diff --git a/unittest/c-library/test_library_mpi.cpp b/unittest/c-library/test_library_mpi.cpp
index e0e2cc3c12..5effb31b4d 100644
--- a/unittest/c-library/test_library_mpi.cpp
+++ b/unittest/c-library/test_library_mpi.cpp
@@ -86,7 +86,7 @@ public:
         finalize_test = false;
     }
 
-  
+
     virtual void OnTestPartResult(const TestPartResult& test_part_result) override {
         // Called after a failed assertion or a SUCCESS().
         // test_part_result()
@@ -105,7 +105,7 @@ public:
             results.push_back(TestPartResult(test_part_result.type(), test_part_result.file_name(), test_part_result.line_number(), proc_message.str().c_str()));
         }
     }
-  
+
     virtual void OnTestEnd(const TestInfo& test_info) override {
         // Called after a test ends.
         MPI_Barrier(comm);
@@ -195,11 +195,11 @@ public:
                 }
                 results.pop_front();
             }
-            
+
             default_listener->OnTestEnd(test_info);
         }
     }
-  
+
     virtual void OnTestSuiteEnd(const TestSuite& test_suite) override {
         if(me == 0) default_listener->OnTestSuiteEnd(test_suite);
     }
@@ -217,11 +217,11 @@ public:
     virtual void OnEnvironmentsTearDownEnd(const UnitTest& unit_test) override {
         if(me == 0) default_listener->OnEnvironmentsTearDownEnd(unit_test);
     }
-  
+
     virtual void OnTestIterationEnd(const UnitTest& unit_test, int iteration) override {
         if(me == 0) default_listener->OnTestIterationEnd(unit_test, iteration);
     }
-  
+
     virtual void OnTestProgramEnd(const UnitTest& unit_test) override {
         if(me == 0) default_listener->OnTestProgramEnd(unit_test);
     }
@@ -258,7 +258,7 @@ TEST(MPI, global_box)
 
     lammps_extract_box(lmp, boxlo, boxhi, &xy, &yz, &xz, pflags, &boxflag);
     ::testing::internal::GetCapturedStdout();
-    
+
     EXPECT_EQ(boxlo[0], 0.0);
     EXPECT_EQ(boxlo[1], 0.0);
     EXPECT_EQ(boxlo[2], 0.0);
@@ -266,7 +266,64 @@ TEST(MPI, global_box)
     EXPECT_EQ(boxhi[0], 2.0);
     EXPECT_EQ(boxhi[1], 2.0);
     EXPECT_EQ(boxhi[2], 2.0);
-    
+
+    ::testing::internal::CaptureStdout();
+    lammps_close(lmp);
+    ::testing::internal::GetCapturedStdout();
+};
+
+TEST(MPI, sub_box)
+{
+    int nprocs, me;
+    MPI_Comm_size(MPI_COMM_WORLD, &nprocs);
+    MPI_Comm_rank(MPI_COMM_WORLD, &me);
+    EXPECT_EQ(nprocs, 4);
+    EXPECT_GT(me, -1);
+    EXPECT_LT(me, 5);
+
+    double boxlo[3];
+    double boxhi[3];
+    double xy  = 0.0;
+    double yz  = 0.0;
+    double xz  = 0.0;
+    int pflags[3];
+    int boxflag;
+
+    ::testing::internal::CaptureStdout();
+    const char *args[] = {"LAMMPS_test", "-log",      "none",
+                          "-echo",       "screen",    "-nocite"};
+    char **argv = (char **)args;
+    int argc    = sizeof(args) / sizeof(char *);
+    void * lmp = lammps_open(argc, argv, MPI_COMM_WORLD, nullptr);
+    lammps_command(lmp, "units           lj");
+    lammps_command(lmp, "atom_style      atomic");
+    lammps_command(lmp, "region          box block 0 2 0 2 0 2");
+    lammps_command(lmp, "create_box      1 box");
+
+    lammps_extract_box(lmp, boxlo, boxhi, &xy, &yz, &xz, pflags, &boxflag);
+    ::testing::internal::GetCapturedStdout();
+
+    EXPECT_EQ(boxlo[0], 0.0);
+    EXPECT_EQ(boxlo[1], 0.0);
+    EXPECT_EQ(boxlo[2], 0.0);
+
+    EXPECT_EQ(boxhi[0], 2.0);
+    EXPECT_EQ(boxhi[1], 2.0);
+    EXPECT_EQ(boxhi[2], 2.0);
+
+    double * sublo = (double*)lammps_extract_global(lmp, "sublo");
+    double * subhi = (double*)lammps_extract_global(lmp, "subhi");
+
+    ASSERT_NE(sublo, nullptr);
+    ASSERT_NE(subhi, nullptr);
+
+    EXPECT_GE(sublo[0], boxlo[0]);
+    EXPECT_GE(sublo[1], boxlo[1]);
+    EXPECT_GE(sublo[2], boxlo[2]);
+    EXPECT_LE(subhi[0], boxhi[0]);
+    EXPECT_LE(subhi[1], boxhi[1]);
+    EXPECT_LE(subhi[2], boxhi[2]);
+
     ::testing::internal::CaptureStdout();
     lammps_close(lmp);
     ::testing::internal::GetCapturedStdout();