An ActivityPub Object `likes` Collection Must be a Collection

An ActivityPub Test

Background

Every object MAY have a likes collection. … The likes collection MUST be either an OrderedCollection or a Collection

About This Test

This is a Test Case describing a rule to determine whether an ActivityPub Object is in partial conformance with the following behaviors required by ActivityPub.

requirement f965e989-4084-4f9d-9119-6a7ea13bcb64 - The likes collection MUST be either an OrderedCollection or a Collection

Identifier

The identifier of this test is urn:uuid:200b9bc8-aae3-46f2-a6ab-5366042c0f6e.

Test Subject

The subject of this test is an ActivityPub Object.

Input

This test requires the following inputs indicating parts of the test subject:

`input.object`

the object whose likes property will be tested

type: binary
constraints
- should be JSON

Applicability

This test applies to each of the likes collections derived from the values of the property on object named likes.

Prerequisites

object is a JSON object
object JSON object has a property named likes

Test Targets

How to Derive Test Targets from Input

let targets be a set
let likesValues be the result of
- if object.likes is an Array, return it
- else return an Array whose only item is the value of object.likes
for each item in likesValues
- if item is a string
  - let itemFetched be the result of interpreting the string as an ActivityPub Object Identifier and fetching the corresponding ActivityPub Object.
  - add itemFetched to targets
- else add item to targets
return targets

Expectations

For every target target

target is a JSON object
target has a property named type
the value of the target's type property must be one of
- an array containing the string "Collection"
- an array containing the string "OrderedCollection"
- the string "Collection"
- the string "OrderedCollection"

Test Cases

What follows are some specific cases of applything this test rule.

Passed Example 1

inputs

object:

{
  "likes": {
    "type": "Collection"
  }
}

test targets

```
{
  "type": "Collection"
}
```
- outcome: passed

Passed Example 2

inputs

object:

{
  "likes": {
    "type": "OrderedCollection"
  }
}

test targets

```
{
  "type": "OrderedCollection"
}
```
- outcome: passed

Passed Example 3

inputs

object:

{
  "likes": {
    "type": ["FancyCollection", "OrderedCollection"]
  }
}

test targets

```
{
  "likes": {
    "type": ["FancyCollection", "OrderedCollection"]
  }
}
```
- outcome: passed
  - rationale: "FancyCollection" is not well-defined here, but this object still passes the test because at least one of the type property values is OrderedCollection and thus satisfies the requirement as interpreted.

Failed Example 1 - Likes is a number

inputs

object:
```
{
  "likes": 1
}
```

test targets

```
1
```
- outcome: failed

Failed Example 2 - Likes is an empty object

inputs

object:
```
{
  "likes": {}
}
```

test targets

```
{}
```
- outcome: failed

Failed Example 3 - Likes object type is array including only `"Link"`

inputs

object:

{
  "likes": {
    "type": ["Link"]
  }
}

test targets

```
{
  "type": ["Link"]
}
```
- outcome: failed

Inapplicable Example 1

inputs

object:
```
1
```

result

outcome: inapplicable

Inapplicable Example 2 - object has no likes property

inputs

object:
```
{ "foo": "bar" }
```

result

outcome: inapplicable

Inapplicable Example 3 - object is html

inputs

object:
```
<!doctype html>hi
```

result

outcome: inapplicable

Glossary ^?

`outcome`

An outcome is a conclusion that comes from evaluating a test on a test subject. An outcome can be one of the three following types:

inapplicable: No part of the test subject matches the applicability
passed: A test target meets all expectations
failed: A test target does not meet all expectations

Requirements Mapping ^?

ActivityPub requirement f965e989-4084-4f9d-9119-6a7ea13bcb64 - The likes collection MUST be either an OrderedCollection or a Collection
- Required for Conformance to ActivityPub
- Outcome Mapping
  - when every test target has outcome passed, the requirement is satisfied by the test subject
  - when any test target has outcome failed, the requirement is not satisfied by the test subject
  - when any test target has outcome inapplicable, further testing is needed to determine requirement satisfaction

Issues ^?

Change Log

2023-12-06T06:48:14.689Z: init
2023-12-18T04:33:22.670Z: add more example cases that were useful for maximizing implementation code coverage

Background

About This Test

Identifier

Test Subject

Input

input.object

Applicability

Prerequisites

Test Targets

Expectations

Test Cases

Passed Example 1

Passed Example 2

Passed Example 3

Failed Example 1 - Likes is a number

Failed Example 2 - Likes is an empty object

Failed Example 3 - Likes object type is array including only "Link"

Inapplicable Example 1

Inapplicable Example 2 - object has no likes property

Inapplicable Example 3 - object is html

Glossary ?

outcome

Requirements Mapping ?

Issues ?

Change Log

`input.object`

Failed Example 3 - Likes object type is array including only `"Link"`

Glossary ^?

`outcome`

Requirements Mapping ^?

Issues ^?