allow process version to be printed to terminal (#3379)

* allow process version to be printed to terminal

* add version monkeypatch to test_run_mode

process/__init__.py

@@ -0,0 +1,3 @@
+from importlib.metadata import version
+
+__version__ = version("process")

process/main.py

@@ -74,6 +74,7 @@
 from process.impurity_radiation import initialise_imprad
 from process.caller import write_output_files
 
+import process
 
 from pathlib import Path
 import os
@@ -191,6 +192,11 @@ def parse_args(self, args):
             action="store_true",
             help="Produce a filled json from --mfile arg in working dir",
         )
+        parser.add_argument(
+            "--version",
+            action="store_true",
+            help="Print the version of PROCESS to the terminal",
+        )
 
         # If args is not None, then parse the supplied arguments. This is likely
         # to come from the test suite when testing command-line arguments; the
@@ -202,6 +208,9 @@ def parse_args(self, args):
 
     def run_mode(self):
         """Determine how to run Process."""
+        if self.args.version:
+            print(process.__version__)
+            return
         # Store run object: useful for testing
         if self.args.varyiterparams:
             self.run = VaryRun(self.args.varyiterparamsconfig, self.args.solver)

tests/unit/test_main.py

@@ -101,6 +101,7 @@ def test_run_mode(process_obj, monkeypatch):
     # Mock the args attributes for --varyiterparams and --varyiterparamsconfig
     monkeypatch.setattr(process_obj, "args", argparse.Namespace(), raising=False)
     monkeypatch.setattr(process_obj.args, "varyiterparams", True, raising=False)
+    monkeypatch.setattr(process_obj.args, "version", False, raising=False)
     monkeypatch.setattr(
         process_obj.args, "varyiterparamsconfig", "file.conf", raising=False
     )