diff --git a/alib2integrationtest/test-src/tests/arbologyTest.cpp b/alib2integrationtest/test-src/tests/arbologyTest.cpp
index 43b200e68f0a4ce2cc94bf4b75d3c2a74c2c7de7..36f66b70c4a03fc88e7cac64b14557df6e619a3c 100644
--- a/alib2integrationtest/test-src/tests/arbologyTest.cpp
+++ b/alib2integrationtest/test-src/tests/arbologyTest.cpp
@@ -137,7 +137,7 @@ TEST_CASE ( "Arbology tests | nonlinear pattern", "[integration]" ) {
 
 
 	SECTION ( "Test files" ) {
-		for ( const std::pair < std::string, std::string > files : pair_pattern_subject ( TestFiles::Get ( "/tree/aarbology.test[0-9]+.nonlinear.pattern.xml$" ), ".nonlinear.pattern.xml", ".subject.xml" ) ) {
+		for ( const std::pair < std::string, std::string > & files : pair_pattern_subject ( TestFiles::Get ( "/tree/aarbology.test[0-9]+.nonlinear.pattern.xml$" ), ".nonlinear.pattern.xml", ".subject.xml" ) ) {
 			CAPTURE ( std::get < 0 > ( definition ), std::get < 1 > ( definition ), files.first, files.second );
 			runTest ( exact, std::get < 1 > ( definition ), files.first, files.second );
 		}
@@ -163,7 +163,7 @@ TEST_CASE ( "Arbology tests | nonlinear pattern ends", "[integration]" ) {
 	auto pattern = EGenerateType::NONLINEAR_PATTERN_SINGLE_VAR;
 
 	SECTION ( "Test files" ) {
-		for ( const std::pair < std::string, std::string > files : pair_pattern_subject ( TestFiles::Get ( "/tree/aarbology.test[0-9]+.nonlinear.pattern.xml$" ), ".nonlinear.pattern.xml", ".subject.xml" ) ) {
+		for ( const std::pair < std::string, std::string > & files : pair_pattern_subject ( TestFiles::Get ( "/tree/aarbology.test[0-9]+.nonlinear.pattern.xml$" ), ".nonlinear.pattern.xml", ".subject.xml" ) ) {
 			CAPTURE ( std::get < 0 > ( definition ), std::get < 1 > ( definition ), files.first, files.second );
 			runTest ( exact, std::get < 1 > ( definition ), files.first, files.second );
 		}
@@ -216,7 +216,7 @@ TEST_CASE ( "Arbology tests | pattern", "[integration]" ) {
 	auto pattern = EGenerateType::PATTERN;
 
 	SECTION ( "Test files" ) {
-		for ( const std::pair < std::string, std::string > files : pair_pattern_subject ( TestFiles::Get ( "/tree/aarbology.test[0-9]+.pattern.xml$" ), ".pattern.xml", ".subject.xml" ) ) {
+		for ( const std::pair < std::string, std::string > & files : pair_pattern_subject ( TestFiles::Get ( "/tree/aarbology.test[0-9]+.pattern.xml$" ), ".pattern.xml", ".subject.xml" ) ) {
 			CAPTURE ( std::get < 0 > ( definition ), std::get < 1 > ( definition ), files.first, files.second );
 			runTest ( exact, std::get < 1 > ( definition ), files.first, files.second );
 		}
@@ -241,7 +241,7 @@ TEST_CASE ( "Arbology tests | unordered pattern", "[integration]" ) {
 	auto pattern = EGenerateType::UNORDERED_PATTERN;
 
 /*	SECTION ( "Test files" ) {
-		for ( const std::pair < std::string, std::string > files : pair_pattern_subject ( TestFiles::Get ( "/tree/aarbology.test[0-9]+.pattern.xml$" ), ".pattern.xml", ".subject.xml" ) ) {
+		for ( const std::pair < std::string, std::string > & files : pair_pattern_subject ( TestFiles::Get ( "/tree/aarbology.test[0-9]+.pattern.xml$" ), ".pattern.xml", ".subject.xml" ) ) {
 			CAPTURE ( std::get < 0 > ( definition ), std::get < 1 > ( definition ), files.first, files.second );
 			runTest ( exact, std::get < 1 > ( definition ), files.first, files.second );
 		}
@@ -273,7 +273,7 @@ TEST_CASE ( "Arbology tests | pattern ends ", "[integration]" ) {
 	auto pattern = EGenerateType::PATTERN;
 
 	SECTION ( "Test files" ) {
-		for ( const std::pair < std::string, std::string > files : pair_pattern_subject ( TestFiles::Get ( "/tree/aarbology.test[0-9]+.pattern.xml$" ), ".pattern.xml", ".subject.xml" ) ) {
+		for ( const std::pair < std::string, std::string > & files : pair_pattern_subject ( TestFiles::Get ( "/tree/aarbology.test[0-9]+.pattern.xml$" ), ".pattern.xml", ".subject.xml" ) ) {
 			CAPTURE ( std::get < 0 > ( definition ), std::get < 1 > ( definition ), files.first, files.second );
 			runTest ( exact, std::get < 1 > ( definition ), files.first, files.second );
 		}
@@ -303,7 +303,7 @@ TEST_CASE ( "Arbology tests | subtree", "[integration]" ) {
 	auto pattern = EGenerateType::SUBTREE;
 
 	SECTION ( "Test files" ) {
-		for ( const std::pair < std::string, std::string > files : pair_pattern_subject ( TestFiles::Get ( "/tree/aarbology.test[0-9]+.subtree.xml$" ), ".subtree.xml", ".subject.xml" ) ) {
+		for ( const std::pair < std::string, std::string > & files : pair_pattern_subject ( TestFiles::Get ( "/tree/aarbology.test[0-9]+.subtree.xml$" ), ".subtree.xml", ".subject.xml" ) ) {
 			CAPTURE ( std::get < 0 > ( definition ), std::get < 1 > ( definition ), files.first, files.second );
 			runTest ( exact, std::get < 1 > ( definition ), files.first, files.second );
 		}