diff --git a/src/MANYBODY/pair_comb.h b/src/MANYBODY/pair_comb.h
index ffde09219d..ec4e362f0b 100644
--- a/src/MANYBODY/pair_comb.h
+++ b/src/MANYBODY/pair_comb.h
@@ -38,7 +38,6 @@ class PairComb : public Pair {
   virtual double yasu_char(double *, int &);
   double enegtot;
 
- protected:
   struct Param {
     double lam11,lam12,lam21,lam22;
     double c,d,h;
@@ -60,6 +59,7 @@ class PairComb : public Pair {
     static const int NPARAMS_PER_LINE = 49;
   };
 
+ protected:
   double cutmax;                // max cutoff for all elements
   int nelements;                // # of unique elements
   char **elements;              // names of unique elements
diff --git a/src/MANYBODY/pair_comb3.h b/src/MANYBODY/pair_comb3.h
index 210f843139..bade95e88c 100644
--- a/src/MANYBODY/pair_comb3.h
+++ b/src/MANYBODY/pair_comb3.h
@@ -38,7 +38,6 @@ class PairComb3 : public Pair {
   double enegtot;
 
  // general potential parameters
- protected:
   struct Param {
     int ielement,jelement,kelement,powermint;
     int ielementgp,jelementgp,kelementgp;       //element group
@@ -56,8 +55,11 @@ class PairComb3 : public Pair {
     double veps, vsig, pcna, pcnb, pcnc, pcnd, polz, curl, pcross;
     double paaa, pbbb;
     double curlcut1, curlcut2, curl0;
+    static const int NPARAMS_PER_LINE = 74;
   };
 
+ protected:
+
   // general setups
   int nelements;                        // # of unique elements
   int ***elem2param;                    // mapping from element triplets to parameters
diff --git a/unittest/CMakeLists.txt b/unittest/CMakeLists.txt
index 2d1663272f..531e943f6c 100644
--- a/unittest/CMakeLists.txt
+++ b/unittest/CMakeLists.txt
@@ -3,3 +3,5 @@ include(GTest)
 add_subdirectory(force-styles)
 
 add_subdirectory(utils)
+
+add_subdirectory(formats)
diff --git a/unittest/formats/CMakeLists.txt b/unittest/formats/CMakeLists.txt
new file mode 100644
index 0000000000..47d24724e5
--- /dev/null
+++ b/unittest/formats/CMakeLists.txt
@@ -0,0 +1,4 @@
+add_executable(test_potential_file_reader test_potential_file_reader.cpp)
+target_link_libraries(test_potential_file_reader PRIVATE lammps GTest::GMock GTest::GTest)
+add_test(NAME PotentialFileReader COMMAND test_potential_file_reader WORKING_DIRECTORY ${CMAKE_CURRENT_BINARY_DIR})
+set_tests_properties(PotentialFileReader PROPERTIES ENVIRONMENT "LAMMPS_POTENTIALS=${LAMMPS_POTENTIALS_DIR}")
diff --git a/unittest/formats/test_potential_file_reader.cpp b/unittest/formats/test_potential_file_reader.cpp
new file mode 100644
index 0000000000..51477f7ada
--- /dev/null
+++ b/unittest/formats/test_potential_file_reader.cpp
@@ -0,0 +1,57 @@
+#include "gmock/gmock.h"
+#include "gtest/gtest.h"
+#include "potential_file_reader.h"
+#include "lammps.h"
+#include "utils.h"
+#include "MANYBODY/pair_sw.h"
+#include "MANYBODY/pair_comb.h"
+#include "MANYBODY/pair_comb3.h"
+
+#include <mpi.h>
+
+using namespace LAMMPS_NS;
+
+const int LAMMPS_NS::PairSW::Param::NPARAMS_PER_LINE;
+const int LAMMPS_NS::PairComb::Param::NPARAMS_PER_LINE;
+const int LAMMPS_NS::PairComb3::Param::NPARAMS_PER_LINE;
+
+class PotenialFileReaderTest : public ::testing::Test {
+protected:
+    LAMMPS * lmp;
+
+    void SetUp() override {
+        const char *args[] = {"PotentialFileReaderTest", "-log", "none", "-echo", "screen", "-nocite" };
+        char **argv = (char **)args;
+        int argc = sizeof(args)/sizeof(char *);
+        lmp = new LAMMPS(argc, argv, MPI_COMM_WORLD);
+    }
+
+    void TearDown() override {
+        delete lmp;
+    }
+};
+
+TEST_F(PotenialFileReaderTest, Si) {
+    PotentialFileReader reader(lmp, "Si.sw", "Stillinger-Weber");
+    auto line = reader.next_line(PairSW::Param::NPARAMS_PER_LINE);
+    ASSERT_EQ(utils::count_words(line), PairSW::Param::NPARAMS_PER_LINE);
+}
+
+TEST_F(PotenialFileReaderTest, Comb) {
+    PotentialFileReader reader(lmp, "ffield.comb", "COMB");
+    auto line = reader.next_line(PairComb::Param::NPARAMS_PER_LINE);
+    ASSERT_EQ(utils::count_words(line), PairComb::Param::NPARAMS_PER_LINE);
+}
+
+TEST_F(PotenialFileReaderTest, Comb3) {
+    PotentialFileReader reader(lmp, "ffield.comb3", "COMB3");
+    auto line = reader.next_line(PairComb3::Param::NPARAMS_PER_LINE);
+    ASSERT_EQ(utils::count_words(line), PairComb3::Param::NPARAMS_PER_LINE);
+}
+
+int main(int argc, char **argv)
+{
+    MPI_Init(&argc, &argv);
+    ::testing::InitGoogleMock(&argc, argv);
+    return RUN_ALL_TESTS();
+}