added score expression

Author: daniel-sanche

packages/google-cloud-firestore/google/cloud/firestore_v1/pipeline_expressions.py

@@ -2938,6 +2938,22 @@ def __init__(self):
         super().__init__("rand", [], use_infix_repr=False)
 
 
+class Score(FunctionExpression):
+    """Evaluates to the search score that reflects the topicality of the document
+    to all of the text predicates (`queryMatch`)
+    in the search query. If `SearchOptions.query` is not set or does not contain
+    any text predicates, then this topicality score will always be `0`.
+
+    Note: This Expression can only be used within a `Search` stage.
+
+    Returns:
+        A new `Expression` representing the score operation.
+    """
+
+    def __init__(self):
+        super().__init__("score", [], use_infix_repr=False)
+
+
 class DocumentMatches(BooleanExpression):
     """Creates a boolean expression for a document match query.
 

packages/google-cloud-firestore/tests/unit/v1/test_pipeline_expressions.py

@@ -820,6 +820,12 @@ def test_document_matches(self):
         assert instance.params == [arg1]
         assert repr(instance) == "DocumentMatches(Query)"
 
+    def test_score(self):
+        instance = expr.Score()
+        assert instance.name == "score"
+        assert instance.params == []
+        assert repr(instance) == "Score()"
+
     def test_greater_than_or_equal(self):
         arg1 = self._make_arg("Left")
         arg2 = self._make_arg("Right")