fixup! Fix NotStartsWith residual evaluation to return correct result

Author: ebyhr

pyiceberg/expressions/visitors.py

@@ -1906,6 +1906,7 @@ def visit_starts_with(self, term: BoundTerm, literal: LiteralValue) -> BooleanEx
 
     def visit_not_starts_with(self, term: BoundTerm, literal: LiteralValue) -> BooleanExpression:
         starts_with_result = self.visit_starts_with(term, literal)
+        # Should return opposite of visit_starts_with
         if isinstance(starts_with_result, AlwaysTrue):
             return AlwaysFalse()
         else:

tests/expressions/test_residual_evaluator.py

@@ -251,6 +251,19 @@ def test_not_in_timestamp() -> None:
     assert residual == AlwaysTrue()
 
 
+def test_starts_with() -> None:
+    schema = Schema(NestedField(1, "x", StringType()))
+    spec = PartitionSpec(PartitionField(1, 1001, IdentityTransform(), "x_part"))
+
+    predicate = StartsWith("x", "a")
+    res_eval = residual_evaluator_of(spec=spec, expr=predicate, case_sensitive=True, schema=schema)
+
+    assert res_eval.residual_for(Record("bb")) == AlwaysFalse()
+    assert res_eval.residual_for(Record("abc")) == AlwaysTrue()
+    assert res_eval.residual_for(Record("a")) == AlwaysTrue()
+    assert res_eval.residual_for(Record("zoo")) == AlwaysFalse()
+
+
 def test_not_starts_with() -> None:
     schema = Schema(NestedField(1, "x", StringType()))
     spec = PartitionSpec(PartitionField(1, 1001, IdentityTransform(), "x_part"))