an error: Type is not registered, please use the Q_DECLARE_METATYPE macro to make it known to Qt’s meta-object system. The solution is already given in the message. You just need to add this macro into the header of your custom class. The macro should be outside the namespace, just like presented in below CFoo example:

Test results

The results exactly show which check with which data set failed or succeeded:

You can check out my github repository to take a look on the project with QT tests. The applied project structure was created with help of dragly.org post (projects in QtCreator with unit tests) and modified for my needs.

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:

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:

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).

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:

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

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:

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:

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

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).

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:

• -ofilename,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.
• -ofilename
  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

Qtest Private Slots Casino

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__ '.
• -eventdelayms
  If no delay is specified for keyboard or mouse simulation (QTest::keyClick(), QTest::mouseClick() etc.), the value from this parameter (in milliseconds) is substituted.
• -keydelayms
  Like -eventdelay, but only influences keyboard simulation and not mouse simulation.
• -mousedelayms
  Like -eventdelay, but only influences mouse simulation and not keyboard simulation.
• -maxwarningsnumber
  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.
• -platformname
  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

The following command line options control benchmark testing:

• -callgrind
  Uses Callgrind to time benchmarks (Linux only).
• -tickcounter
  Uses CPU tick counters to time benchmarks.
• -eventcounter
  Counts events received during benchmarks.
• -minimumvaluen
  Sets the minimum acceptable measurement value.
• -minimumtotaln
  Sets the minimum acceptable total for repeated executions of a test function.
• -iterationsn
  Sets the number of accumulation iterations.
• -mediann
  Sets the number of median iterations.
• -vb
  Outputs verbose benchmarking information.

Miscellaneous Options

• -help
  Outputs the possible command line arguments and gives some useful help.

Creating a Benchmark

To create a benchmark, follow the instructions for creating a test and then add a QBENCHMARK macro or QTest::setBenchmarkResult() to the test function that you want to benchmark. In the following code snippet, the macro is used:

A test function that measures performance should contain either a single QBENCHMARK macro or a single call to setBenchmarkResult(). Multiple occurrences make no sense, because only one performance result can be reported per test function, or per data tag in a>Walltime(default)All platformsCPU tick counter-tickcounterWindows, macOS, Linux, many UNIX-like systems.Event Counter-eventcounterAll platformsValgrind Callgrind-callgrindLinux (if installed)Linux Perf-perfLinux

In short, walltime is always available but requires many repetitions to get a useful result. Tick counters are usually available and can provide results with fewer repetitions, but can be susceptible to CPU frequency scaling issues. Valgrind provides exact results, but does not take I/O waits into account, and is only available on a limited number of platforms. Event counting is available on all platforms and it provides the number of events that were received by the event loop before they are sent to their corresponding targets (this might include non-Qt events).

The Linux Performance Monitoring solution is available only on Linux and provides many different counters, which can be selected by passing an additional option -perfcounter countername, such as -perfcounter cache-misses, -perfcounter branch-misses, or -perfcounter l1d-load-misses. The default counter is cpu-cycles. The full list of counters can be obtained by running any benchmark executable with the option -perfcounterlist.

• Using the performance counter may require enabling access to non-privileged applications.
• Devices that do not support high-resolution timers default to one-millisecond granularity.

Qtest Private Slots Online

See Writing a Benchmark in the Qt Test Tutorial for more benchmarking examples.

Qtest Private Slots Games

Using Global Test Data

You can define initTestCase_data() to set up a global test data table. Each test is run once for each row in the global test data table. When the test function itself is data-driven, it is run for each local data row, for each global data row. So, if there are g rows in the global data table and d rows in the test's own data-table, the number of runs of this test is g times d.

Global data is fetched from the table using the QFETCH_GLOBAL() macro.

The following are typical use cases for global test data:

• Selecting among the available database backends in QSql tests to run every test against every database.
• Doing all networking tests with and without SSL (HTTP versus HTTPS) and proxying.
• Testing a timer with a high precision clock and with a coarse one.
• Selecting whether a parser shall read from a QByteArray or from a QIODevice.

For example, to test each number provided by roundTripInt_data() with each locale provided by initTestCase_data():

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