diff --git a/unittest/c-library/test_library_open.cpp b/unittest/c-library/test_library_open.cpp
index c75fd3738b..1cd65d843d 100644
--- a/unittest/c-library/test_library_open.cpp
+++ b/unittest/c-library/test_library_open.cpp
@@ -198,3 +198,32 @@ TEST(lammps_open_fortran, no_args)
     if (verbose) std::cout << output;
     MPI_Comm_free(&mycomm);
 }
+
+TEST(lammps_open_no_mpi, lammps_error)
+{
+    const char *args[] = {"liblammps", "-log", "none", "-nocite"};
+    char **argv        = (char **)args;
+    int argc           = sizeof(args) / sizeof(char *);
+
+    ::testing::internal::CaptureStdout();
+    void *alt_ptr;
+    void *handle       = lammps_open_no_mpi(argc, argv, &alt_ptr);
+    std::string output = ::testing::internal::GetCapturedStdout();
+    EXPECT_EQ(handle, alt_ptr);
+    LAMMPS_NS::LAMMPS *lmp = (LAMMPS_NS::LAMMPS *)handle;
+
+    EXPECT_EQ(lmp->world, MPI_COMM_WORLD);
+    EXPECT_EQ(lmp->infile, stdin);
+    EXPECT_NE(lmp->screen, nullptr);
+    EXPECT_EQ(lmp->logfile, nullptr);
+    EXPECT_EQ(lmp->citeme, nullptr);
+    EXPECT_EQ(lmp->suffix_enable, 0);
+
+    EXPECT_STREQ(lmp->exename, "liblammps");
+    EXPECT_EQ(lmp->num_package, 0);
+    ::testing::internal::CaptureStdout();
+    lammps_error(handle, 0, "test_warning");
+    output = ::testing::internal::GetCapturedStdout();
+    EXPECT_THAT(output, HasSubstr("WARNING: test_warning"));
+}
+
diff --git a/unittest/python/python-open.py b/unittest/python/python-open.py
index 328745ded0..3c9165b8c8 100644
--- a/unittest/python/python-open.py
+++ b/unittest/python/python-open.py
@@ -45,11 +45,21 @@ class PythonOpen(unittest.TestCase):
 
     def testWithArgs(self):
         """Create LAMMPS instance with a few arguments"""
-        lmp=lammps(name=self.machine,
-                   cmdargs=['-nocite','-sf','opt','-log','none'])
+        lmp=lammps(name=self.machine,cmdargs=['-nocite','-sf','opt','-log','none'])
         self.assertIsNot(lmp.lmp,None)
         self.assertEqual(lmp.opened,1)
 
+    def testError(self):
+        """Print warning message through LAMMPS Error class"""
+        lmp=lammps(name=self.machine,cmdargs=['-nocite','-log','none','-screen','tmp.error.output'])
+        lmp.error(0,'test_warning')
+        lmp.close()
+        with open('tmp.error.output','r') as f:
+            output = f.read()
+        self.assertTrue('LAMMPS' in output)
+        self.assertTrue('Total wall time' in output)
+        self.assertTrue('WARNING: test_warning' in output)
+
     def testContextManager(self):
         """Automatically clean up LAMMPS instance"""
         with lammps(name=self.machine) as lmp: