diff --git a/unittest/force-styles/angle_style.cpp b/unittest/force-styles/angle_style.cpp
index 3dd7246804..51b51de1f6 100644
--- a/unittest/force-styles/angle_style.cpp
+++ b/unittest/force-styles/angle_style.cpp
@@ -193,18 +193,6 @@ void data_lammps(LAMMPS_NS::LAMMPS *lmp, const TestConfig &cfg)
 }
 
 
-// read/parse yaml file
-
-bool read_yaml_file(const char *infile, TestConfig &config)
-{
-    auto reader = TestConfigReader(config);
-    if (reader.parse_file(infile))
-        return false;
-    
-    config.basename = reader.get_basename();
-    return true;
-}
-
 // re-generate yaml file with current settings.
 
 void generate_yaml_file(const char *outfile, const TestConfig &config)
diff --git a/unittest/force-styles/bond_style.cpp b/unittest/force-styles/bond_style.cpp
index 00c51a3b00..d0bf999173 100644
--- a/unittest/force-styles/bond_style.cpp
+++ b/unittest/force-styles/bond_style.cpp
@@ -194,18 +194,6 @@ void data_lammps(LAMMPS_NS::LAMMPS *lmp, const TestConfig &cfg)
     lmp->input->one("run 0 post no");
 }
 
-// read/parse yaml file
-
-bool read_yaml_file(const char *infile, TestConfig &config)
-{
-    auto reader = TestConfigReader(config);
-    if (reader.parse_file(infile))
-        return false;
-    
-    config.basename = reader.get_basename();
-    return true;
-}
-
 // re-generate yaml file with current settings.
 
 void generate_yaml_file(const char *outfile, const TestConfig &config)
diff --git a/unittest/force-styles/pair_style.cpp b/unittest/force-styles/pair_style.cpp
index 026e71fbda..3ead16f0c7 100644
--- a/unittest/force-styles/pair_style.cpp
+++ b/unittest/force-styles/pair_style.cpp
@@ -194,15 +194,6 @@ void data_lammps(LAMMPS_NS::LAMMPS *lmp, const TestConfig &cfg)
 
 // read/parse yaml file
 
-bool read_yaml_file(const char *infile, TestConfig &config)
-{
-    auto reader = TestConfigReader(config);
-    if (reader.parse_file(infile))
-        return false;
-    
-    config.basename = reader.get_basename();
-    return true;
-}
 
 // re-generate yaml file with current settings.
 
diff --git a/unittest/force-styles/test_main.cpp b/unittest/force-styles/test_main.cpp
index ce3a0a3116..49f3fc4029 100644
--- a/unittest/force-styles/test_main.cpp
+++ b/unittest/force-styles/test_main.cpp
@@ -13,14 +13,25 @@
 
 #include "test_main.h"
 #include "test_config.h"
+#include "test_config_reader.h"
 #include "gtest/gtest.h"
 
 #include <mpi.h>
 #include <cstring>
 #include <iostream>
 
+// common read_yaml_file function
+bool read_yaml_file(const char *infile, TestConfig &config)
+{
+    auto reader = TestConfigReader(config);
+    if (reader.parse_file(infile))
+        return false;
+    
+    config.basename = reader.get_basename();
+    return true;
+}
+
 // need to be defined in unit test body
-extern bool read_yaml_file(const char *, TestConfig &);
 extern void generate_yaml_file(const char *, const TestConfig &);
 
 void usage(std::ostream &out, const char *name)