fix comparator for empty fields

Author: MJedr

json_merger/comparator.py

@@ -113,6 +113,8 @@ def _get_compared_objects_at_field_path(self, obj1, obj2, field):
 
     def _have_field_equal(self, obj1, obj2, field):
         o1, o2 = self._get_compared_objects_at_field_path(obj1, obj2, field)
+        if o1 == NOTHING and o2 == NOTHING:
+            return True
         if o1 == NOTHING or o2 == NOTHING:
             return False
 

tests/unit/test_comparator.py

@@ -56,10 +56,10 @@ class MyComp(PrimaryKeyComparator):
 
     inst = MyComp(lst1, lst2)
 
-    assert not inst.get_matches('l1', 0)
-    assert not inst.get_matches('l1', 1)
-    assert not inst.get_matches('l2', 0)
-    assert not inst.get_matches('l2', 1)
+    assert inst.get_matches('l1', 0)
+    assert inst.get_matches('l1', 1)
+    assert inst.get_matches('l2', 0)
+    assert inst.get_matches('l2', 1)
     assert not inst.get_matches('l2', 3)
 
     assert inst.get_matches('l1', 2) == [(2, lst2[2])]
@@ -81,10 +81,10 @@ class MyComp(PrimaryKeyComparator):
 
     inst = MyComp(lst1, lst2)
 
-    assert not inst.get_matches('l1', 0)
-    assert not inst.get_matches('l1', 1)
-    assert not inst.get_matches('l2', 0)
-    assert not inst.get_matches('l2', 1)
+    assert inst.get_matches('l1', 0)
+    assert inst.get_matches('l1', 1)
+    assert inst.get_matches('l2', 0)
+    assert inst.get_matches('l2', 1)
     assert not inst.get_matches('l2', 3)
 
     assert inst.get_matches('l1', 2) == [(2, lst2[2])]