- [ -n "$_list_size" -a -n "$_bisection_size" ] || error "test_bisection_diff failed"
- test_expect_success "bisection diff $_bisect_option $_head $* <= $_max_diff" "[ $(bc_expr "floor(abs($_list_size/2)-$_bisection_size)") -le $_max_diff ]"
+ [ -n "$_list_size" -a -n "$_bisection_size" ] ||
+ error "test_bisection_diff failed"
+
+ # Test if bisection size is close to half of list size within
+ # tolerance.
+ #
+ _bisect_err=`expr $_list_size - $_bisection_size \* 2`
+ test "$_bisect_err" -lt 0 && _bisect_err=`expr 0 - $_bisect_err`
+ _bisect_err=`expr $_bisect_err / 2` ; # floor
+
+ test_expect_success \
+ "bisection diff $_bisect_option $_head $* <= $_max_diff" \
+ 'test $_bisect_err -le $_max_diff'