PYTHON-3319 Require contentionFactor for "Indexed" explicit encryption (#987)

Author: blink1073

pymongo/encryption.py

@@ -620,7 +620,9 @@ def encrypt(
           - `query_type` (str): **(BETA)** The query type to execute. See
             :class:`QueryType` for valid options.
           - `contention_factor` (int): **(BETA)** The contention factor to use
-            when the algorithm is :attr:`Algorithm.INDEXED`.
+            when the algorithm is :attr:`Algorithm.INDEXED`.  An integer value
+            *must* be given when the :attr:`Algorithm.INDEXED` algorithm is
+            used.
 
         .. note:: `index_key_id`, `query_type`, and `contention_factor` are part of the
            Queryable Encryption beta. Backwards-breaking changes may be made before the

test/test_encryption.py

@@ -2098,13 +2098,15 @@ def setUp(self):
 
     def test_01_insert_encrypted_indexed_and_find(self):
         val = "encrypted indexed value"
-        insert_payload = self.client_encryption.encrypt(val, Algorithm.INDEXED, self.key1_id)
+        insert_payload = self.client_encryption.encrypt(
+            val, Algorithm.INDEXED, self.key1_id, contention_factor=0
+        )
         self.encrypted_client[self.db.name].explicit_encryption.insert_one(
             {"encryptedIndexed": insert_payload}
         )
 
         find_payload = self.client_encryption.encrypt(
-            val, Algorithm.INDEXED, self.key1_id, query_type=QueryType.EQUALITY
+            val, Algorithm.INDEXED, self.key1_id, query_type=QueryType.EQUALITY, contention_factor=0
         )
         docs = list(
             self.encrypted_client[self.db.name].explicit_encryption.find(
@@ -2125,9 +2127,8 @@ def test_02_insert_encrypted_indexed_and_find_contention(self):
                 {"encryptedIndexed": insert_payload}
             )
 
-        # Find without contention_factor non-deterministically returns 0-9 documents.
         find_payload = self.client_encryption.encrypt(
-            val, Algorithm.INDEXED, self.key1_id, query_type=QueryType.EQUALITY
+            val, Algorithm.INDEXED, self.key1_id, query_type=QueryType.EQUALITY, contention_factor=0
         )
         docs = list(
             self.encrypted_client[self.db.name].explicit_encryption.find(
@@ -2168,7 +2169,9 @@ def test_03_insert_encrypted_unindexed(self):
 
     def test_04_roundtrip_encrypted_indexed(self):
         val = "encrypted indexed value"
-        payload = self.client_encryption.encrypt(val, Algorithm.INDEXED, self.key1_id)
+        payload = self.client_encryption.encrypt(
+            val, Algorithm.INDEXED, self.key1_id, contention_factor=0
+        )
         decrypted = self.client_encryption.decrypt(payload)
         self.assertEqual(decrypted, val)