refactor: test test_dataframe_rolling_closed_param

Author: chelsea-lin

bigframes/core/compile/sqlglot/compiler.py

@@ -356,6 +356,9 @@ def compile_window(node: nodes.WindowOpNode, child: ir.SQLGlotIR) -> ir.SQLGlotI
                 observation_count = windows.apply_window_if_present(
                     sge.func("SUM", is_observation), window_spec
                 )
+                observation_count = sge.func(
+                    "COALESCE", observation_count, sge.convert(0)
+                )
             else:
                 # Operations like count treat even NULLs as valid observations
                 # for the sake of min_periods notnull is just used to convert

tests/unit/core/compile/sqlglot/snapshots/test_compile_window/test_compile_window_w_groupby_rolling/out.sql

@@ -22,10 +22,13 @@ WITH `bfcte_0` AS (
   SELECT
     *,
     CASE
-      WHEN SUM(CAST(NOT `bfcol_7` IS NULL AS INT64)) OVER (
-        PARTITION BY `bfcol_9`
-        ORDER BY `bfcol_9` ASC NULLS LAST, `rowindex` ASC NULLS LAST
-        ROWS BETWEEN 3 PRECEDING AND CURRENT ROW
+      WHEN COALESCE(
+        SUM(CAST(NOT `bfcol_7` IS NULL AS INT64)) OVER (
+          PARTITION BY `bfcol_9`
+          ORDER BY `bfcol_9` ASC NULLS LAST, `rowindex` ASC NULLS LAST
+          ROWS BETWEEN 3 PRECEDING AND CURRENT ROW
+        ),
+        0
       ) < 3
       THEN NULL
       ELSE COALESCE(
@@ -42,10 +45,13 @@ WITH `bfcte_0` AS (
   SELECT
     *,
     CASE
-      WHEN SUM(CAST(NOT `bfcol_8` IS NULL AS INT64)) OVER (
-        PARTITION BY `bfcol_9`
-        ORDER BY `bfcol_9` ASC NULLS LAST, `rowindex` ASC NULLS LAST
-        ROWS BETWEEN 3 PRECEDING AND CURRENT ROW
+      WHEN COALESCE(
+        SUM(CAST(NOT `bfcol_8` IS NULL AS INT64)) OVER (
+          PARTITION BY `bfcol_9`
+          ORDER BY `bfcol_9` ASC NULLS LAST, `rowindex` ASC NULLS LAST
+          ROWS BETWEEN 3 PRECEDING AND CURRENT ROW
+        ),
+        0
       ) < 3
       THEN NULL
       ELSE COALESCE(

tests/unit/core/compile/sqlglot/snapshots/test_compile_window/test_compile_window_w_range_rolling/out.sql

@@ -6,9 +6,12 @@ WITH `bfcte_0` AS (
   SELECT
     *,
     CASE
-      WHEN SUM(CAST(NOT `bfcol_1` IS NULL AS INT64)) OVER (
-        ORDER BY UNIX_MICROS(`bfcol_0`) ASC NULLS LAST
-        RANGE BETWEEN 2999999 PRECEDING AND CURRENT ROW
+      WHEN COALESCE(
+        SUM(CAST(NOT `bfcol_1` IS NULL AS INT64)) OVER (
+          ORDER BY UNIX_MICROS(`bfcol_0`) ASC NULLS LAST
+          RANGE BETWEEN 2999999 PRECEDING AND CURRENT ROW
+        ),
+        0
       ) < 1
       THEN NULL
       ELSE COALESCE(

tests/unit/core/compile/sqlglot/snapshots/test_compile_window/test_compile_window_w_skips_nulls_op/out.sql

@@ -7,7 +7,10 @@ WITH `bfcte_0` AS (
   SELECT
     *,
     CASE
-      WHEN SUM(CAST(NOT `int64_col` IS NULL AS INT64)) OVER (ORDER BY `rowindex` ASC NULLS LAST ROWS BETWEEN 2 PRECEDING AND CURRENT ROW) < 3
+      WHEN COALESCE(
+        SUM(CAST(NOT `int64_col` IS NULL AS INT64)) OVER (ORDER BY `rowindex` ASC NULLS LAST ROWS BETWEEN 2 PRECEDING AND CURRENT ROW),
+        0
+      ) < 3
       THEN NULL
       ELSE COALESCE(
         SUM(`int64_col`) OVER (ORDER BY `rowindex` ASC NULLS LAST ROWS BETWEEN 2 PRECEDING AND CURRENT ROW),