{
"name": "subject-whitespace-normalization",
"description": "Tabs and repeated whitespace collapse before base-subject comparison.",
"spec": {
"source": "RFC 5256",
"url": "https://www.rfc-editor.org/rfc/rfc5256",
"behavior": "tabs and continuations are converted to spaces, and multiple spaces are converted to a single space"
},
"input": [
{
"id": "whitespace-root",
"message_id": "<whitespace-root@example>",
"in_reply_to": null,
"references": [],
"subject": "Quarterly plan",
"date": "2026-05-15T09:00:00Z"
},
{
"id": "whitespace-reply",
"message_id": "<whitespace-reply@example>",
"in_reply_to": null,
"references": [],
"subject": "Re:\tQuarterly plan",
"date": "2026-05-15T09:05:00Z"
}
],
"expected": {
"threads": [
{
"root": "whitespace-root",
"messages": [
"whitespace-root",
"whitespace-reply"
]
}
]
}
}