qt-creator/doc/qtcreatordev/src/plugin-tests.qdoc

// Copyright (C) 2023 The Qt Company Ltd.
// SPDX-License-Identifier: LicenseRef-Qt-Commercial OR GFDL-1.3-no-invariants-only

/*!
    \page plugin-tests.html
    \title Adding Tests

    There are two main ways of testing your plugin code:

    \list
        \li \l{Plugin Tests}
        \li \l{Auto Tests}
    \endlist

    Both have their specific use cases and setup, which is described in the
    following sections.

    \section1 Setting up CMake

    Before adding tests, prepare your build files. They need to look for the
    QtTest dependency and have a CMake option for building your plugin with
    tests:

    \snippet exampleplugin/CMakeLists.txt 5

    \section1 Plugin Tests

    Plugin tests are deeply integrated into your plugin and its
    interaction with \QC. To add a test for something that requires
    the infrastructure of \QC or your plugin to be set up, write a plugin
    test.

    Plugin tests are executed by starting \QC with the \c{-test <pluginname>}
    command-line argument. \QC then fully loads your plugin and all the plugins
    that it depends on, going through the normal \l{Plugin Life Cycle}. After
    your plugin and all dependencies are fully initialized, your tests are
    executed. Afterwards, \QC automatically closes. Therefore, your plugin
    tests have access to all exported functionality of all \QC plugins that
    your plugin depends on, like \c{Core::ICore}. Use QtTest's normal test
    macros, like \c{QVERIFY} or \c{QCOMPARE} to report your test's success or
    failure.

    To add plugin tests, add a QObject based class with private slots for your
    tests, and register it with \c{ExtensionSystem::IPlugin::addTest()} in your
    plugin's \l{ExtensionSystem::IPlugin::initialize()} method. Guard all test
    related code with a check for \c{WITH_TESTS}, to avoid shipping a binary
    release of your plugin with test functions.

    Include QtTest:

    \snippet exampleplugin/example.cpp test include

    Then implement the test functions:

    \snippet exampleplugin/example.cpp plugin tests

    Register your test in ExtensionSystem::IPlugin::initialize():

    \snippet exampleplugin/example.cpp register tests

    If you declared the test object in the source file, like in this example,
    also include the \c{.moc} file that is required for Qt's meta object
    compiler:

    \snippet exampleplugin/example.cpp include moc

    \section1 Auto Tests

    To add a test that does not depend on a running \QC infrastructure, use an
    auto test that lives independent of your plugin interface. Parsers are a
    common example, but you can test many things in this way if they have been
    written in a modular way.

    Even though your test does not live in your plugin interface,
    like with plugin tests, you can still link the test to libraries and also
    your plugin library itself, to avoid code duplication or duplicate
    compilation of code.

    In principle you can use any auto test framework,
    but QtTest is a simple one that integrates well with Qt, and is also used
    for the \l{plugin tests}{Plugin Tests}.

    To add your test, add the test's C++ file, and use \c{add_qtc_test} in your
    CMake file to add the test target. If your test uses your plugin library,
    add it as a dependency with \c{DEPENDS}.

    In the following example, the plugin exports a function \c{addOne}:

    \quotefile exampleplugin/examplefunctions.h

    And implements it in a source file:

    \snippet exampleplugin/example.cpp exported function

    The test is linked against the plugin library target with \c{DEPENDS}:

    \snippet exampleplugin/CMakeLists.txt 6

    The QtTest based test then includes the header from the plugin and
    tests the function:

    \quotefile exampleplugin/tst_mytest.cpp
*/