Thanks for the review, Igor!
Here is the new commit message with your suggestions in mind:
==========================================================
    test: port lua-Harness to Test.Assertion
    Backports conversion to Test.Assertion patch[1] from lua-Harness suite.
    As a result of this change out-of-source testing is broken, but the
    previous assertion using package.path as a second argument worked fine.
    Because of that, this commit includes fix, that was made by this patch[2]
    in mainline lua-Harness.
    [1]:  https://framagit.org/fperrad/lua-Harness/-/commit/074fefa
    [2]:  https://framagit.org/fperrad/lua-Harness/-/commit/c4451fe
    Part of tarantool/tarantool#5970
    Part of tarantool/tarantool#4473
 
==========================================================
 
 
 
>Igor Munkin wrote:
> 
>Max,
>
>Thanks for the patch! LGTM, except the several nits.
>
>On 20.07.21, Maxim Kokryashkin wrote:
>> Backports conversion to Test.Assertion patch[1] from lua-Harness suite
>
>Typo: Dot is missing at the end of the sentence.
>
>>
>> As a result out of this change out-of-source testing is broken, but the
>
>Typo: s/As a result out of/As a result of/.
>
>> previous assertion using package.path as a second argument worked fine.
>> Because of that, this commit includes fix, that was made by this patch[2]
>> in mainline lua-Harness.
>>
>> [1]:  https://framagit.org/fperrad/lua-Harness/-/commit/074fefa51da1276078f735fa8fb568963fe541f1
>> [2]:  https://framagit.org/fperrad/lua-Harness/-/commit/c4451fe06fcdc0d83a72dfa56eaae3ed26151c04
>
>Minor: You can strip commit hash in the links above up to 7 symbols to
>shorted them a bit. Feel free to ignore.
>
>>
>> Part of tarantool/tarantool#5970
>> Part of tarantool/tarantool#4473
>> ---
>> Additional comments on issue with out-of-source testing:
>>  https://github.com/tarantool/tarantool/issues/5970#issuecomment-880158605
>>
>> test/lua-Harness-tests/090-tap.t | 8 +-
>> test/lua-Harness-tests/091-profile.t | 10 +-
>> test/lua-Harness-tests/101-boolean.t | 126 +--
>> test/lua-Harness-tests/102-function.t | 218 ++---
>> test/lua-Harness-tests/103-nil.t | 126 +--
>> test/lua-Harness-tests/104-number.t | 270 +++----
>> test/lua-Harness-tests/105-string.t | 308 ++++----
>> test/lua-Harness-tests/106-table.t | 132 ++--
>> test/lua-Harness-tests/107-thread.t | 128 +--
>> test/lua-Harness-tests/108-userdata.t | 124 +--
>> test/lua-Harness-tests/200-examples.t | 12 +-
>> test/lua-Harness-tests/201-assign.t | 82 +-
>> test/lua-Harness-tests/202-expr.t | 138 ++--
>> test/lua-Harness-tests/203-lexico.t | 66 +-
>> test/lua-Harness-tests/204-grammar.t | 76 +-
>> test/lua-Harness-tests/211-scope.t | 24 +-
>> test/lua-Harness-tests/212-function.t | 138 ++--
>> test/lua-Harness-tests/213-closure.t | 32 +-
>> test/lua-Harness-tests/214-coroutine.t | 96 +--
>> test/lua-Harness-tests/221-table.t | 54 +-
>> test/lua-Harness-tests/222-constructor.t | 34 +-
>> test/lua-Harness-tests/223-iterator.t | 18 +-
>> test/lua-Harness-tests/231-metatable.t | 232 +++---
>> test/lua-Harness-tests/232-object.t | 38 +-
>> .../241-standalone.t.disabled | 116 +--
>> test/lua-Harness-tests/242-luac.t | 80 +-
>> test/lua-Harness-tests/301-basic.t | 748 +++++++++---------
>> test/lua-Harness-tests/303-package.t | 119 +--
>> test/lua-Harness-tests/304-string.t | 648 +++++++--------
>> test/lua-Harness-tests/305-utf8.t | 4 +-
>> test/lua-Harness-tests/306-table.t | 186 ++---
>> test/lua-Harness-tests/307-math.t | 266 +++----
>> test/lua-Harness-tests/308-io.t | 248 +++---
>> test/lua-Harness-tests/309-os.t | 158 ++--
>> test/lua-Harness-tests/310-debug.t | 226 +++---
>> test/lua-Harness-tests/311-bit32.t | 70 +-
>> test/lua-Harness-tests/314-regex.t | 8 +-
>> test/lua-Harness-tests/320-stdin.t | 26 +-
>> test/lua-Harness-tests/401-bitop.t | 60 +-
>> test/lua-Harness-tests/402-ffi.t | 78 +-
>> test/lua-Harness-tests/403-jit.t | 96 +--
>> test/lua-Harness-tests/404-ext.t | 162 ++--
>> test/lua-Harness-tests/411-luajit.t.disabled | 166 ++--
>> test/lua-Harness-tests/lexico52/lexico.t | 22 +-
>> test/lua-Harness-tests/lexico53/boolean.t | 44 +-
>> test/lua-Harness-tests/lexico53/function.t | 72 +-
>> test/lua-Harness-tests/lexico53/lexico.t | 14 +-
>> test/lua-Harness-tests/lexico53/nil.t | 44 +-
>> test/lua-Harness-tests/lexico53/number.t | 224 +++---
>> test/lua-Harness-tests/lexico53/string.t | 196 ++---
>> test/lua-Harness-tests/lexico53/table.t | 44 +-
>> test/lua-Harness-tests/lexico53/thread.t | 44 +-
>> test/lua-Harness-tests/lexico53/userdata.t | 44 +-
>> test/lua-Harness-tests/lexico53/utf8.t | 240 +++---
>> test/lua-Harness-tests/lexico54/lexico.t | 8 +-
>> test/lua-Harness-tests/lexico54/metatable.t | 14 +-
>> test/lua-Harness-tests/lexico54/utf8.t | 34 +-
>> test/lua-Harness-tests/lexicojit/basic.t | 14 +-
>> test/lua-Harness-tests/lexicojit/ext.t | 26 +-
>> test/lua-Harness-tests/lexicojit/lexico.t | 30 +-
>> test/lua-Harness-tests/tap.lua | 96 ++-
>> 61 files changed, 3599 insertions(+), 3566 deletions(-)
>>
>
><snipped>
>
>> --
>> 2.32.0
>>
>
>--
>Best regards,
>IM