toContainNumericIDs

[M-Scott-Lassiter]

Description

GeoJSON Features have an optional ID member that can be any string or number. This matcher verifies that all Features within a FeatureCollection contain IDs and that they are all type number.

If a Feature has a commonly used identifier, that identifier SHOULD be included as a member of the Feature object with the name "id", and the value of this member is either a JSON string or number.

~ https://datatracker.ietf.org/doc/html/rfc7946#section-3.2

An "id" member on a non-feature object gets treated as a foreign member instead of an ID. Therefore, this matcher rejects non-FeatureCollection objects.

This test will fail if any of the IDs have a type string, do not have an ID, or if the "features" member is an empty array.

Example Matcher Usage

const goodTtestCollection = {
    type: "FeatureCollection",
    features: [{
        type: "Feature",
        geometry: {...},
        properties: {...},
        id: 1
    }, {
        type: "Feature",
        geometry: {...},
        properties: {...},
        id: 2
    }, {
        type: "Feature",
        geometry: {...},
        properties: {...},
        id: 3
    }]
}
const badTestCollection1 = {
    type: "FeatureCollection",
    features: [{
        type: "Feature",
        geometry: {...},
        properties: {...},
        id: "Test 1"
    }, {
        type: "Feature",
        geometry: {...},
        properties: {...},
        id: 2
    }]
}

const badTestCollection2 = {
    type: "FeatureCollection",
    features: [{
        type: "Feature",
        geometry: {...},
        properties: {...},
        id: 11
    }, {
        type: "Feature",
        geometry: {...},
        properties: {...},
    }]
}

expect(goodTtestCollection).toContainNumericIDs()

expect(badTestCollection1).not.toContainNumericIDs()
expect(badTestCollection2).not.toContainNumericIDs()
expect(goodTtestCollection.features[0]).not.toContainNumericIDs()

Passing Tests

Unique Numeric IDs

• FeatureCollection with Single Feature with ID
• FeatureCollection with 5 Features and unique IDs
• Stress Test: FeatureCollection with 100 Features and unique IDs

Identical Numeric IDs

• FeatureCollection with 5 Features and some repeated IDs
• FeatureCollection with 5 Features and all repeated IDs

Failing Tests

Invalid Inputs To Matcher

Rejects each of the following:

• Each of the seven Geometry objects
• FeatureCollection object
• undefined, null, false, true, 0
• { someProp: 'I am not GeoJSON', id: 4 }
• '',
• 'Random Feature',

• JSON.stringify({
        type: 'FeatureCollection',
        features: []
    })

Only Some Have Numeric IDs, the Rest Null or Not Mentioned

• FeatureCollection with 5 Features, 1 has no "id" member
• FeatureCollection with 5 Features, 1 has an "id" member with null

FeatureCollection with Empty Features Array

Should fail because there are no features to check IDs on.

FeatureCollection with No ID

Should fail with a single feature that has no ID.

All Have String IDs

• FeatureCollection with Single Feature and ID
• FeatureCollection with 5 Features and unique IDs
• FeatureCollection with 5 Features and repeated IDs

Only Some Have String IDs, the Rest Numeric ID, Null, or Not Mentioned

• FeatureCollection with 5 Features
• FeatureCollection with 100 Features