check that file types are supported by Struct in load_budget

gwinc/__init__.py

@@ -140,10 +140,15 @@ def load_budget(name_or_path, freq=None, bname=None):
                 modname = 'gwinc.ifo.aLIGO'
                 bname = bname or 'aLIGO'
 
-        else:
+        elif ext == '':
             bname = bname or base
             modname = path
 
+        else:
+            raise RuntimeError(
+                "Unknown file type: {} (supported types: {}).".format(
+                    ext, Struct.STRUCT_EXT))
+
     else:
         if name_or_path not in IFOS:
             raise RuntimeError("Unknown IFO '{}' (available IFOs: {}).".format(

test/inherit/new_ifo.txt

+ifos can't be specified by a txt file, so load_budget should fail when trying to load this.

test/inherit/subdir/CustomBudget_mod.yaml

@@ -3,4 +3,4 @@
 Squeezer:
   AmplitudedB: 14
   FilterCavity:
-    Lrt: 40e-6
\ No newline at end of file
+    Lrt: 40e-6

test/inherit/test_inherit.py

@@ -92,3 +92,24 @@ def test_inherit_fail(pprint, tpath_join, fpath_join):
 
     with pytest.raises(RuntimeError):
         B_inherit2 = load_budget(fpath2)
+
+
+@pytest.mark.fast
+@pytest.mark.logic
+def test_load_fail_unknown_filetype(fpath_join):
+    """
+    Test that load_budget fails when given a file type not supported by Struct
+    """
+    with pytest.raises(RuntimeError):
+        budget = load_budget(fpath_join('new_ifo.txt'))
+
+
+@pytest.mark.fast
+@pytest.mark.logic
+def test_load_fail_unknown_ifo():
+    """
+    Test that load_budget fails when given an unknown ifo that doesn't exist
+    """
+    with pytest.raises(RuntimeError):
+        budget = load_budget('not_a_real_ifo')
+