test improvement.

Author: WaVEV

django_mongodb/compiler.py

@@ -72,12 +72,19 @@ def pre_sql_setup(self, with_col_aliases=False):
                 # the SELECT clause are already part of the GROUP BY.
                 if not is_ref:
                     group_expressions |= set(expr.get_group_by_cols())
+
+            for expr, *_ in self.select:
+                group_expressions |= set(expr.get_group_by_cols())
+
             having_group_by = self.having.get_group_by_cols() if self.having else ()
             for expr in having_group_by:
                 group_expressions.add(expr)
             if isinstance(self.query.group_by, tuple | list):
                 group_expressions |= set(self.query.group_by)
 
+            if self.query.group_by is None:
+                group_expressions = set()
+
             all_strings = "".join(
                 str(col.as_mql(self, self.connection)) for col in group_expressions
             )

django_mongodb/features.py

@@ -38,6 +38,9 @@ class DatabaseFeatures(BaseDatabaseFeatures):
         "expressions.tests.NegatedExpressionTests.test_filter",
         "expressions_case.tests.CaseExpressionTests.test_order_by_conditional_implicit",
         # NotSupportedError: order_by() expression not supported.
+        # Lookup in order_by() not supported:
+        # argument of type '<database function>' is not iterable
+        "aggregation.tests.AggregateTestCase.test_aggregation_order_by_not_selected_annotation_values",
         "db_functions.comparison.test_coalesce.CoalesceTests.test_ordering",
         "db_functions.tests.FunctionTests.test_nested_function_ordering",
         "db_functions.text.test_length.LengthTests.test_ordering",
@@ -124,6 +127,13 @@ class DatabaseFeatures(BaseDatabaseFeatures):
         "queries.test_explain.ExplainUnsupportedTests.test_message",
         # filter() on related model + update() doesn't work.
         "queries.tests.Queries5Tests.test_ticket9848",
+        # Variance is not implemented in mongo as an aggregation,
+        # we should transform it into StdDev * 2.
+        "aggregation.test_filter_argument.FilteredAggregateTests.test_filtered_numerical_aggregates",
+        # Sum returns 0 instead of None in mongodb.
+        "aggregation.test_filter_argument.FilteredAggregateTests.test_plain_annotate",
+        "aggregation.tests.AggregateTestCase.test_annotation_expressions",
+        "aggregation.tests.AggregateTestCase.test_reverse_fkey_annotate",
     }
     # $bitAnd, #bitOr, and $bitXor are new in MongoDB 6.3.
     _django_test_expected_failures_bitwise = {
@@ -299,6 +309,7 @@ def django_test_expected_failures(self):
             "timezones.tests.NewDatabaseTests.test_query_annotation",
         },
         "Exists is not supported on MongoDB.": {
+            "aggregation.test_filter_argument.FilteredAggregateTests.test_filtered_aggregate_ref_multiple_subquery_annotation",
             "annotations.tests.NonAggregateAnnotationTestCase.test_annotation_exists_none_query",
             "delete_regress.tests.DeleteTests.test_self_reference_with_through_m2m_at_second_level",
             "expressions.tests.BasicExpressionsTests.test_annotation_with_deeply_nested_outerref",
@@ -343,6 +354,14 @@ def django_test_expected_failures(self):
             "queries.tests.Ticket22429Tests.test_ticket_22429",
         },
         "Subquery is not supported on MongoDB.": {
+            "aggregation.tests.AggregateAnnotationPruningTests.test_referenced_composed_subquery_requires_wrapping",
+            "aggregation.tests.AggregateAnnotationPruningTests.test_referenced_subquery_requires_wrapping",
+            "aggregation.tests.AggregateTestCase.test_aggregation_nested_subquery_outerref",
+            "aggregation.tests.AggregateTestCase.test_aggregation_subquery_annotation",
+            "aggregation.tests.AggregateTestCase.test_aggregation_subquery_annotation_multivalued",
+            "aggregation.tests.AggregateTestCase.test_aggregation_subquery_annotation_related_field",
+            "aggregation.tests.AggregateTestCase.test_aggregation_subquery_annotation_values",
+            "aggregation.tests.AggregateTestCase.test_aggregation_subquery_annotation_values_collision",
             "annotations.tests.NonAggregateAnnotationTestCase.test_annotation_filter_with_subquery",
             "annotations.tests.NonAggregateAnnotationTestCase.test_annotation_subquery_outerref_transform",
             "annotations.tests.NonAggregateAnnotationTestCase.test_empty_queryset_annotation",
@@ -519,6 +538,7 @@ def django_test_expected_failures(self):
             "queries.tests.Queries6Tests.test_col_alias_quoted",
         },
         "Test executes raw SQL.": {
+            "aggregation.tests.AggregateTestCase.test_coalesced_empty_result_set",
             "annotations.tests.NonAggregateAnnotationTestCase.test_raw_sql_with_inherited_field",
             "delete_regress.tests.DeleteLockingTest.test_concurrent_delete",
             "expressions.tests.BasicExpressionsTests.test_annotate_values_filter",
@@ -610,6 +630,7 @@ def django_test_expected_failures(self):
             "model_fields.test_jsonfield.TestQuerying.test_none_key_exclude",
         },
         "Randomized ordering isn't supported by MongoDB.": {
+            "aggregation.tests.AggregateTestCase.test_aggregation_random_ordering",
             "ordering.tests.OrderingTests.test_random_ordering",
         },
         "Queries without a collection aren't supported on MongoDB.": {
@@ -625,6 +646,7 @@ def django_test_expected_failures(self):
             "aggregation.tests.AggregateAnnotationPruningTests.test_non_aggregate_annotation_pruned",
             "aggregation.tests.AggregateTestCase.test_add_implementation",
             "aggregation.tests.AggregateTestCase.test_aggregation_default_using_datetime_from_database",
+            "aggregation.tests.AggregateTestCase.test_multi_arg_aggregate",
             # SQL custom values.
             "aggregation.tests.AggregateTestCase.test_aggregation_default_using_date_from_database",
             # No sql generate
@@ -636,7 +658,17 @@ def django_test_expected_failures(self):
             "aggregation.tests.AggregateAnnotationPruningTests.test_referenced_aggregate_annotation_kept",
             # Using a QuerySet in annotate() is not supported on MongoDB
             "aggregation.tests.AggregateTestCase.test_group_by_subquery_annotation",
-        }
+            # Query set with annotate not supported.
+            "aggregation.tests.AggregateTestCase.test_group_by_reference_subquery",
+            "aggregation.tests.AggregateTestCase.test_filter_in_subquery_or_aggregation",
+            # Exists is not supported in mongodb
+            "aggregation.tests.AggregateTestCase.test_aggregation_exists_multivalued_outeref",
+            "aggregation.tests.AggregateTestCase.test_group_by_exists_annotation",
+            "aggregation.tests.AggregateTestCase.test_exists_none_with_aggregate",
+            "aggregation.tests.AggregateTestCase.test_exists_extra_where_with_aggregate",
+            # Queryset dates not supported
+            "aggregation.tests.AggregateTestCase.test_dates_with_aggregation",
+        },
     }
 
     @cached_property

django_mongodb/functions.py

@@ -86,6 +86,8 @@ def aggregate(self, compiler, connection, **extra_context):  # noqa: ARG001
         node = self
     lhs_mql = process_lhs(node, compiler, connection)
     operator = MONGO_AGGREGATION.get(self.__class__)
+    if self.__class__ in (StdDev, Variance) and "_SAMP" in self.functions:
+        operator = operator.replace("Pop", "Samp")
     return {f"${operator}": lhs_mql}