Merge pull request #1 from ArVar/fix-exists

Fix exists

dedupe/variables/exists.py

@@ -5,11 +5,11 @@
 from categorical import CategoricalComparator
 
 from dedupe._typing import PredicateFunction
-from dedupe.variables.base import DerivedType
-from dedupe.variables.categorical_type import CategoricalType
+from dedupe.variables.base import DerivedType, FieldType
 
 
-class ExistsType(CategoricalType):
+
+class ExistsType(FieldType):
     type = "Exists"
     _predicate_functions: list[PredicateFunction] = []
 
@@ -30,6 +30,9 @@ def comparator(self, field_1: Any, field_2: Any) -> list[int]:
             return self.cat_comparator(0, 1)
         else:
             return self.cat_comparator(0, 0)
+
+    def __len__(self) -> int:
+        return len(self.higher_vars)
 
     # This flag tells fieldDistances in dedupe.core to pass
     # missing values (None) into the comparator

tests/test_exists.py

@@ -0,0 +1,13 @@
+import unittest
+
+import numpy
+
+from dedupe.variables.exists import ExistsType
+
+
+class TestExists(unittest.TestCase):
+    def test_comparator(self):
+        var = ExistsType("foo")
+        assert numpy.array_equal(var.comparator(None, None), [0, 0])
+        assert numpy.array_equal(var.comparator(1, 1), [1, 0])
+        assert numpy.array_equal(var.comparator(1, 0), [0, 1])