diff --git a/tools/check_unit_test_structure.sh b/tools/check_unit_test_structure.sh
index 5341d6cf0c7..5b0eed3ff10 100755
--- a/tools/check_unit_test_structure.sh
+++ b/tools/check_unit_test_structure.sh
@@ -42,14 +42,14 @@ for test_file in ${test_files[@]}; do
     if [ ! -f "$filename" ] && [ ! -d "$package_dir" ]; then
         for ignore_regex in ${ignore_regexes[@]}; do
             if [[ "$relative_path" =~ $ignore_regex ]]; then
-                ((ignore_count++))
+                ignore_count=$((ignore_count + 1))
                 continue 2
             fi
         done
         echo "Unexpected test file: $base_test_path/$relative_path"
-        ((error_count++))
+        error_count=$((error_count + 1))
     fi
-    ((total_count++))
+    total_count=$((total_count + 1))
 done
 
 if [ "$ignore_count" -ne 0 ]; then
diff --git a/tox.ini b/tox.ini
index b7e68552414..61b234b2c0b 100644
--- a/tox.ini
+++ b/tox.ini
@@ -138,7 +138,8 @@ commands = bash -c "find {toxinidir}             \
 # E005 file does not begin with #! or have a .sh prefix
 # E006 check for lines longer than 79 columns
 # E042 local declaration hides errors
-         -print0 | xargs -0 bashate -v -iE006 -eE005,E042"
+# E043 Arithmetic compound has inconsistent return semantics
+         -print0 | xargs -0 bashate -v -iE006 -eE005,E042,E043"
 
 [testenv:genconfig]
 commands = {toxinidir}/tools/generate_config_file_samples.sh