[PATCH 03/11] t6002: make test "set -e" clean

[Junio C Hamano <gitster@pobox.com>]

In order to catch mistakes like misspelling "test_expect_success",
we would like to eventually be able to run our test suite with the
"-e" option on.

We often use

      val=$(expr expression)

only for the computation, and it is good that "expr" exits non-zero
with syntactically invalid expression (it exits with 2) and other
errors (with 3), as we do want to notice such errors.

"expr" however also exits with "1" if it yields 0 or null X-<.

Make sure we do not fail unnecessarily under "set -e".

Signed-off-by: Junio C Hamano <gitster@pobox.com>
---
 t/t6002-rev-list-bisect.sh | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/t/t6002-rev-list-bisect.sh b/t/t6002-rev-list-bisect.sh
index daa009c9a1..1a6ffd8fbd 100755
--- a/t/t6002-rev-list-bisect.sh
+++ b/t/t6002-rev-list-bisect.sh
@@ -27,9 +27,9 @@ test_bisection_diff()
 	# Test if bisection size is close to half of list size within
 	# tolerance.
 	#
-	_bisect_err=$(expr $_list_size - $_bisection_size \* 2)
+	_bisect_err=$(expr $_list_size - $_bisection_size \* 2) && test $? -le 1
 	test "$_bisect_err" -lt 0 && _bisect_err=$(expr 0 - $_bisect_err)
-	_bisect_err=$(expr $_bisect_err / 2) ; # floor
+	_bisect_err=$(expr $_bisect_err / 2) && test $? -le 1; # floor
 
 	test_expect_success \
 	"bisection diff $_bisect_option $_head $* <= $_max_diff" \
-- 
2.53.0-886-g529cbd14ff