diff --git a/unittest/force-styles/test_angle_style.cpp b/unittest/force-styles/test_angle_style.cpp
index 833aa69174..bf5cb34e7f 100644
--- a/unittest/force-styles/test_angle_style.cpp
+++ b/unittest/force-styles/test_angle_style.cpp
@@ -240,8 +240,7 @@ void generate_yaml_file(const char *outfile, const TestConfig &config)
 
     // date_generated
     std::time_t now = time(NULL);
-    block           = ctime(&now);
-    block           = block.substr(0, block.find("\n") - 1);
+    block           = utils::trim(ctime(&now));
     writer.emit("date_generated", block);
 
     // epsilon
diff --git a/unittest/force-styles/test_bond_style.cpp b/unittest/force-styles/test_bond_style.cpp
index 0d20a0bb62..d6a6e9c82d 100644
--- a/unittest/force-styles/test_bond_style.cpp
+++ b/unittest/force-styles/test_bond_style.cpp
@@ -240,8 +240,7 @@ void generate_yaml_file(const char *outfile, const TestConfig &config)
 
     // date_generated
     std::time_t now = time(NULL);
-    block           = ctime(&now);
-    block           = block.substr(0, block.find("\n") - 1);
+    block           = utils::trim(ctime(&now));
     writer.emit("date_generated", block);
 
     // epsilon
diff --git a/unittest/force-styles/test_dihedral_style.cpp b/unittest/force-styles/test_dihedral_style.cpp
index e60968bb0a..a27c50afb7 100644
--- a/unittest/force-styles/test_dihedral_style.cpp
+++ b/unittest/force-styles/test_dihedral_style.cpp
@@ -249,8 +249,7 @@ void generate_yaml_file(const char *outfile, const TestConfig &config)
 
     // date_generated
     std::time_t now = time(NULL);
-    block           = ctime(&now);
-    block           = block.substr(0, block.find("\n") - 1);
+    block           = utils::trim(ctime(&now));
     writer.emit("date_generated", block);
 
     // epsilon
diff --git a/unittest/force-styles/test_fix_timestep.cpp b/unittest/force-styles/test_fix_timestep.cpp
index e4b0fa6e02..2680367c88 100644
--- a/unittest/force-styles/test_fix_timestep.cpp
+++ b/unittest/force-styles/test_fix_timestep.cpp
@@ -198,8 +198,7 @@ void generate_yaml_file(const char *outfile, const TestConfig &config)
 
     // date_generated
     std::time_t now = time(NULL);
-    block           = ctime(&now);
-    block           = block.substr(0, block.find("\n") - 1);
+    block           = utils::trim(ctime(&now));
     writer.emit("date_generated", block);
 
     // epsilon
diff --git a/unittest/force-styles/test_improper_style.cpp b/unittest/force-styles/test_improper_style.cpp
index 858db0fb65..b13b571546 100644
--- a/unittest/force-styles/test_improper_style.cpp
+++ b/unittest/force-styles/test_improper_style.cpp
@@ -240,8 +240,7 @@ void generate_yaml_file(const char *outfile, const TestConfig &config)
 
     // date_generated
     std::time_t now = time(NULL);
-    block           = ctime(&now);
-    block           = block.substr(0, block.find("\n") - 1);
+    block           = utils::trim(ctime(&now));
     writer.emit("date_generated", block);
 
     // epsilon
diff --git a/unittest/force-styles/test_pair_style.cpp b/unittest/force-styles/test_pair_style.cpp
index aa0edfa2ad..4e1ad8d0e3 100644
--- a/unittest/force-styles/test_pair_style.cpp
+++ b/unittest/force-styles/test_pair_style.cpp
@@ -244,8 +244,7 @@ void generate_yaml_file(const char *outfile, const TestConfig &config)
 
     // date_generated
     std::time_t now = time(NULL);
-    block           = ctime(&now);
-    block           = block.substr(0, block.find("\n") - 1);
+    block           = utils::trim(ctime(&now));
     writer.emit("date_generated", block);
 
     // epsilon