documentation/testing.sgml

   1   <chapter id="testing">
   2     <title>Writing Conformance tests</title>
   3
   4     <sect1 id="testing-intro">
   5       <title>Introduction</title>
   6       <para>
   7         The Windows API follows no standard, it is itself a de facto standard,
   8         and deviations from that standard, even small ones, often cause
   9         applications to crash or misbehave in some way.
  10       </para>
  11       <para>
  12         The question becomes, "How do we ensure compliance with that standard?"
  13         The answer is, "By using the API documentation available to us and
  14         backing that up with conformance tests." Furthermore, a conformance
  15         test suite is the most accurate (if not necessarily the most complete)
  16         form of API documentation and can be used to supplement the Windows
  17         API documentation.
  18       </para>
  19       <para>
  20         Writing a conformance test suite for more than 10000 APIs is no small
  21         undertaking. Fortunately it can prove very useful to the development
  22         of Wine way before it is complete.
  23         <itemizedlist>
  24           <listitem>
  25             <para>
  26               The conformance test suite must run on Windows. This is
  27               necessary to provide a reasonable way to verify its accuracy.
  28               Furthermore the tests must pass successfully on all Windows
  29               platforms (tests not relevant to a given platform should be
  30               skipped).
  31             </para>
  32             <para>
  33               A consequence of this is that the test suite will provide a
  34               great way to detect variations in the API between different
  35               Windows versions. For instance, this can provide insights
  36               into the differences between the, often undocumented, Win9x and
  37               NT Windows families.
  38             </para>
  39             <para>
  40               However, one must remember that the goal of Wine is to run
  41               Windows applications on Linux, not to be a clone of any specific
  42               Windows version. So such variations must only be tested for when
  43               relevant to that goal.
  44             </para>
  45           </listitem>
  46           <listitem>
  47             <para>
  48               Writing conformance tests is also an easy way to discover
  49               bugs in Wine. Of course, before fixing the bugs discovered in
  50               this way, one must first make sure that the new tests do pass
  51               successfully on at least one Windows 9x and one Windows NT
  52               version.
  53             </para>
  54             <para>
  55               Bugs discovered this way should also be easier to fix. Unlike
  56               some mysterious application crashes, when a conformance test
  57               fails, the expected behavior and APIs tested for are known thus
  58               greatly simplifying the diagnosis.
  59             </para>
  60           </listitem>
  61           <listitem>
  62             <para>
  63               To detect regressions. Simply running the test suite regularly
  64               in Wine turns it into a great tool to detect regressions.
  65               When a test fails, one immediately knows what was the expected
  66               behavior and which APIs are involved. Thus regressions caught
  67               this way should be detected earlier, because it is easy to run
  68               all tests on a regular basis, and be easier to fix because of the
  69               reduced diagnosis work.
  70             </para>
  71           </listitem>
  72           <listitem>
  73             <para>
  74               Tests written in advance of the Wine development (possibly even
  75               by non Wine developers) can also simplify the work of the
  76               future implementer by making it easier for him to check the
  77               correctness of his code.
  78             </para>
  79           </listitem>
  80           <listitem>
  81             <para>
  82               Conformance tests will also come in handy when testing Wine on
  83               new (or not as widely used) architectures such as FreeBSD,
  84               Solaris x86 or even non-x86 systems. Even when the port does
  85               not involve any significant change in the thread management,
  86               exception handling or other low-level aspects of Wine, new
  87               architectures can expose subtle bugs that can be hard to
  88               diagnose when debugging regular (complex) applications.
  89             </para>
  90           </listitem>
  91         </itemizedlist>
  92       </para>
  93     </sect1>
  94
  95
  96     <sect1 id="testing-what">
  97       <title>What to test for?</title>
  98       <para>
  99         The first thing to test for is the documented behavior of APIs
 100         and such as CreateFile. For instance one can create a file using a
 101         long pathname, check that the behavior is correct when the file
 102         already exists, try to open the file using the corresponding short
 103         pathname, convert the filename to Unicode and try to open it using
 104         CreateFileW, and all other things which are documented and that
 105         applications rely on.
 106       </para>
 107       <para>
 108         While the testing framework is not specifically geared towards this
 109         type of tests, it is also possible to test the behavior of Windows
 110         messages. To do so, create a window, preferably a hidden one so that
 111         it does not steal the focus when running the tests, and send messages
 112         to that window or to controls in that window. Then, in the message
 113         procedure, check that you receive the expected messages and with the
 114         correct parameters.
 115       </para>
 116       <para>
 117         For instance you could create an edit control and use WM_SETTEXT to
 118         set its contents, possibly check length restrictions, and verify the
 119         results using WM_GETTEXT. Similarly one could create a listbox and
 120         check the effect of LB_DELETESTRING on the list's number of items,
 121         selected items list, highlighted item, etc. For concrete examples,
 122         see <filename>dlls/user/tests/win.c</> and the related tests.
 123       </para>
 124       <para>
 125         However, undocumented behavior should not be tested for unless there
 126         is an application that relies on this behavior, and in that case the
 127         test should mention that application, or unless one can strongly
 128         expect applications to rely on this behavior, typically APIs that
 129         return the required buffer size when the buffer pointer is NULL.
 130       </para>
 131     </sect1>
 132
 133
 134     <sect1 id="testing-wine">
 135       <title>Running the tests in Wine</title>
 136       <para>
 137         The simplest way to run the tests in Wine is to type 'make test' in
 138         the Wine sources top level directory. This will run all the Wine
 139         conformance tests.
 140       </para>
 141       <para>
 142         The tests for a specific Wine library are located in a 'tests'
 143         directory in that library's directory. Each test is contained in a
 144         file (e.g. <filename>dlls/kernel/tests/thread.c</>). Each
 145         file itself contains many checks concerning one or more related APIs.
 146       </para>
 147       <para>
 148         So to run all the tests related to a given Wine library, go to the
 149         corresponding 'tests' directory and type 'make test'. This will
 150         compile the tests, run them, and create an '<replaceable>xxx</>.ok'
 151         file for each test that passes successfully. And if you only want to
 152         run the tests contained in the <filename>thread.c</> file of the
 153         kernel library, you would do:
 154 <screen>
 155 <prompt>$ </>cd dlls/kernel/tests
 156 <prompt>$ </>make thread.ok
 157 </screen>
 158       </para>
 159       <para>
 160         Note that if the test has already been run and is up to date (i.e. if
 161         neither the kernel library nor the <filename>thread.c</> file has
 162         changed since the <filename>thread.ok</> file was created), then make
 163         will say so. To force the test to be re-run, delete the
 164         <filename>thread.ok</> file, and run the make command again.
 165       </para>
 166       <para>
 167         You can also run tests manually using a command similar to the
 168         following:
 169 <screen>
 170 <prompt>$ </>../../../tools/runtest -q -M kernel32.dll -p kernel32_test.exe.so thread.c
 171 <prompt>$ </>../../../tools/runtest -P wine -p kernel32_test.exe.so thread.c
 172 thread.c: 86 tests executed, 5 marked as todo, 0 failures.
 173 </screen>
 174         The '-P wine' option defines the platform that is currently being
 175         tested and is used in conjunction with the 'todo' statements (see
 176         below). Remove the '-q' option if you want the testing framework
 177         to report statistics about the number of successful and failed tests.
 178         Run <command>runtest -h</> for more details.
 179       </para>
 180     </sect1>
 181
 182
 183     <sect1 id="cross-compiling-tests">
 184       <title>Cross-compiling the tests with MinGW</title>
 185       <sect2>
 186         <title>Setup of the MinGW cross-compiling environment</title>
 187         <para>
 188           Here are some instructions to setup MinGW on different Linux
 189           distributions and *BSD.
 190         </para>
 191         <sect3>
 192           <title>Debian GNU/Linux</title>
 193           <para>
 194             On Debian do <command>apt-get install mingw32</>.
 195           </para>
 196           <para>
 197             The standard MinGW libraries will probably be incomplete, causing
 198             'undefined symbol' errors. So get the latest
 199             <ulink url="http://mirzam.it.vu.nl/mingw/">mingw-w32api RPM</>
 200             and use <command>alien</> to either convert it to a .tar.gz file
 201             from which to extract just the relevant files, or to convert it
 202             to a Debian package that you will install.
 203           </para>
 204         </sect3>
 205         <sect3>
 206           <title>Red Hat Linux like rpm systems</title>
 207           <para>
 208             This includes Fedora Core, Red Hat Enterprise Linux, Mandrake,
 209             most probably SuSE Linux too, etc. But this list isn't exhaustive;
 210             the following steps should probably work on any rpm based system.
 211           </para>
 212           <para>
 213             Download and install the latest rpm's from
 214             <ulink url="http://mirzam.it.vu.nl/mingw/">MinGW RPM packages</>.
 215             Alternatively you can follow the instructions on that page and
 216             build your own packages from the source rpm's listed there as well.
 217           </para>
 218         </sect3>
 219         <sect3>
 220           <title>*BSD</title>
 221           <para>
 222             The *BSD systems have in their ports collection a port for the
 223             MinGW cross-compiling environment. Please see the documentation
 224             of your system about how to build and install a port.
 225           </para>
 226         </sect3>
 227       </sect2>
 228       <sect2>
 229       <title>Compiling the tests</title>
 230       <para>
 231         Having the cross-compiling environment set up the generation of the
 232         Windows executables is easy by using the Wine build system.
 233       </para>
 234       <para>
 235         If you had already run <command>configure</>, then delete
 236         <filename>config.cache</> and re-run <command>configure</>.
 237         You can then run <command>make crosstest</>. To sum up:
 238 <screen>
 239 <prompt>$ </><userinput>rm config.cache</>
 240 <prompt>$ </><userinput>./configure</>
 241 <prompt>$ </><userinput>make crosstest</>
 242 </screen>
 243       </para>
 244       </sect2>
 245     </sect1>
 246
 247
 248     <sect1 id="testing-windows">
 249       <title>Building and running the tests on Windows</title>
 250       <sect2>
 251         <title>Using pre-compiled binaries</title>
 252         <para>
 253           The simplest solution is to download the
 254           <ulink url="http://www.astro.gla.ac.uk/users/paulm/WRT/CrossBuilt/winetest-latest.exe">latest
 255           version of winetest</>. This executable contains all the Wine
 256           conformance tests, runs them and reports the results.
 257         </para>
 258         <para>
 259           You can also get the older versions from
 260           <ulink url="http://www.astro.gla.ac.uk/users/paulm/WRT/CrossBuilt/">Paul
 261           Millar's website</>.
 262         </para>
 263       </sect2>
 264       <sect2>
 265         <title>With Visual C++</title>
 266         <itemizedlist>
 267           <listitem><para>
 268             If you are using Visual Studio 6, make sure you have the
 269             "processor pack" from
 270             <ulink url="http://msdn.microsoft.com/vstudio/downloads/tools/ppack/default.aspx">http://msdn.microsoft.com/vstudio/downloads/tools/ppack/default.aspx</>.
 271             The processor pack fixes <emphasis>"error C2520: conversion from
 272             unsigned __int64 to double not implemented, use signed __int64"</>.
 273             However note that the "processor pack" is incompatible with
 274             Visual Studio 6.0 Standard Edition, and with the Visual Studio 6
 275             Service Pack 6. If you are using Visual Studio 7 or greater you
 276             do not need the processor pack. In either case it is recommended
 277             to the most recent compatible Visual Studio
 278             <ulink url="http://msdn.microsoft.com/vstudio/downloads/updates/sp/">service pack</>.
 279           </para></listitem>
 280           <listitem><para>
 281             get the Wine sources
 282           </para></listitem>
 283           <listitem><para>
 284             Run msvcmaker to generate Visual C++ project files for the tests.
 285             'msvcmaker' is a perl script so you may be able to run it on
 286             Windows.
 287 <screen>
 288 <prompt>$ </>./tools/winapi/msvcmaker --no-wine
 289 </screen>
 290           </para></listitem>
 291           <listitem><para>
 292             If the previous steps were done on your Linux development
 293             machine, make the Wine sources accessible to the Windows machine
 294             on which you are going to compile them. Typically you would do
 295             this using Samba but copying them altogether would work too.
 296           </para></listitem>
 297           <listitem><para>
 298             On the Windows machine, open the <filename>winetest.dsw</>
 299             workspace. This will load each test's project. For each test there
 300             are two configurations: one compiles the test with the Wine
 301             headers, and the other uses the Microsoft headers.
 302           </para></listitem>
 303           <listitem><para>
 304             If you choose the "Win32 MSVC Headers" configuration, most of the
 305             tests will not compile with the regular Visual Studio headers. So
 306             to use this configuration, download and install a recent
 307             <ulink url="http://www.microsoft.com/msdownload/platformsdk/sdkupdate/">Platform SDK</>
 308             (the download requires Internet Explorer!), as well as the latest
 309             <ulink url="http://msdn.microsoft.com/library/default.asp?url=/downloads/list/directx.asp">DirectX SDK</>.
 310             Then, <ulink url="http://msdn.microsoft.com/library/default.asp?url=/library/EN-US/sdkintro/sdkintro/installing_the_platform_sdk_with_visual_studio.asp">configure Visual Studio</>
 311             to use these SDK's headers and libraries. Alternately you could go
 312             to the <menuchoice><guimenu>Project</> <guimenu>Settings...</></>
 313             menu and modify the settings appropriately, but you would then
 314             have to redo this whenever you rerun msvcmaker.
 315           </para></listitem>
 316           <listitem><para>
 317             Open the <menuchoice><guimenu>Build</> <guimenu>Batch
 318             build...</></> menu and select the tests and build configurations
 319             you want to build. Then click on <guibutton>Build</>.
 320           </para></listitem>
 321           <listitem><para>
 322             To run a specific test from Visual C++, go to
 323             <menuchoice><guimenu>Project</> <guimenu>Settings...</></>. There
 324             select that test's project and build configuration and go to the
 325             <guilabel>Debug</> tab. There type the name of the specific test
 326             to run (e.g. 'thread') in the <guilabel>Program arguments</>
 327             field. Validate your change by clicking on <guibutton>Ok</> and
 328             start the test by clicking the red exclamation mark (or hitting
 329             'F5' or any other usual method).
 330           </para></listitem>
 331           <listitem><para>
 332             You can also run the tests from the command line. You will find
 333             them in either <filename>Output\Win32_Wine_Headers</> or
 334             <filename>Output\Win32_MSVC_Headers</> depending on the build
 335             method. So to run the kernel 'path' tests you would do:
 336 <screen>
 337 <prompt>C:\&gt;</>cd dlls\kernel\tests\Output\Win32_MSVC_Headers
 338 <prompt>C:\wine\dlls\kernel\tests\Output\Win32_MSVC_Headers&gt;</> kernel32_test path
 339 </screen>
 340           </para></listitem>
 341         </itemizedlist>
 342       </sect2>
 343       <sect2>
 344         <title>With MinGW</title>
 345         <para>
 346          Wine's build system already has support for building tests with a MinGW
 347          cross-compiler. See the section above called 'Setup of the MinGW
 348          cross-compiling environment' for instructions on how to set things up.
 349          When you have a MinGW environment installed all you need to do is rerun
 350          configure and it should detect the MinGW compiler and tools. Then run
 351          'make crosstest' to start building the tests.
 352         </para>
 353       </sect2>
 354     </sect1>
 355
 356
 357     <sect1 id="testing-test">
 358       <title>Inside a test</title>
 359
 360       <para>
 361         When writing new checks you can either modify an existing test file or
 362         add a new one. If your tests are related to the tests performed by an
 363         existing file, then add them to that file. Otherwise create a new .c
 364         file in the tests directory and add that file to the
 365         <varname>CTESTS</> variable in <filename>Makefile.in</>.
 366       </para>
 367       <para>
 368         A new test file will look something like the following:
 369 <screen>
 370 #include &lt;wine/test.h&gt;
 371 #include &lt;winbase.h&gt;
 372
 373 /* Maybe auxiliary functions and definitions here */
 374
 375 START_TEST(paths)
 376 {
 377    /* Write your checks there or put them in functions you will call from
 378     * there
 379     */
 380 }
 381 </screen>
 382       </para>
 383       <para>
 384         The test's entry point is the START_TEST section. This is where
 385         execution will start. You can put all your tests in that section but
 386         it may be better to split related checks in functions you will call
 387         from the START_TEST section. The parameter to START_TEST must match
 388         the name of the C file. So in the above example the C file would be
 389         called <filename>paths.c</>.
 390       </para>
 391       <para>
 392         Tests should start by including the <filename>wine/test.h</> header.
 393         This header will provide you access to all the testing framework
 394         functions. You can then include the windows header you need, but make
 395         sure to not include any Unix or Wine specific header: tests must
 396         compile on Windows.
 397       </para>
 398       <para>
 399         You can use <function>trace</> to print informational messages. Note
 400         that these messages will only be printed if 'runtest -v' is being used.
 401 <screen>
 402   trace("testing GlobalAddAtomA\n");
 403   trace("foo=%d\n",foo);
 404 </screen>
 405       </para>
 406       <para>
 407         Then just call functions and use <function>ok</> to make sure that
 408         they behaved as expected:
 409 <screen>
 410   ATOM atom = GlobalAddAtomA( "foobar" );
 411   ok( GlobalFindAtomA( "foobar" ) == atom, "could not find atom foobar\n" );
 412   ok( GlobalFindAtomA( "FOOBAR" ) == atom, "could not find atom FOOBAR\n" );
 413 </screen>
 414         The first parameter of <function>ok</> is an expression which must
 415         evaluate to true if the test was successful. The next parameter is a
 416         printf-compatible format string which is displayed in case the test
 417         failed, and the following optional parameters depend on the format
 418         string.
 419       </para>
 420     </sect1>
 421
 422     <sect1 id="testing-error-messages">
 423       <title>Writing good error messages</title>
 424       <para>
 425         The message that is printed when a test fails is
 426         <emphasis>extremely</> important.
 427       </para>
 428       <para>
 429         Someone will take your test, run it on a Windows platform that
 430         you don't have access to, and discover that it fails. They will then
 431         post an email with the output of the test, and in particular your
 432         error message. Someone, maybe you, will then have to figure out from
 433         this error message why the test failed.
 434       </para>
 435       <para>
 436         If the error message contains all the relevant information that will
 437         be easy. If not, then it will require modifying the test, finding
 438         someone to compile it on Windows, sending the modified version to the
 439         original tester and waiting for his reply. In other words, it will
 440         be long and painful.
 441       </para>
 442       <para>
 443         So how do you write a good error message? Let's start with an example
 444         of a bad error message:
 445 <screen>
 446     ok(GetThreadPriorityBoost(curthread,&amp;disabled)!=0,
 447        "GetThreadPriorityBoost Failed\n");
 448 </screen>
 449         This will yield:
 450 <screen>
 451 thread.c:123: Test failed: GetThreadPriorityBoost Failed
 452 </screen>
 453       </para>
 454       <para>
 455         Did you notice how the error message provides no information about
 456         why the test failed? We already know from the line number exactly
 457         which test failed. In fact the error message gives strictly no
 458         information that cannot already be obtained by reading the code. In
 459         other words it provides no more information than an empty string!
 460       </para>
 461       <para>
 462         Let's look at how to rewrite it:
 463 <screen>
 464     BOOL rc;
 465 ...
 466     rc=GetThreadPriorityBoost(curthread,&amp;disabled);
 467     ok(rc!=0 && disabled==0,"rc=%d error=%ld disabled=%d\n",
 468        rc,GetLastError(),disabled);
 469 </screen>
 470         This will yield:
 471 <screen>
 472 thread.c:123: Test failed: rc=0 error=120 disabled=0
 473 </screen>
 474       </para>
 475       <para>
 476         When receiving such a message, one would check the source, see that
 477         it's a call to GetThreadPriorityBoost, that the test failed not
 478         because the API returned the wrong value, but because it returned an
 479         error code. Furthermore we see that GetLastError() returned 120 which
 480         winerror.h defines as ERROR_CALL_NOT_IMPLEMENTED. So the source of
 481         the problem is obvious: this Windows platform (here Windows 98) does
 482         not support this API and thus the test must be modified to detect
 483         such a condition and skip the test.
 484       </para>
 485       <para>
 486         So a good error message should provide all the information which
 487         cannot be obtained by reading the source, typically the function
 488         return value, error codes, and any function output parameter. Even if
 489         more information is needed to fully understand a problem,
 490         systematically providing the above is easy and will help cut down the
 491         number of iterations required to get to a resolution.
 492       </para>
 493       <para>
 494         It may also be a good idea to dump items that may be hard to retrieve
 495         from the source, like the expected value in a test if it is the
 496         result of an earlier computation, or comes from a large array of test
 497         values (e.g. index 112 of _pTestStrA in vartest.c). In that respect,
 498         for some tests you may want to define a macro such as the following:
 499 <screen>
 500 #define eq(received, expected, label, type) \
 501         ok((received) == (expected), "%s: got " type " instead of " type "\n", (label),(received),(expected))
 502
 503 ...
 504
 505     eq( b, curr_val, "SPI_{GET,SET}BEEP", "%d" );
 506 </screen>
 507        </para>
 508     </sect1>
 509
 510
 511     <sect1 id="testing-platforms">
 512       <title>Handling platform issues</title>
 513       <para>
 514         Some checks may be written before they pass successfully in Wine.
 515         Without some mechanism, such checks would potentially generate
 516         hundred of known failures for months each time the tests are being run.
 517         This would make it hard to detect new failures caused by a regression.
 518         or to detect that a patch fixed a long standing issue.
 519       </para>
 520       <para>
 521         Thus the Wine testing framework has the concept of platforms and
 522         groups of checks can be declared as expected to fail on some of them.
 523         In the most common case, one would declare a group of tests as
 524         expected to fail in Wine. To do so, use the following construct:
 525 <screen>
 526 todo_wine {
 527     SetLastError( 0xdeadbeef );
 528     ok( GlobalAddAtomA(0) == 0 && GetLastError() == 0xdeadbeef, "failed to add atom 0\n" );
 529 }
 530 </screen>
 531         On Windows the above check would be performed normally, but on Wine it
 532         would be expected to fail, and not cause the failure of the whole
 533         test. However. If that check were to succeed in Wine, it would
 534         cause the test to fail, thus making it easy to detect when something
 535         has changed that fixes a bug. Also note that todo checks are accounted
 536         separately from regular checks so that the testing statistics remain
 537         meaningful. Finally, note that todo sections can be nested so that if
 538         a test only fails on the cygwin and reactos platforms, one would
 539         write:
 540 <screen>
 541 todo("cygwin") {
 542     todo("reactos") {
 543         ...
 544     }
 545 }
 546 </screen>
 547         <!-- FIXME: Would we really have platforms such as reactos, cygwin, freebsd & co? -->
 548         But specific platforms should not be nested inside a todo_wine section
 549         since that would be redundant.
 550       </para>
 551       <para>
 552         When writing tests you will also encounter differences between Windows
 553         9x and Windows NT platforms. Such differences should be treated
 554         differently from the platform issues mentioned above. In particular
 555         you should remember that the goal of Wine is not to be a clone of any
 556         specific Windows version but to run Windows applications on Unix.
 557       </para>
 558       <para>
 559         So, if an API returns a different error code on Windows 9x and
 560         Windows NT, your check should just verify that Wine returns one or
 561         the other:
 562 <screen>
 563 ok ( GetLastError() == WIN9X_ERROR || GetLastError() == NT_ERROR, ...);
 564 </screen>
 565       </para>
 566       <para>
 567         If an API is only present on some Windows platforms, then use
 568         LoadLibrary and GetProcAddress to check if it is implemented and
 569         invoke it. Remember, tests must run on all Windows platforms.
 570         Similarly, conformance tests should nor try to correlate the Windows
 571         version returned by GetVersion with whether given APIs are
 572         implemented or not. Again, the goal of Wine is to run Windows
 573         applications (which do not do such checks), and not be a clone of a
 574         specific Windows version.
 575       </para>
 576       <!--para>
 577         FIXME: What about checks that cause the process to crash due to a bug?
 578       </para-->
 579     </sect1>
 580
 581
 582 <!-- FIXME: Strategies for testing threads, testing network stuff,
 583  file handling... -->
 584
 585   </chapter>
 586
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