Add tests and fix event counting for Jetscape

Fix num_output_per_event() so that it starts counting from 0 for Oscar
and from 1 for Jetscape files. Also add test for warning in case of
empty event list.

src/sparkx/BaseStorer.py

@@ -560,7 +560,7 @@ def _update_num_output_per_event_after_filter(self) -> None:
             # Handle the case where num_output_per_event_ is a two-dimensional array
             updated_num_output_per_event = np.ndarray((len(self.particle_list_),2), dtype=int)
             for event in range(len(self.particle_list_)):
-                updated_num_output_per_event[event][0] = event
+                updated_num_output_per_event[event][0] = event + self.num_output_per_event_[0][0]
                 updated_num_output_per_event[event][1] = len(
                     self.particle_list_[event]
                 )

src/sparkx/Filter.py

@@ -797,15 +797,15 @@ def spacetime_rapidity_cut(particle_list, cut_value):
 
 def multiplicity_cut(particle_list, cut_value_tuple):
     """
-    Apply multiplicity cut. Remove all events with a multiplicity not coplying
+    Apply multiplicity cut. Remove all events with a multiplicity not complying
     with cut_value_tuple.
 
     Parameters
     ----------
     particle_list:
         List with lists containing particle objects for the events
 
-    multiplicity_range : tuple
+    cut_value_tuple : tuple
         Upper and lower bound for multiplicity. If the multiplicity of an event is
         not in this range, the event is discarded. The range is inclusive on the 
         lower bound and exclusive on the upper bound.

src/sparkx/Jetscape.py

@@ -130,7 +130,7 @@ class Jetscape(BaseStorer):
 
         >>> jetscape = Jetscape(JETSCAPE_FILE_PATH)
         >>>
-        >>> pions = jetscape.multiplicity_cut(500).participants().particle_species((211, -211, 111))
+        >>> pions = jetscape.multiplicity_cut(500, None).participants().particle_species((211, -211, 111))
         >>>
         >>> # save the pions of all events as nested list
         >>> pions_list = pions.particle_list()
@@ -150,7 +150,7 @@ class Jetscape(BaseStorer):
     Let's assume we only want to keep pions in events with a
     multiplicity > 500:
 
-        >>> jetscape = Jetscape(JETSCAPE_FILE_PATH, filters={'multiplicity_cut':500, 'particle_species':(211, -211, 111)}})
+        >>> jetscape = Jetscape(JETSCAPE_FILE_PATH, filters={'multiplicity_cut':(500,None), 'particle_species':(211, -211, 111)}})
         >>>
         >>> # print the pions to a jetscape file
         >>> jetscape.print_particle_lists_to_file('./particle_lists.dat')
@@ -304,6 +304,8 @@ def print_particle_lists_to_file(self, output_file: str) -> None:
             raise ValueError("The number of output per event is empty.")
         if self.num_events_ is None:
             raise ValueError("The number of events is empty.")
+        if self.num_events_ == 0:
+            raise ValueError("The number of events is zero.")
 
         # Open the output file with buffered writing (25 MB)
         with open(output_file, "w", buffering=25 * 1024 * 1024) as f_out:

src/sparkx/Oscar.py

@@ -134,7 +134,7 @@ class Oscar(BaseStorer):
 
         >>> oscar = Oscar(OSCAR_FILE_PATH)
         >>>
-        >>> pions = oscar.multiplicity_cut(500).participants().particle_species((211, -211, 111))
+        >>> pions = oscar.multiplicity_cut(500, None).participants().particle_species((211, -211, 111))
         >>>
         >>> # save the pions of all events as nested list
         >>> pions_list = pions.particle_list()
@@ -154,7 +154,7 @@ class Oscar(BaseStorer):
     Let's assume we only want to keep participant pions in events with a
     multiplicity > 500:
 
-        >>> oscar = Oscar(OSCAR_FILE_PATH, filters={'multiplicity_cut':500, 'participants':True, 'particle_species':(211, -211, 111)})
+        >>> oscar = Oscar(OSCAR_FILE_PATH, filters={'multiplicity_cut':(500,None), 'participants':True, 'particle_species':(211, -211, 111)})
         >>>
         >>> # print the pions to an oscar file
         >>> oscar.print_particle_lists_to_file('./particle_lists.oscar')

tests/test_Oscar.py

@@ -684,6 +684,16 @@ def test_standard_oscar_print(tmp_path, output_path):
     os.remove(output_path)
 
 
+def test_empty_oscar_print(tmp_path, output_path):
+    tmp_oscar_file = create_temporary_oscar_file(
+        tmp_path, 5, "Oscar2013", [1, 7, 0, 36, 5]
+    )
+    oscar = Oscar(tmp_oscar_file).multiplicity_cut((100000000,None))
+    with pytest.warns(UserWarning):
+        oscar.print_particle_lists_to_file(output_path)
+    os.remove(output_path)
+
+
 def test_extended_oscar_print(tmp_path, output_path):
     tmp_oscar_file = create_temporary_oscar_file(
         tmp_path, 5, "Oscar2013Extended", [4, 1, 42, 0, 3]