Update test_lammps_dpa_pt.py

Author: iProzd

source/lmp/tests/test_lammps_dpa_pt.py

@@ -474,6 +474,11 @@ def test_pair_deepmd_type_map(lammps_type_map) -> None:
         )
     lammps_type_map.run(1)
 
+def test_pair_deepmd_type_map_with_null(lammps_type_map) -> None:
+    lammps_type_map.pair_style(f"deepmd {pb_file.resolve()}")
+    lammps_type_map.pair_coeff("* * H NULL")
+    lammps_type_map.run(0)
+
 
 def test_pair_deepmd_real(lammps_real) -> None:
     lammps_real.pair_style(f"deepmd {pb_file.resolve()}")