Re: [PATCH v7 1/6] t5323: test cases for git-pack-redundant

[Jiang Xin <worldhello.net@gmail.com>]

Junio C Hamano <gitster@pobox.com> 于2019年2月1日周五 上午5:44写道：
> > +create_commits () {
> > +     parent=
> > +     for name in A B C D E F G H I J K L M N O P Q R
> > +     do
> > +             test_tick &&
> > +             T=$(git write-tree) &&
>
> Move this outside loop, not for efficiency but for clarity. This
> helper function creates a single empty tree and bunch of commits
> that hold the same empty tree, arranged as a single strand of
> pearls.

Will rewrite as:

    create_commits () {
            parent=
            T=$(git write-tree) &&
            for name in A B C D E F G H I J K L M N O P Q R

>
> By the way, I had to draw a table like this to figure out ...
>
>      T A B C D E F G H I J K L M N O P Q R
> 1    x x x x x x x                       x
> 2        x x x x   x x x
> 3                x     x x x x x
> 4                        x x x x     x
> 5                  x x           x x
> 6                                x x   x
> 7                                    x x
> 8      x
>
> ... what is going on.  Perhaps something like this would help other
> readers near the top of the file (or in test_description)?

Nice chart, will edit test_description as follows:

    test_description='git pack-redundant test

    In order to test git-pack-redundant, we will create a number of
redundant
    packs in the repository `master.git`. The relationship between
packs (P1-P8)
    and objects (T,A-R) is show in the following chart:

           | T A B C D E F G H I J K L M N O P Q R
        ---+--------------------------------------
        P1 | x x x x x x x                       x
        P2 |     x x x x   x x x
        P3 |             x     x x x x x
        P4 |                     x x x x     x
        P5 |               x x           x x
        P6 |                             x x   x
        P7 |                                 x x
        P8 |   x

    Another repoisitory `shared.git` has unique objects (X-Z), while
share others
    objects through alt-odb (of `master.git`).  The relationship
between packs
    and objects is as follows:

           | T A B C D E F G H I J K L M N O P Q R   X Y Z
        ---+----------------------------------------------
        Px1|   x x x                                 x x x
        Px2|         x x x                           x x x
    '

>
>
> > +format_packfiles () {
> > +     sed \
> > +             -e "s#.*/pack-\(.*\)\.idx#\1#" \
> > +             -e "s#.*/pack-\(.*\)\.pack#\1#" |
> > +     sort -u |
> > +     while read p
> > +     do
> > +             if test -z "$(eval echo \${P$p})"
> > +             then
> > +                     echo $p
>
> All the "expected output" below will expect P$n:${P$n} prepared by
> various create_pack_$n helpers we saw earlier, so an unknown
> packfile would be detected as a line that this emits.  Is that the
> idea?

Right.  During the reroll, a typo makes an empty output, so I decide
to make this change.


> > +             else
> > +                     eval echo "\${P$p}"
> > +             fi
> > +     done |
> > +     sort
> > +}
> > +
> > +test_expect_success 'setup master.git' '
> > +     git init --bare master.git &&
> > +     cd master.git &&
> > +     create_commits
> > +'
>
> Everything below will be done inside master.git?  Avoid cd'ing
> around in random places in the test script, as a failure in any of
> the steps that does cd would start later tests in an unexpected
> place, if you can.

The first 10 test cases will run inside master.git, and others will
run inside shared.git.  Only run cd inside the two `setup` test cases.

> > +cat >expected <<EOF
> > +P2:$P2
> > +EOF
> > +
> > +test_expect_success 'one of pack-2/pack-3 is redundant' '
> > +     git pack-redundant --all >out &&
> > +     format_packfiles <out >actual &&
> > +     test_cmp expected actual
> > +'
>
> Do the preparation of file "expect" (most of the tests compare
> 'expect' vs 'actual', not 'expected') _inside_ the next test that
> uses it.  i.e.
>
>         test_expect_success 'with 1 4 and 5, either 2 or 3 can be omitted' '
>                 cat >expect <<-EOF &&
>                 P2:$P2
>                 EOF
>                 git pack-redundant --all >out &&
>                 format ... >actual &&
>                 test_cmp expect actual
>         '

Will do.

> > +test_expect_success 'setup shared.git' '
> > +     cd "$TRASH_DIRECTORY" &&
> > +     git clone -q --mirror master.git shared.git &&
>
> Why "-q"?

To make verbose output cleaner.

> > +     cd shared.git &&
> > +     printf "../../master.git/objects" >objects/info/alternates
> > +'
>
> Why not echo?  I recall designing the alternates file to be a plain
> text file.  Is it necessary to leave the line incomplete?

Forgot "\n", will append.

>
> > +test_expect_success 'remove redundant packs by alt-odb, no packs left' '
> > +     git pack-redundant --all --alt-odb | xargs rm &&
> > +     git fsck --no-progress &&
>
> Why "--no-progress"?

To make verbose output cleaner.

>
> > +     test_must_fail git pack-redundant --all --alt-odb >actual 2>&1 &&
> > +     test_cmp expected actual
> > +'
> > +
> > +create_commits_others () {
> > +     parent=$(git rev-parse HEAD)

Will append "&&".