Add test for empty song database

testing/test_songs_db.py

@@ -30,6 +30,10 @@
 Songs database tests
 """
 
+import pytest
+from sqlalchemy.exc import InvalidRequestError
+from sqlalchemy.orm.exc import UnmappedInstanceError
+
 from openlp.plugins.songs.lib.db import Author, Book, MediaFile, Song, Topic
 
 
@@ -48,6 +52,24 @@ def test_empty_songdb(empty_songs_db):
     assert c(Topic) == 0
 
 
-def test_nonexisting_class(empty_songs_db):
+def test_unmapped_class(empty_songs_db):
     # test class not mapped to any sqlalchemy table
-    assert 0
+    class A(object):
+        pass
+    db = empty_songs_db
+    assert db.save_object(A()) == False
+    assert db.save_objects([A(), A()]) == False
+    # no key - new object instance is created from supplied class
+    assert type(db.get_object(A, key=None)) == A
+
+    with pytest.raises(InvalidRequestError):
+        db.get_object(A, key=1)
+    with pytest.raises(InvalidRequestError):
+        db.get_object_filtered(A, filter_clause=None)
+    with pytest.raises(InvalidRequestError):
+        db.get_all_objects(A)
+    with pytest.raises(InvalidRequestError):
+        db.get_object_count(A)
+
+    assert db.delete_object(A, key=None) == False
+    assert db.delete_all_objects(A) == False