source: trunk/doc/src/development/qtestlib.qdoc@ 788

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/*!
    \page qtestlib-manual.html
    \title QTestLib Manual
    \brief An overview of Qt's unit testing framework.

    \ingroup frameworks-technologies
    \keyword qtestlib

    The QTestLib framework, provided by Nokia, is a tool for unit
    testing Qt based applications and libraries. QTestLib provides
    all the functionality commonly found in unit testing frameworks as
    well as extensions for testing graphical user interfaces.

    Table of contents:

    \tableofcontents

    \section1 QTestLib Features

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

    \table
    \header \o Feature \o Details
    \row
        \o \bold Lightweight
        \o QTestLib consists of about 6000 lines of code and 60
           exported symbols.
    \row
        \o \bold Self-contained
        \o QTestLib requires only a few symbols from the Qt Core library
           for non-gui testing.
    \row
        \o \bold {Rapid testing}
        \o QTestLib needs no special test-runners; no special
           registration for tests.
    \row
        \o \bold {Data-driven testing}
        \o A test can be executed multiple times with different test data.
    \row
        \o \bold {Basic GUI testing}
        \o QTestLib offers functionality for mouse and keyboard simulation.
    \row
        \o \bold {Benchmarking}
        \o QTestLib supports benchmarking and provides several measurement back-ends.
    \row
         \o \bold {IDE friendly}
         \o QTestLib outputs messages that can be interpreted by Visual
            Studio and KDevelop.
    \row
         \o \bold Thread-safety
         \o The error reporting is thread safe and atomic.
    \row
         \o \bold Type-safety
         \o Extensive use of templates prevent errors introduced by
            implicit type casting.
    \row
         \o \bold {Easily extendable}
         \o Custom types can easily be added to the test data and test output.
    \endtable

    Note: For higher-level GUI and application testing needs, please
    see the \l{Third-Party Tools}{Qt testing products provided by
    Nokia partners}.


    \section1 QTestLib API

    All public methods are in the \l QTest namespace. In addition, the
    \l QSignalSpy class provides easy introspection for Qt's signals and slots.


    \section1 Using QTestLib

    \section2 Creating a Test

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

    In addition, there are four private slots that are \e not treated as testfunctions.
    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.

    \list
    \o \c{initTestCase()} will be called before the first testfunction is executed.
    \o \c{cleanupTestCase()} will be called after the last testfunction was executed.
    \o \c{init()} will be called before each testfunction is executed.
    \o \c{cleanup()} will be called after every testfunction.
    \endlist

    If \c{initTestCase()} fails, no testfunction will be executed. If \c{init()} fails,
    the following testfunction will not be executed, the test will proceed to the next
    testfunction.

    Example:
    \snippet doc/src/snippets/code/doc_src_qtestlib.qdoc 0

    For more examples, refer to the \l{QTestLib Tutorial}.

    \section2 Building a Test

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

    \snippet doc/src/snippets/code/doc_src_qtestlib.qdoc 1

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

    See \l {Chapter 1: Writing a Unit Test}{Writing a Unit Test} for a step by
    step explanation.

    \section2 QTestLib Command Line Arguments

    \section3 Syntax

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

    \snippet doc/src/snippets/code/doc_src_qtestlib.qdoc 2

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

    For example:

    \snippet doc/src/snippets/code/doc_src_qtestlib.qdoc 3

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

    \snippet doc/src/snippets/code/doc_src_qtestlib.qdoc 4

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

    \snippet doc/src/snippets/code/doc_src_qtestlib.qdoc 5

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

    \section3 Options

    The following command line arguments are understood:

    \list
    \o \c -help \BR
    outputs the possible command line arguments and give some useful help.
    \o \c -functions \BR
    outputs all test functions available in the test.
    \o \c -o \e filename \BR
    write output to the specified file, rather than to standard output
    \o \c -silent \BR
    silent output, only shows warnings, failures and minimal status messages
    \o \c -v1 \BR
    verbose output; outputs information on entering and exiting test functions.
    \o \c -v2 \BR
    extended verbose output; also outputs each \l QCOMPARE() and \l QVERIFY()
    \o \c -vs \BR
    outputs every signal that gets emitted
    \o \c -xml \BR
    outputs XML formatted results instead of plain text
    \o \c -lightxml \BR
    outputs results as a stream of XML tags
    \o \c -eventdelay \e ms \BR
    if no delay is specified for keyboard or mouse simulation
    (\l QTest::keyClick(),
    \l QTest::mouseClick() etc.), the value from this parameter
    (in milliseconds) is substituted.
    \o \c -keydelay \e ms \BR
    like -eventdelay, but only influences keyboard simulation and not mouse
    simulation.
    \o \c -mousedelay \e ms \BR
    like -eventdelay, but only influences mouse simulation and not keyboard
    simulation.
    \o \c -keyevent-verbose \BR
    output more verbose output for keyboard simulation
    \o \c -maxwarnings \e number\BR
    sets the maximum number of warnings to output. 0 for unlimited, defaults to 2000.
    \endlist

    \section2 Creating a Benchmark
    
    To create a benchmark, follow the instructions for crating a test and then add a
    QBENCHMARK macro to the test function that you want to benchmark.
    
    \snippet doc/src/snippets/code/doc_src_qtestlib.qdoc 12
    
    The code insde the QBENCHMARK macro will be measured, and possibly also repeated
    several times in order to get an accurate measurement. This depends on the selected
    measurement back-end. Several back-ends are available. They can be selected on the
    command line:
    
    \target testlib-benchmarking-measurement

    \table
    \header \o Name
         \o Commmand-line Argument
         \o Availability
    \row \o Walltime
         \o (default)
         \o All platforms
    \row \o CPU tick counter
         \o -tickcounter
         \o Windows, Mac OS X, Linux, many UNIX-like systems.
    \row \o Valgrind/Callgrind
         \o -callgrind
         \o Linux (if installed)
    \row \o Event Counter
         \o -eventcounter
         \o All platforms
    \endtable
    
    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).
       
    \note Depending on the device configuration, Tick counters on the
     Windows CE platform may not be as fine-grained, compared to other platforms.
     Devices that do not support high-resolution timers default to
     one-millisecond granularity.

    See the chapter 5 in the \l{QTestLib Tutorial} for more benchmarking examples.

    \section1 Using QTestLib remotely on Windows CE
    \c cetest is a convenience application which helps the user to launch an 
    application remotely on a Windows CE device or emulator.

    It needs to be executed after the unit test has been successfully compiled.

    Prior to launching, the following files are copied to the device:

    \list
    \o all Qt libraries the project links to
    \o \l {QtRemote}{QtRemote.dll}
    \o the c runtime library specified during installation
    \o all files specified in the \c .pro file following the \l DEPLOYMENT rules.
    \endlist

    \section2 Using \c cetest
    \section3 Syntax
    The syntax to execute an autotest takes the following simple form:

    \snippet doc/src/snippets/code/doc_src_qtestlib.qdoc 6

    \section3 Options
    \c cetest provides the same options as those for unit-testing on non cross-compiled
    platforms. See \l {QTestLib Command Line Arguments} {Command Line Arguments} for
    more information.

    The following commands are also included:

    \list
    \o \c -debug \BR
    Test version compiled in debug mode.
    \o \c -release \BR
    Test version compiled in release mode.
    \o \c -libpath \e path \BR
    Target path to copy Qt libraries to.
    \o \c -qt-delete \BR
    Delete Qt libraries after execution.
    \o \c -project-delete \BR
    Delete project files after execution.
    \o \c -delete \BR
    Delete project and Qt libraries after execution.
    \o \c -conf \BR
    Specifies a qt.conf file to be deployed to remote directory.
    \endlist

    \note \c{debug} is the default build option.

    \section2 QtRemote
    \c QtRemote is a small library which is build after QTestLib. It allows the host
    system to create a process on a remote device and waits until its execution has
    been finished.

    \section2 Requirements
    \c cetest uses Microsoft ActiveSync to establish a remote connection between the
    host computer and the device. Thus header files and libraries are needed to compile
    cetest and QtRemote successfully.

    Prior to \l{Installing Qt on Windows CE}{installation} of Qt, you need to set your
    \c INCLUDE and \c LIB environment variables properly.

    A default installation of Windows Mobile 5 for Pocket PC can be obtained by:

    \snippet doc/src/snippets/code/doc_src_qtestlib.qdoc 7

    Note that Qt will remember the path, so you do not need to set it again
    after switching the environments for cross-compilation.

    \section1 3rd Party Code

    The CPU tick counters used for benchmarking is licensed under the following
    license: (from src/testlib/3rdparty/cycle.h)
                    
    \legalese
    Copyright (c) 2003, 2006 Matteo Frigo\br
    Copyright (c) 2003, 2006 Massachusetts Institute of Technology