New TCK: Fix side effect measurement for properties

[pstutz]

org.opencypher.tools.tck.api.Scenario$ScenarioFailedException: Feature "MergeIntoAcceptance": Scenario "Copying properties from node with ON CREATE" failed with message: 
Expected side effects:
-labels:        0
+labels:        0
+nodes:         0
-nodes:         0
-properties:    0
+properties:    1
-relationships: 0
+relationships: 1
Actual side effects:
-labels:        0
+labels:        0
+nodes:         0
-nodes:         0
-properties:    0
+properties:    0
-relationships: 0
+relationships: 1

org.opencypher.tools.tck.api.Scenario$ScenarioFailedException: Feature "MergeIntoAcceptance": Scenario "Copying properties from node with ON MATCH" failed with message: 
Expected side effects:
-labels:        0
+labels:        0
+nodes:         0
-nodes:         0
-properties:    1
+properties:    1
-relationships: 0
+relationships: 0
Actual side effects:
-labels:        0
+labels:        0
+nodes:         0
-nodes:         0
-properties:    1
+properties:    0
-relationships: 0
+relationships: 0

[szarnyasg]

Update: it seems to me this is related to #268.

I just stumbled upon this and found it interesting (having previously been involved in defining/determining the side effects for the TCK).

The feature MergeIntoAcceptance starts off with the basic graph as:

CREATE (:A {name: 'A'}), (:B {name: 'B'})

Scenario Copying properties from node with ON CREATE runs:

MATCH (a {name: 'A'}), (b {name: 'B'})
MERGE (a)-[r:TYPE]->(b)
  ON CREATE SET r = a

I think this should apply the ON CREATE clause, and copy the properties (name) from node a to relationship r. My local Neo4j 3.3.1 also returns the expected side effects:

Set 1 property, created 1 relationship, completed after 2 ms.

This can also be determined with the Cypher query described in https://github.com/Mats-SX/openCypher/blob/3c797738c5074ecc9aab6d3590a2e7c653bead52/tck/README.adoc#properties.

Scenario Copying properties from node with ON MATCH starts runs:

MATCH (a:A), (b:B)
CREATE (a)-[:TYPE {foo: 'bar'}]->(b)

and

MATCH (a {name: 'A'}), (b {name: 'B'})
MERGE (a)-[r:TYPE]->(b)
  ON MATCH SET r = a

This should delete the foo property of relationship r (-properties: 1) and copy the name property from node a (+properties: 1). For this, my local Neo4j gives:

Set 2 properties, completed after 3 ms.

Which is in sync with -1 and +1 (as -1 can be interpreted as setting the property's value to null).

Is there something I am missing here?

[Mats-SX]

I'll comment more in detail later, but I realised that the Cypher 9 spec that we are writing will actually not include ON MATCH or ON CREATE, so perhaps we can avoid defining the side effects for this particular scenario anyway :)