Add actual test

tests/data/minimalistic.dec

@@ -1,7 +1,7 @@
 # Example decfile for testing purposes:
 
 # Line with "End" is strictly speaking not necessary
-# Such "empty" files are relevant in LHCb for example when special decays are all defined in PYthon code
+# Such "empty" files are relevant in LHCb for example when special decays are all defined in Python code
 # inserted in commented-out lines
 End
 #

tests/dec/test_dec.py

@@ -101,6 +101,14 @@ def test_non_parsed_decfile():
         p.list_decay_mother_names()
 
 
+def test_decfile_defining_stable_particle():
+    p = DecFileParser(DIR / "../data/test_stable-particle.dec")
+    p.parse()
+
+    assert p.number_of_decays == 1  # The decay of K_S0, even if no decay modes are defined
+    assert p.list_decay_modes("K_S0") == []
+
+
 def test_non_existent_decay():
     p = DecFileParser(DIR / "../data/test_example_Dst.dec")
     p.parse()