Update test for better code coverage and bufix with the gid (#937)

* Update test for better code coverage
  - apply suggestion from review in #927
* fix the test : gid is pc.id()+1 and not pc.id()

test/coreneuron/test_spikes.py

@@ -43,7 +43,10 @@ def test_spikes(use_mpi4py=False, use_nrnmpi_init=False, file_mode=False):
     # NEURON run
     nrn_spike_t = h.Vector()
     nrn_spike_gids = h.Vector()
-    pc.spike_record(-1, nrn_spike_t, nrn_spike_gids)
+
+    # rank 0 record spikes for all gid while others
+    # for specific gid. this is for better test coverage.
+    pc.spike_record(-1 if pc.id() == 0 else (pc.id()+1), nrn_spike_t, nrn_spike_gids)
 
     h.run()