mirror of https://gitee.com/openkylin/libvirt.git
172 lines
6.4 KiB
ReStructuredText
172 lines
6.4 KiB
ReStructuredText
=========================
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Advanced test suite usage
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=========================
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The basic requirement before submitting changes to libvirt is that
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::
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$ ninja test
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succeed after each commit.
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The libvirt test suite, however, support additional features: for
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example, it's possible to look for memory leaks and similar issues
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by running
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::
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$ meson test --setup valgrind --suite bin
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`Valgrind <https://valgrind.org/>`__ is a test that checks for
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memory management issues, such as leaks or use of uninitialized
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variables.
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Some tests are skipped by default in a development environment,
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based on the time they take in comparison to the likelihood
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that those tests will turn up problems during incremental
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builds. These tests default to being run when building from a
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tarball or with the configure option -Dexpensive_tests=enabled.
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If you encounter any failing tests, the VIR_TEST_DEBUG
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environment variable may provide extra information to debug the
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failures. Larger values of VIR_TEST_DEBUG may provide larger
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amounts of information:
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::
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$ VIR_TEST_DEBUG=1 ninja test (or)
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$ VIR_TEST_DEBUG=2 ninja test
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When debugging failures during development, it is possible to
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focus in on just the failing subtests by using VIR_TEST_RANGE.
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I.e. to run all tests from 3 to 20 with the exception of tests
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6 and 16, use:
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::
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$ VIR_TEST_DEBUG=1 VIR_TEST_RANGE=3-5,7-20,^16 ./run tests/qemuxmlconftest
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Also, individual tests can be run from inside the ``tests/``
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directory, like:
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::
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$ ./qemuxmlconftest
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If you are adding new test cases, or making changes that alter
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existing test output, you can use the environment variable
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VIR_TEST_REGENERATE_OUTPUT to quickly update the saved test
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data. Of course you still need to review the changes VERY
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CAREFULLY to ensure they are correct.
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::
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$ VIR_TEST_REGENERATE_OUTPUT=1 ./qemuxmlconftest
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There is also a ``./run`` script at the top level, to make it
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easier to run programs that have not yet been installed, as
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well as to wrap invocations of various tests under gdb or
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Valgrind.
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When running our test suite it may happen that the test result
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is nondeterministic because of the test suite relying on a
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particular file in the system being accessible or having some
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specific value. To catch this kind of errors, the test suite
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has a module for that prints any path touched that fulfils
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constraints described above into a file. To enable it just set
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``VIR_TEST_FILE_ACCESS`` environment variable. Then
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``VIR_TEST_FILE_ACCESS_OUTPUT`` environment variable can alter
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location where the file is stored.
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::
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$ VIR_TEST_FILE_ACCESS=1 VIR_TEST_FILE_ACCESS_OUTPUT="/tmp/file_access.txt" ./qemuxmlconftest
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#. The Valgrind test should produce similar output to
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``ninja test``. If the output has traces within libvirt API's,
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then investigation is required in order to determine the cause
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of the issue. Output such as the following indicates some sort
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of leak:
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::
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==5414== 4 bytes in 1 blocks are definitely lost in loss record 3 of 89
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==5414== at 0x4A0881C: malloc (vg_replace_malloc.c:270)
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==5414== by 0x34DE0AAB85: xmlStrndup (in /usr/lib64/libxml2.so.2.7.8)
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==5414== by 0x4CC97A6: virDomainVideoDefParseXML (domain_conf.c:7410)
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==5414== by 0x4CD581D: virDomainDefParseXML (domain_conf.c:10188)
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==5414== by 0x4CD8C73: virDomainDefParseNode (domain_conf.c:10640)
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==5414== by 0x4CD8DDB: virDomainDefParse (domain_conf.c:10590)
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==5414== by 0x41CB1D: testCompareXMLToArgvHelper (qemuxmlconftest.c:100)
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==5414== by 0x41E20F: virtTestRun (testutils.c:161)
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==5414== by 0x41C7CB: mymain (qemuxmlconftest.c:866)
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==5414== by 0x41E84A: virtTestMain (testutils.c:723)
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==5414== by 0x34D9021734: (below main) (in /usr/lib64/libc-2.15.so)
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In this example, the ``virDomainDefParseXML()`` had an error
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path where the ``virDomainVideoDef *video`` pointer was not
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properly disposed. By simply adding a
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``virDomainVideoDefFree(video);`` in the error path, the issue
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was resolved.
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Another common mistake is calling a printing function, such as
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``VIR_DEBUG()`` without initializing a variable to be printed.
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The following example involved a call which could return an
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error, but not set variables passed by reference to the call.
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The solution was to initialize the variables prior to the call.
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::
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==4749== Use of uninitialised value of size 8
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==4749== at 0x34D904650B: _itoa_word (in /usr/lib64/libc-2.15.so)
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==4749== by 0x34D9049118: vfprintf (in /usr/lib64/libc-2.15.so)
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==4749== by 0x34D9108F60: __vasprintf_chk (in /usr/lib64/libc-2.15.so)
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==4749== by 0x4CAEEF7: virVasprintf (stdio2.h:199)
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==4749== by 0x4C8A55E: virLogVMessage (virlog.c:814)
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==4749== by 0x4C8AA96: virLogMessage (virlog.c:751)
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==4749== by 0x4DA0056: virNetTLSContextCheckCertKeyUsage (virnettlscontext.c:225)
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==4749== by 0x4DA06DB: virNetTLSContextCheckCert (virnettlscontext.c:439)
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==4749== by 0x4DA1620: virNetTLSContextNew (virnettlscontext.c:562)
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==4749== by 0x4DA26FC: virNetTLSContextNewServer (virnettlscontext.c:927)
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==4749== by 0x409C39: testTLSContextInit (virnettlscontexttest.c:467)
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==4749== by 0x40AB8F: virtTestRun (testutils.c:161)
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Valgrind will also find some false positives or code paths
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which cannot be resolved by making changes to the libvirt code.
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For these paths, it is possible to add a filter to avoid the
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errors. For example:
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::
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==4643== 7 bytes in 1 blocks are possibly lost in loss record 4 of 20
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==4643== at 0x4A0881C: malloc (vg_replace_malloc.c:270)
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==4643== by 0x34D90853F1: strdup (in /usr/lib64/libc-2.15.so)
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==4643== by 0x34EEC2C08A: ??? (in /usr/lib64/libnl.so.1.1)
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==4643== by 0x34EEC15B81: ??? (in /usr/lib64/libnl.so.1.1)
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==4643== by 0x34D8C0EE15: call_init.part.0 (in /usr/lib64/ld-2.15.so)
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==4643== by 0x34D8C0EECF: _dl_init (in /usr/lib64/ld-2.15.so)
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==4643== by 0x34D8C01569: ??? (in /usr/lib64/ld-2.15.so)
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In this instance, it is acceptable to modify the
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``tests/.valgrind.supp`` file in order to add a suppression
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filter. The filter should be unique enough to not suppress real
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leaks, but it should be generic enough to cover multiple code
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paths. The format of the entry can be found in the
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documentation found at the `Valgrind home
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page <https://valgrind.org/>`__. The following trace was added
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to ``tests/.valgrind.supp`` in order to suppress the warning:
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::
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{
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dlInitMemoryLeak1
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Memcheck:Leak
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fun:?alloc
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...
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fun:call_init.part.0
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fun:_dl_init
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...
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obj:*/lib*/ld-2.*so*
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}
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