t/t6300: introduce test_bad_atom
Introduce a new function "test_bad_atom", which is similar to
"test_atom()" but should be used to check whether the correct error
message is shown on stderr.
Like "test_atom", the new function takes three arguments. The three
arguments specify the ref, the format and the expected error message
respectively, with an optional fourth argument for tweaking
"test_expect_*" (which is by default "success").
Mentored-by: Christian Couder <christian.couder@gmail.com>
Mentored-by: Hariom Verma <hariom18599@gmail.com>
Signed-off-by: Kousik Sanagavarapu <five231003@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>