diff --git a/test/cppcheck_suppressions.txt b/test/cppcheck_suppressions.txt
index 2d5a2150..ebbc665e 100644
--- a/test/cppcheck_suppressions.txt
+++ b/test/cppcheck_suppressions.txt
@@ -96,7 +96,6 @@ cstyleCast
 functionStatic
 shadowFunction
 
-constVariable
 stlcstrConstructor
 stlcstrStream
 uselessCallsSubstr
diff --git a/test/optimization/optimization.cc b/test/optimization/optimization.cc
index 5443065b..f4014058 100644
--- a/test/optimization/optimization.cc
+++ b/test/optimization/optimization.cc
@@ -1,6 +1,6 @@
 /*
  * ModSecurity, http://www.modsecurity.org/
- * Copyright (c) 2015 - 2021 Trustwave Holdings, Inc. (http://www.trustwave.com/)
+ * Copyright (c) 2015 - 2023 Trustwave Holdings, Inc. (http://www.trustwave.com/)
  *
  * You may not use this file except in compliance with
  * the License.  You may obtain a copy of the License at
@@ -114,8 +114,8 @@ int main(int argc, char **argv) {
         }
 
         std::cout << " Operators" << std::endl;
-        for (auto &z : operators) {
-            auto &s = z.second;
+        for (const auto &z : operators) {
+            const auto &s = z.second;
             std::cout << "   " << std::left << std::setw(20) << z.first;
             std::cout << std::right << std::setw(4) << s;
             std::cout << std::endl;
diff --git a/test/regression/regression.cc b/test/regression/regression.cc
index b4c9dca3..6343c9e1 100644
--- a/test/regression/regression.cc
+++ b/test/regression/regression.cc
@@ -1,6 +1,6 @@
 /*
  * ModSecurity, http://www.modsecurity.org/
- * Copyright (c) 2015 - 2021 Trustwave Holdings, Inc. (http://www.trustwave.com/)
+ * Copyright (c) 2015 - 2023 Trustwave Holdings, Inc. (http://www.trustwave.com/)
  *
  * You may not use this file except in compliance with
  * the License.  You may obtain a copy of the License at
@@ -540,7 +540,7 @@ int main(int argc, char **argv) {
     }
 
     ModSecurityTestResults<RegressionTestResult> res;
-    for (std::string &a : keyList) {
+    for (const std::string &a : keyList) {
         test_number++;
         if ((test.m_test_number == 0)
             || (test_number == test.m_test_number)) {
diff --git a/test/unit/unit.cc b/test/unit/unit.cc
index 49aeabd2..4d75ba94 100644
--- a/test/unit/unit.cc
+++ b/test/unit/unit.cc
@@ -1,6 +1,6 @@
 /*
  * ModSecurity, http://www.modsecurity.org/
- * Copyright (c) 2015 - 2021 Trustwave Holdings, Inc. (http://www.trustwave.com/)
+ * Copyright (c) 2015 - 2023 Trustwave Holdings, Inc. (http://www.trustwave.com/)
  *
  * You may not use this file except in compliance with
  * the License.  You may obtain a copy of the License at
@@ -168,7 +168,7 @@ int main(int argc, char **argv) {
                 if (r.size() == 0) {
                     std::cout << KGRN << "0 tests failed.";
                 } else {
-                    for (auto &i : r) {
+                    for (const auto &i : r) {
                         if (i->skipped == true) {
                             skp++;
                         }
@@ -203,7 +203,7 @@ int main(int argc, char **argv) {
             std::cout << KGRN << "All tests passed" << RESET << std::endl;
         } else {
             int skp = 0;
-            for (auto &i : results) {
+            for (const auto &i : results) {
                 if (i->skipped == true) {
                     skp++;
                 }