[Lldb-commits] [PATCH] D37923: Implement interactive command interruption

[Zachary Turner via lldb-commits]

Also, it avoids polluting the SB interface with another function that
probably nobody is ever going to use outside of testing.  Adding to the SB
API should take an act of God, given that once it gets added it has to stay
until the end of time.

On Tue, Sep 19, 2017 at 11:15 AM Zachary Turner <zturner at google.com> wrote:

> That would work, but I think it's adding many more pieces to the test.
> Now there's threads, a Python layer, and multiprocess dotest infrastructure
> in the equation.  Each providing an additional source of flakiness and
> instability.
>
> If all it is is a pass-through, then just calling the function it passes
> through to is a strictly better test, since it's focusing the test on the
> underlying piece of functionality and removing additional sources of
> failure and instability from the test.
>
> On Tue, Sep 19, 2017 at 11:02 AM Jim Ingham <jingham at apple.com> wrote:
>
>> I'd really prefer to do this as/along with an SB API test since we also
>> need commands made through the SB API to be interruptible, and we should
>> test that that also works.  So this kills two birds with one stone.
>>
>> In general, when developing any high-level features in lldb one of the
>> questions you should ask yourself is whether this is useful at the SB API
>> layer.  In this case it obviously is (actually I'm a little embarrassed I
>> didn't think of this requirement).  If so, then it's simplest to test it at
>> that layer.  If the SB API is anything more than a pass-through, then you
>> might also want to write a unit test for the underlying C++ API's.  But in
>> this case the SB function will just call the underlying CommandInterpreter
>> one, so testing at the SB layer is sufficient.
>>
>> Jim
>>
>> > On Sep 19, 2017, at 10:45 AM, Zachary Turner via Phabricator <
>> reviews at reviews.llvm.org> wrote:
>> >
>> > zturner added a comment.
>> >
>> > In https://reviews.llvm.org/D37923#875322, @clayborg wrote:
>> >
>> >> We should have a test. The test would need to use pexpect or something
>> similar. If anyone has any pointer on how to make a test for this, please
>> chime in. I was thinking just a pexpect based test.
>> >
>> >
>> > This kind of thing is perfect for a unit test, but I'm not sure how
>> easy that would be with the current design.  You'd basically do something
>> like:
>> >
>> >  struct MockStream {
>> >    explicit MockStream(CommandInterpreter &Interpreter, int
>> InterruptAfter)
>> >      : CommandInterpreter(Interpreter), InterruptAfter(InterruptAfter)
>> {}
>> >
>> >    CommandInterpreter &Interpreter;
>> >    const int InterruptAfter;
>> >    int Lines = 0;
>> >    std::string Buffer;
>> >
>> >    void Write(StringRef S) {
>> >      ++Lines;
>> >      if (Lines >= InterruptAfter) {
>> >        Interpreter.Interrupt();
>> >        return;
>> >      }
>> >      Buffer += S;
>> >    }
>> >  };
>> >
>> >  TEST_F(CommandInterruption) {
>> >    CommandInterpreter Interpreter;
>> >    MockStream Stream(Interpreter, 3);
>> >    Interpreter.PrintCommandOutput(Stream, "a\nb\nc\nd\ne\nf\n");
>> >    EXPECT_EQ(Stream.Lines == 3);
>> >    EXPECT_EQ(Stream.Buffer == "a\nb\nc\n");
>> >  }
>> >
>> >
>> > https://reviews.llvm.org/D37923
>> >
>> >
>> >
>>
>>
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