BUG23582703: Fix issue while using array_insert in Collection

This patch fixes `array_insert` in `Collection` that was not returning
a `DocumentPathItem` object for arrays, thus raising an error.

A new test was added for regression.

Author: nmariz

lib/mysqlx/expr.py

@@ -443,14 +443,14 @@ def docpath_array_loc(self):
         self.consume_token(TokenType.LSQBRACKET)
         if self.cur_token_type_is(TokenType.MUL):
             self.consume_token(TokenType.RSQBRACKET)
-            return "[*]"
+            return DocumentPathItem(type=DocumentPathItem.ARRAY_INDEX_ASTERISK)
         elif self.cur_token_type_is(TokenType.LNUM):
             v = int(self.consume_token(TokenType.LNUM))
             if v < 0:
                 raise IndexError("Array index cannot be negative at {0}"
                                  "".format(self.pos))
             self.consume_token(TokenType.RSQBRACKET)
-            return "[" + str(v) + "]"
+            return DocumentPathItem(type=DocumentPathItem.ARRAY_INDEX, index=v)
         else:
             raise ValueError("Exception token type MUL or LNUM in JSON "
                              "path array index at token pos {0}"

tests/test_mysqlx_crud.py

@@ -333,6 +333,19 @@ def test_parameter_binding(self):
         self.assertEqual(1, len(docs))
         self.assertEqual("Wilma", docs[0]["name"])
 
+    def test_array_insert(self):
+        collection_name = "collection_test"
+        collection = self.schema.create_collection(collection_name)
+        collection.add(
+            {"_id": 1, "name": "Fred", "cards": []},
+            {"_id": 2, "name": "Barney", "cards": [1, 2, 4]},
+            {"_id": 3, "name": "Wilma", "cards": []},
+            {"_id": 4, "name": "Betty", "cards": []},
+        ).execute()
+        collection.modify("$._id == 2").array_insert("$.cards[2]", 3).execute()
+        docs = collection.find("$._id == 2").execute().fetch_all()
+        self.assertEqual([1, 2, 3, 4], docs[0]["cards"])
+
     def test_array_append(self):
         collection_name = "collection_test"
         collection = self.schema.create_collection(collection_name)
@@ -346,6 +359,7 @@ def test_array_append(self):
         docs = collection.find("$._id == 2").execute().fetch_all()
         self.assertEqual([1, [2, 3], 4], docs[0]["cards"])
 
+
 @unittest.skipIf(tests.MYSQL_VERSION < (5, 7, 12), "XPlugin not compatible")
 class MySQLxTableTests(tests.MySQLxTests):