Re: [PATCH 3/3] test-lib: '--run' to run only specific tests

> Ilya Bobyr <ilya.bobyr@gmail.com> writes:
>
>> @@ -187,10 +192,70 @@ and either can match the "t[0-9]{4}" part to skip the whole
>>  test, or t[0-9]{4} followed by ".$number" to say which
>>  particular test to skip.
>>  
>> -Note that some tests in the existing test suite rely on previous
>> -test item, so you cannot arbitrarily disable one and expect the
>> -remainder of test to check what the test originally was intended
>> -to check.
>> +For an individual test suite --run could be used to specify that
>> +only some tests should be run or that some tests should be
>> +excluded from a run.
>> +
>> +The argument for --run is a list of individual test numbers or
>> +ranges with an optional negation prefix that define what tests in
>> +a test suite to include in the run.  A range is two numbers
>> +separated with a dash and matches a range of tests with both ends
>> +been included.  You may omit the first or the second number to
>> +mean "from the first test" or "up to the very last test"
>> +respectively.
>> +
>> +Optional prefix of '!' means that the test or a range of tests
>> +should be excluded from the run.
>> +
>> +If --run starts with an unprefixed number or range the initial
>> +set of tests to run is empty. If the first item starts with '!'
>> +all the tests are added to the initial set.  After initial set is
>> +determined every test number or range is added or excluded from
>> +the set one by one, from left to right.
>> +
>> +Individual numbers or ranges could be separated either by a space
>> +or a comma.
>> +
>> +For example, common case is to run several setup tests (1, 2, 3)
>> +and then a specific test (21) that relies on that setup:
>> +
>> +    $ sh ./t9200-git-cvsexport-commit.sh --run='1 2 3 21'
>> +
>> +or:
>> +
>> +    $ sh ./t9200-git-cvsexport-commit.sh --run=1,2,3,21
>> +
>> +or:
>> +
>> +    $ sh ./t9200-git-cvsexport-commit.sh --run='-3 21'
> Good and easily understandable examples. 
>
>> +To run only tests up to a specific test (21), one could do this:
>> +
>> +    $ sh ./t9200-git-cvsexport-commit.sh --run='1-21'
>> +
>> +or this:
>> +
>> +    $ sh ./t9200-git-cvsexport-commit.sh --run='-21'
> These may be redundant, given that the reader would have to have
> grokked the earlier "-3 21" already at this point.

>> +As noted above, the test set is built going though items left to
>> +right, so this:
>> +
>> +    $ sh ./t9200-git-cvsexport-commit.sh --run='1-4 !3'
>> +
>> +will run tests 1, 2, and 4.
> I do not quite understand what you mean by "left to right"; is that
> implementation detail necessary for the user of the feature, or is
> it talking about some limitation coming from the implementation?
> e.g. perhaps "!3 1-4" would not work as people would expect "do not
> run 3, but run tests from 1 thru 4 otherwise", and warning against
> having such an expectation that cannot be fulfilled?

>> +You may use negation with ranges.  The following will run all
>> +test as a test suite except from 7 upto 11:
>> +
>> +    $ sh ./t9200-git-cvsexport-commit.sh --run='!7-11'
> Hmm, that is somewhat counter-intuitive or at least ambiguous.  I
> first thought you would be running everything but skipping 7 thru
> 11, but your explanation is that it is equivalent to "-6,8-11" (that
> is, to intersect set "-11" and set "!7").

>> +Some tests in a test suite rely on the previous tests performing
>> +certain actions, specifically some tests are designated as
>> +"setup" test, so you cannot _arbitrarily_ disable one test and
>> +expect the rest to function correctly.
> What this text (moved from the top of this hunk) tells the reader
> applies to both the traditional t0123.4 and the new "--run=1-3,5-"
> syntaxes, but the new placement of it make it sound as if it is only
> for skipping with "--run", especially because the text before this
> paragraph and also after this paragraph both apply only to "--run".

>> +--run is mostly useful when you want to focus on a specific test
>> +and know what you are doing.  Or when you want to run up to a
>> +certain test.
> Likewise for "and know what you are doing" part.  I'd suggest
> dropping that phrase from here, and/or make it part of the "you
> cannot randomly omit and expect later ones to work" that covers both
> ways to skip tests.