add support for NegatedExpression

Author: timgraham

.github/workflows/test-python.yml

@@ -76,6 +76,7 @@ jobs:
           datetimes
           db_functions
           empty
+          expressions.tests.NegatedExpressionTests
           defer
           defer_regress
           from_db_value

django_mongodb/expressions.py

@@ -1,4 +1,4 @@
-from django.db.models.expressions import Col, ExpressionWrapper, Value
+from django.db.models.expressions import Col, ExpressionWrapper, NegatedExpression, Value
 
 
 def col(self, compiler, connection):  # noqa: ARG001
@@ -9,11 +9,16 @@ def expression_wrapper(self, compiler, connection):
     return self.expression.as_mql(compiler, connection)
 
 
+def negated_expression(self, compiler, connection):
+    return {"$not": expression_wrapper(self, compiler, connection)}
+
+
 def value(self, compiler, connection):  # noqa: ARG001
     return {"$literal": self.value}
 
 
 def register_expressions():
     Col.as_mql = col
     ExpressionWrapper.as_mql = expression_wrapper
+    NegatedExpression.as_mql = negated_expression
     Value.as_mql = value

django_mongodb/features.py

@@ -197,6 +197,7 @@ class DatabaseFeatures(BaseDatabaseFeatures):
             "annotations.tests.AliasTests.test_order_by_alias",
             "annotations.tests.NonAggregateAnnotationTestCase.test_order_by_aggregate",
             "annotations.tests.NonAggregateAnnotationTestCase.test_order_by_annotation",
+            "expressions.tests.NegatedExpressionTests.test_filter",
             # annotate().filter().count() gives incorrect results.
             "db_functions.datetime.test_extract_trunc.DateFunctionTests.test_extract_year_exact_lookup",
         },