feat: Add nullifzero function support for local testing

Author: mkanetsuna

src/snowflake/snowpark/mock/_functions.py

@@ -707,6 +707,18 @@ def mock_abs(expr):
         return abs(expr)
 
 
+@patch("nullifzero")
+def mock_nullifzero(expr: ColumnEmulator) -> ColumnEmulator:
+    def convert_zero_to_null(value):
+        if value == 0 or value == 0.0:
+            return None
+        return value
+
+    result = expr.apply(convert_zero_to_null)
+    result.sf_type = ColumnType(expr.sf_type.datatype, nullable=True)
+    return result
+
+
 @patch("to_decimal")
 def mock_to_decimal(
     e: ColumnEmulator,

tests/mock/test_functions.py

@@ -161,6 +161,31 @@ def test_abs(session):
     assert origin_df.select(abs(col("m"))).collect() == [Row(1), Row(1), Row(2)]
 
 
+def test_nullifzero(session):
+    """Test nullifzero function converts 0 to NULL while preserving other values."""
+    from snowflake.snowpark.functions import nullifzero
+
+    df = session.create_dataframe(
+        [
+            [0],
+            [1],
+            [0.0],
+            [100],
+            [-5],
+        ],
+        schema=["value"],
+    )
+    result = df.select(nullifzero(col("value")).alias("result")).collect()
+
+    assert result == [
+        Row(RESULT=None),
+        Row(RESULT=1),
+        Row(RESULT=None),
+        Row(RESULT=100),
+        Row(RESULT=-5),
+    ]
+
+
 def test_asc_and_desc(session):
     origin_df: DataFrame = session.create_dataframe(
         [