tests/setup.sh: allow testsuite to fail properly with POSIX standard shells

The "((expr))" construct is not implemented by e.g. dash, so this commit
replaces the construct with a more portable one.

Signed-off-by: Lars Hjemli <hjemli@gmail.com>

1 files changed, 1 insertions, 1 deletions

@@ -113,7 +113,7 @@ run_test()
         then
                 printf " %2d) %-60s [ok]\n" $test_count "$desc"
         else
-                ((test_failed++))
+                test_failed=$(expr $test_failed + 1)
                 printf " %2d) %-60s [failed]\n" $test_count "$desc"
         fi
 }