How can I explictly constrain multiple items in a JSON Schema array? - json

Question

I am creating a JSON schema and want to define an array containing only exact matches for certain items:
An example of the sort of JSON (snippet) would look like:
{
"results":
[
{ "id": 1, "test": true, "volts": 700, "duration": 100 },
{ "id": 2, "test": false }
]
}
This seems to be a combination of OneOf and "additionalProperties": false but I can't work out how that should be used. So far I have:
{
"results":
{
"type": "array",
"items":
{
"type": "object",
"OneOf":
[
{
"id": { "type": "integer" },
"test": { "type": "boolean" },
"volts": { "type": "integer" },
"duration": { "type": "integer" }
},
{
"id": { "type": "integer" },
"test": { "type": "boolean" }
}
],
"additionalProperties": false
}
}
}
I'm using http://www.jsonschemavalidator.net/ to check my JSON.
But when I validate the following JSON against my schema it says it's valid; is the website incorrect or have I done something wrong?
{
"results": [
{
"fred": 7,
"id": 7,
"test": true,
"volts": 7,
"duration": 7
},
{
"fish": 7
}
]
}