Add contextual tuples and context to assertions store import and export

[ewanharris]

Describe the problem you'd like to have solved

We added support to the API for Assertions to support context and contextual tuples, given that these are supported in the store file format we should add support for them in the fga store import and fga store export commands.

Describe the ideal solution

Store Import

When importing the assertions in a store file, we should add the contents of context and tuples/tuple_file in a test definition to every

So the following test definition:

Test definition

tests:
  - name: "folder-document-access"
    tuples:
      - user: folder:5
        relation: parent
        object: folder:product-2021
    check: # Each check test is made of: a user, an object and the expected result for one or more relations
      - user: user:anne
        object: folder:product-2021
        context:
          some: "value"
        assertions:
          can_view: true
          can_edit: true

Should produce the following assertions, note that the tuples and context are present in both assertions

Assertions written

{
  "tuple_key": {
    "object": "user:anne",
    "relation": "can_view",
    "user": "folder:product-2021"
  },
  "expectation": true,
  "contextual_tuples": [
    {
      "object": "folder:5",
      "relation": "parent",
      "user": "folder:product-2021"
    }
  ],
  "context": {
    "some": "value"
  }
}

{
  "tuple_key": {
    "object": "user:anne",
    "relation": "can_edit",
    "user": "folder:product-2021"
  },
  "expectation": true,
  "contextual_tuples": [
    {
      "object": "folder:5",
      "relation": "parent",
      "user": "folder:product-2021"
    }
  ],
  "context": {
    "some": "value"
  }
}

Store Export

Warning

This isn't as clear and needs more definition on the behaviour

When exporting a store, we should each ModelTestCheck should maintain its own context but the contextual_tuples should most likely be merged together into the tuples on the top level ModelTest.

/assertions response

{
  "authorization_model_id": "01G5JAVJ41T49E9TT3SKVS7X1J",
  "assertions": [
    {
      "tuple_key": {
        "object": "user:anne",
        "relation": "can_view",
        "user": "folder:product-2021"
      },
      "expectation": true,
      "contextual_tuples": [
        {
          "object": "folder:5",
          "relation": "parent",
          "user": "folder:product-2021"
        }
      ],
      "context": {
        "some": "value"
      }
    },
    {
      "tuple_key": {
        "object": "user:anne",
        "relation": "can_edit",
        "user": "folder:product-2021"
      },
      "expectation": true,
      "contextual_tuples": [
        {
          "object": "folder:5",
          "relation": "parent",
          "user": "folder:product-2021"
        }
      ],
      "context": {
        "some": "value"
      }
    }
  ]
}

Test definition

tests:
  - name: "folder-document-access"
    tuples:
      - user: folder:5
        relation: parent
        object: folder:product-2021
    check: # Each check test is made of: a user, an object and the expected result for one or more relations
      - user: user:anne
        object: folder:product-2021
        context:
          some: "value"
        assertions:
          can_view: true
          can_edit: true

Should produce the following assertions, note that the tuples and context are present in both assertions

Additional context

This needs this PR in go-sdk to be merged and ship before it can be done.

The playground UI currently does not support adding either of these or sending either of them as part of the Check call if they exist