Changing SQL conversion to always use pretty=True (#248)

This drastically increases the readability of the generated SQL text when debugging, especially when errors are caused during runtime execution of the query without a clear cause unless you look at the generated SQL text. Since this changed a lot of tests, also moved all of the SQL generation tests to SQL files in a folder that either get read or written to depending on the same environment variable as planner tests.

pydough/sqlglot/execute_relational.py

@@ -26,7 +26,6 @@ def convert_relation_to_sql(
     relational: RelationalRoot,
     dialect: SQLGlotDialect,
     bindings: SqlGlotTransformBindings,
-    pretty_print_sql: bool = False,
 ) -> str:
     """
     Convert the given relational tree to a SQL string using the given dialect.
@@ -44,7 +43,7 @@ def convert_relation_to_sql(
     glot_expr: SQLGlotExpression = SQLGlotRelationalVisitor(
         dialect, bindings
     ).relational_to_sqlglot(relational)
-    return glot_expr.sql(dialect, pretty=pretty_print_sql)
+    return glot_expr.sql(dialect, pretty=True)
 
 
 def convert_dialect_to_sqlglot(dialect: DatabaseDialect) -> SQLGlotDialect:
@@ -88,12 +87,7 @@ def execute_df(
         The result of the query as a Pandas DataFrame
     """
     sqlglot_dialect: SQLGlotDialect = convert_dialect_to_sqlglot(ctx.dialect)
-    pretty_print_sql: bool = False
-    if display_sql:
-        pretty_print_sql = True
-    sql: str = convert_relation_to_sql(
-        relational, sqlglot_dialect, bindings, pretty_print_sql
-    )
+    sql: str = convert_relation_to_sql(relational, sqlglot_dialect, bindings)
     if display_sql:
         pyd_logger = get_logger(__name__)
         pyd_logger.info(f"SQL query:\n {sql}")

tests/conftest.py

@@ -152,12 +152,25 @@ def impl(file_name: str) -> str:
     return impl
 
 
+@pytest.fixture(scope="session")
+def get_sql_test_filename() -> Callable[[str], str]:
+    """
+    A function that takes in a file name and returns the path to that file
+    from within the directory of SQL text testing refsol files.
+    """
+
+    def impl(file_name: str) -> str:
+        return f"{os.path.dirname(__file__)}/test_sql_refsols/{file_name}.sql"
+
+    return impl
+
+
 @pytest.fixture
-def update_plan_tests() -> bool:
+def update_tests() -> bool:
     """
-    If True, planner tests should update the refsol file instead of verifying
-    that the test matches the file. If False, the refsol file is used to check
-    the answer.
+    If True, planner/sql tests should update the refsol file instead of
+    verifying that the test matches the file. If False, the refsol file is used
+    to check the answer.
 
     This is controlled by an environment variable `PYDOUGH_UPDATE_TESTS`.
     """

tests/test_pipeline.py

@@ -655,7 +655,7 @@ def test_pipeline_until_relational(
     get_sample_graph: graph_fetcher,
     default_config: PyDoughConfigs,
     get_plan_test_filename: Callable[[str], str],
-    update_plan_tests: bool,
+    update_tests: bool,
 ) -> None:
     """
     Tests that a PyDough unqualified node can be correctly translated to its
@@ -674,7 +674,7 @@ def test_pipeline_until_relational(
         qualified, PyDoughCollectionQDAG
     ), "Expected qualified answer to be a collection, not an expression"
     relational: RelationalRoot = convert_ast_to_relational(qualified, default_config)
-    if update_plan_tests:
+    if update_tests:
         with open(file_path, "w") as f:
             f.write(relational.to_tree_string() + "\n")
     else:

tests/test_pydough_to_sql.py

@@ -25,42 +25,41 @@
 
 
 @pytest.mark.parametrize(
-    "pydough_code, expected_sql",
-    # Note: All of these tests are for simple code because the
-    # exact SQL generation for inner expressions is currently
-    # non-deterministic.
+    "pydough_code, test_name",
     [
         pytest.param(
             simple_scan,
-            "SELECT o_orderkey AS key FROM tpch.ORDERS",
+            "simple_scan",
             id="simple_scan",
         ),
         pytest.param(
             simple_filter,
-            "SELECT o_orderkey, o_totalprice FROM (SELECT o_orderkey AS o_orderkey, o_totalprice AS o_totalprice FROM tpch.ORDERS) WHERE o_totalprice < 1000.0",
+            "simple_filter",
             id="simple_filter",
         ),
         pytest.param(
             rank_a,
-            "SELECT ROW_NUMBER() OVER (ORDER BY acctbal DESC NULLS FIRST) AS rank FROM (SELECT c_acctbal AS acctbal FROM tpch.CUSTOMER)",
+            "rank_a",
             id="rank_a",
         ),
         pytest.param(
             rank_b,
-            " SELECT RANK() OVER (ORDER BY order_priority NULLS LAST) AS rank FROM (SELECT o_orderpriority AS order_priority FROM tpch.ORDERS)",
+            "rank_b",
             id="rank_b",
         ),
         pytest.param(
             rank_c,
-            "SELECT order_date, DENSE_RANK() OVER (ORDER BY order_date NULLS LAST) AS rank FROM (SELECT o_orderdate AS order_date FROM tpch.ORDERS)",
+            "rank_c",
             id="rank_c",
         ),
     ],
 )
-def test_pydough_to_sql(
+def test_pydough_to_sql_tpch(
     pydough_code: Callable[[], UnqualifiedNode],
-    expected_sql: str,
+    test_name: str,
     get_sample_graph: graph_fetcher,
+    get_sql_test_filename: Callable[[str], str],
+    update_tests: bool,
 ) -> None:
     """
     Tests that a PyDough unqualified node can be correctly translated to its
@@ -69,26 +68,36 @@ def test_pydough_to_sql(
     graph: GraphMetadata = get_sample_graph("TPCH")
     root: UnqualifiedNode = init_pydough_context(graph)(pydough_code)()
     actual_sql: str = to_sql(root, metadata=graph).strip()
-    expected_sql = expected_sql.strip()
-    assert actual_sql == expected_sql
+    file_path: str = get_sql_test_filename(test_name)
+    if update_tests:
+        with open(file_path, "w") as f:
+            f.write(actual_sql + "\n")
+    else:
+        with open(file_path) as f:
+            expected_relational_string: str = f.read()
+        assert (
+            actual_sql == expected_relational_string.strip()
+        ), "Mismatch between tree generated SQL text and expected SQL text"
 
 
 @pytest.mark.parametrize(
-    "pydough_code,expected_sql,graph_name",
+    "pydough_code,test_name,graph_name",
     [
         pytest.param(
             hour_minute_day,
-            """SELECT transaction_id, _expr0, _expr1, _expr2 FROM (SELECT transaction_id AS ordering_0, _expr0, _expr1, _expr2, transaction_id FROM (SELECT _expr0, _expr1, _expr2, symbol, transaction_id FROM (SELECT EXTRACT(HOUR FROM date_time) AS _expr0, EXTRACT(MINUTE FROM date_time) AS _expr1, EXTRACT(SECOND FROM date_time) AS _expr2, ticker_id, transaction_id FROM (SELECT sbTxDateTime AS date_time, sbTxId AS transaction_id, sbTxTickerId AS ticker_id FROM main.sbTransaction)) LEFT JOIN (SELECT sbTickerId AS _id, sbTickerSymbol AS symbol FROM main.sbTicker) ON ticker_id = _id) WHERE symbol IN ('AAPL', 'GOOGL', 'NFLX')) ORDER BY ordering_0""",
+            "hour_minute_day",
             "Broker",
             id="hour_minute_day",
         ),
     ],
 )
 def test_pydough_to_sql_defog(
     pydough_code: Callable[[], UnqualifiedNode],
-    expected_sql: str,
+    test_name: str,
     graph_name: str,
     defog_graphs: graph_fetcher,
+    get_sql_test_filename: Callable[[str], str],
+    update_tests: bool,
 ) -> None:
     """
     Tests that a PyDough unqualified node can be correctly translated to its
@@ -97,5 +106,13 @@ def test_pydough_to_sql_defog(
     graph: GraphMetadata = defog_graphs(graph_name)
     root: UnqualifiedNode = init_pydough_context(graph)(pydough_code)()
     actual_sql: str = to_sql(root, metadata=graph).strip()
-    expected_sql = expected_sql.strip()
-    assert actual_sql == expected_sql
+    file_path: str = get_sql_test_filename(test_name)
+    if update_tests:
+        with open(file_path, "w") as f:
+            f.write(actual_sql + "\n")
+    else:
+        with open(file_path) as f:
+            expected_relational_string: str = f.read()
+        assert (
+            actual_sql == expected_relational_string.strip()
+        ), "Mismatch between tree generated SQL text and expected SQL text"

tests/test_qdag_conversion.py

@@ -2200,7 +2200,7 @@ def test_ast_to_relational(
     tpch_node_builder: AstNodeBuilder,
     default_config: PyDoughConfigs,
     get_plan_test_filename: Callable[[str], str],
-    update_plan_tests: bool,
+    update_tests: bool,
 ) -> None:
     """
     Tests whether the QDAG nodes are correctly translated into Relational nodes
@@ -2210,7 +2210,7 @@ def test_ast_to_relational(
     file_path: str = get_plan_test_filename(file_name)
     collection: PyDoughCollectionQDAG = calc_pipeline.build(tpch_node_builder)
     relational = convert_ast_to_relational(collection, default_config)
-    if update_plan_tests:
+    if update_tests:
         with open(file_path, "w") as f:
             f.write(relational.to_tree_string() + "\n")
     else:
@@ -2336,7 +2336,7 @@ def test_ast_to_relational_alternative_aggregation_configs(
     tpch_node_builder: AstNodeBuilder,
     default_config: PyDoughConfigs,
     get_plan_test_filename: Callable[[str], str],
-    update_plan_tests: bool,
+    update_tests: bool,
 ) -> None:
     """
     Same as `test_ast_to_relational` but with various alternative aggregation
@@ -2350,7 +2350,7 @@ def test_ast_to_relational_alternative_aggregation_configs(
     default_config.avg_default_zero = True
     collection: PyDoughCollectionQDAG = calc_pipeline.build(tpch_node_builder)
     relational = convert_ast_to_relational(collection, default_config)
-    if update_plan_tests:
+    if update_tests:
         with open(file_path, "w") as f:
             f.write(relational.to_tree_string() + "\n")
     else: