diff --git a/src/lib/dhcpsrv/tests/daemon_unittest.cc b/src/lib/dhcpsrv/tests/daemon_unittest.cc
index 9e0527333f..d0945dfab0 100644
--- a/src/lib/dhcpsrv/tests/daemon_unittest.cc
+++ b/src/lib/dhcpsrv/tests/daemon_unittest.cc
@@ -57,11 +57,11 @@ namespace {
 class DaemonTest : public ::testing::Test {
 public:
     /// @brief Constructor
-    DaemonTest() : env_(0), copy_() {
+    DaemonTest() : env_(0), env_copy_() {
         // Take a copy of KEA_PIDFILE_DIR environment variable value
         env_ = getenv("KEA_PIDFILE_DIR");
         if (env_) {
-            copy_ = std::string(env_);
+            env_copy_ = std::string(env_);
         }
     }
 
@@ -74,8 +74,8 @@ public:
         isc::log::setDefaultLoggingOutput();
         // Restore KEA_PIDFILE_DIR environment variable value
         env_ = getenv("KEA_PIDFILE_DIR");
-        if (!copy_.empty() && (!env_ || !copy_.compare(env_))) {
-            setenv("KEA_PIDFILE_DIR", copy_.c_str(), 1);
+        if (!env_copy_.empty() && (!env_ || !env_copy_.compare(env_))) {
+            setenv("KEA_PIDFILE_DIR", env_copy_.c_str(), 1);
         }
     }
 
@@ -84,7 +84,7 @@ private:
     char* env_;
 
     /// @brief copy of KEA_PIDFILE_DIR environment variable value
-    std::string copy_;
+    std::string env_copy_;
 };