[lldb-dev] Is anyone using the gtest Xcode project?

Zachary Turner zturner at google.com
Sat Mar 14 10:20:19 PDT 2015

grep *.py files for test_with_dsym.  But a random example I'll pull from
the search results is

In it you'll see this:

    *@unittest2.skipUnless(sys.platform.startswith("darwin"), "requires
    @expectedFailureDarwin(16361880) # <rdar://problem/16361880>, we get
the result correctly, but fail to invoke the Summary formatter.
    def test_with_dsym(self):
        """Test calling std::String member function."""

    @expectedFailureFreeBSD('llvm.org/pr17807') # Fails on FreeBSD buildbot
    @expectedFailureGcc # llvm.org/pr14437, fails with GCC 4.6.3 and 4.7.2
    @expectedFailureIcc # llvm.org/pr14437, fails with ICC 13.1
    @expectedFailureDarwin(16361880) # <rdar://problem/16361880>, we get
the result correctly, but fail to invoke the Summary formatter.
    def test_with_dwarf(self):
        """Test calling std::String member function."""

The LLDB test runner considers any class which derives from TestBase to be
a "test case" (so ExprCommandCallFunctionTestCase from this file is a test
case), and for each test case, any member function whose name starts with
"test" to be a single test.  So in this case we've got
and ExprCommandCallFunctionTestCase.test_with_dwarf.  The first only runs
on darwin, the second runs on all platforms but is xfail'ed on FreeBSD,
GCC, ICC, and darwin

(I'm not sure what the @dsym_test and @dwarf_test annotations are for)

On Sat, Mar 14, 2015 at 10:05 AM Jonathan Roelofs <jonathan at codesourcery.com>

> On 3/13/15 9:10 PM, Zachary Turner wrote:
> >
> >
> > On Fri, Mar 13, 2015 at 4:01 PM Jonathan Roelofs
> > <jonathan at codesourcery.com <mailto:jonathan at codesourcery.com>> wrote:
> >
> >     +ddunbar
> >
> >     On 3/13/15 9:53 AM, jingham at apple.com <mailto:jingham at apple.com>
> wrote:
> >      >>> Depending on how different the different things are.  Compiler
> >     tests
> >      >>> tend to have input, output and some machine that converts the
> >     input to
> >      >>> the output.  That is one very particular model of testing.
> >     Debugger
> >      >>> tests need to do: get to stage 1, if that succeeded, get to
> >     stage 2,
> >      >>> if that succeeded, etc.  Plus there's generally substantial
> >     setup code
> >      >>> to get somewhere interesting, so while you are there you
> >     generally try
> >      >>> to test a bunch of similar things.  Plus, the tests often have
> >     points
> >      >>> where there are several success cases, but each one requires a
> >      >>> different "next action", stepping being the prime example of
> this.
> >      >>> These are very different models and I don't see that trying to
> >     smush
> >      >>> the two together would be a fruitful exercise.
> >
> >     I think LIT does make the assumption that one "test file" has one
> "test
> >     result". But this is a place where we could extend LIT a bit. I don't
> >     think it would be very painful.
> >
> >     For me, this would be very useful for a few of the big libc++abi
> tests,
> >     like the demangler one, as currently I have to #ifdef out a couple of
> >     the cases that can't possibly work on my platform. It would be much
> >     nicer if that particular test file outputted multiple test results of
> >     which I could XFAIL the ones I know won't ever work. (For anyone who
> is
> >     curious, the one that comes to mind needs the c99 %a printf format,
> >     which my libc doesn't have. It's a baremetal target, and binary size
> is
> >     really important).
> >
> >     How much actual benefit is there in having lots of results per test
> >     case, rather than having them all &&'d together to one result?
> >
> >     Out of curiosity, does lldb's existing testsuite allow you to run
> >     individual test results in test cases where there are more than one
> test
> >     result?
> >
> >
> >   I think I'm not following this line of discussion.  So it's possible
> > you and Jim are talking about different things here.
> I think that's the case... I was imagining the "logic of the test"
> something like this:
>    1) Set 5 breakpoints
>    2) Continue
>    3) Assert that the debugger stopped at the first breakpoint
>    4) Continue
>    5) Assert that the debugger stopped at the second breakpoint
>    6) etc.
> Reading Jim's description again, with the help of your speculative
> example, it sounds like the test logic itself isn't straightline
> code.... that's okay too. What I was speaking to is a perceived
> difference in what the "results" of running such a test are.
> In llvm, the assertions are CHECK lines. In libc++, the assertions are
> calls to `assert` from assert.h, as well as `static_assert`s. In both
> cases, failing any one of those checks in a test makes the whole test
> fail. For some reason I had the impression that in lldb there wasn't a
> single test result per *.py test. Perhaps that's not the case? Either
> way, what I want to emphasize is that LIT doesn't care about the "logic
> of the test", as long as there is one test result per test (and even
> that condition could be amended, if it would be useful for lldb).
> >
> > If I understand correctly (and maybe I don't), what Jim is saying is
> > that a debugger test might need to do something like:
> >
> > 1) Set 5 breakpoints
> > 2) Continue
> > 3) Depending on which breakpoint gets hit, take one of 5 possible "next"
> > actions.
> >
> > But I'm having trouble coming up with an example of why this might be
> > useful.  Jim, can you make this a little more concrete with a specific
> > example of a test that does this, how the test works, and what the
> > different success / failure cases are so we can be sure everyone is on
> > the same page?
> >
> > In the case of the libc++ abi tests, I'm not sure what is meant by
> > "multiple results per test case".  Do you mean (for example) you'd like
> > to be able to XFAIL individual run lines based on some condition?  If
> I think this means I should make the libc++abi example even more
> concrete.... In libc++/libc++abi tests, the "RUN" line is implicit
> (well, aside from the few ShTest tests ericwf has added recently). Every
> *.pass.cpp test is a file that the test harness knows it has to compile,
> run, and check its exit status. That being said,
> libcxxabi/test/test_demangle.pass.cpp has a huge array like this:
>        20 const char* cases[][2] =
>        21 {
>        22     {"_Z1A", "A"},
>        23     {"_Z1Av", "A()"},
>        24     {"_Z1A1B1C", "A(B, C)"},
>        25     {"_Z4testI1A1BE1Cv", "C test<A, B>()"},
>     snip
>     29594     {"_Zli2_xy", "operator\"\" _x(unsigned long long)"},
>     29595     {"_Z1fIiEDcT_", "decltype(auto) f<int>(int)"},
>     29596 };
> Then there's some logic in `main()` that runs, __cxa_demangle on
> `cases[i][0]`, and asserts that it's the same as `cases[i][1]`. If any
> of those assertions fail, the entire test is marked as failing, and no
> further lines in that array are verified. For the sake of discussion,
> let's call each of entries in `cases` a "subtest", and the entirety of
> test_demangle.pass.cpp a test.
> The sticky issue is that there are a few subtests in this test that
> don't make sense on various platforms, so currently, they are #ifdef'd
> out. If the LIT TestFormat and the tests themselves had a way to
> communicate that a subtest failed, but to continue running other
> subtests after that, then we could XFAIL these weird subtests individually.
> Keep in mind though that I'm not really advocating we go and change
> test_demangle.pass.cpp to suit that model, because #ifdef's work
> reasonably well there, and there are relatively few subtests that have
> these platform differences... That's just the first example of the
> test/subtest relationship that I could think of.
> > so, LLDB definitely needs that.  One example which LLDB uses almost
> > everywhere is that of running the same test with dSYM or DWARF debug
> > info.  On Apple platforms, tests generally need to run with both dSYM
> > and DWARF debug info (literally just repeat the same test twice), and on
> > non Apple platforms, only DWARF tests ever need to be run.  So there
> > would need to be a way to express this.
> Can you point me to an example of this?
> >
> > There are plenty of other one-off examples.  Debuggers have a lot of
> > platform specific code, and the different platforms support different
> > amounts of functionality (especially for things like Android / Windows
> > that are works in progress).  So we frequently have the need to have a
> > single test file which has, say 10 tests in it.  And specific tests can
> > be XFAILed or even disabled individually based on conditions (usually
> > which platform is running the test suite, but not always).
> --
> Jon Roelofs
> jonathan at codesourcery.com
> CodeSourcery / Mentor Embedded
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