Invalid JSON numbers

[christianbundy]

It would be great to add a message that's valid except that it violates Number.toString(). For example:

{
  "timestamp": 1e1
}

I'm reasonably sure that this is valid JSON, but validators like SSB-Validate always re-encode with JSON.stringify() before checking the signature, and that would result in:

{
  "timestamp": 10
}

I think we can safely use a number on integers where -1e21 < x < 1e21, and use scientific notation outside of that, but I don't remember how this works with decimals. Something something "20 decimal digits" something something? :shrug:

[christianbundy]

In other words, I'd love to add two tests:

• Messages that use scientific notation on numbers with fewer than 20 digits (valid JSON, invalid SSB message)
• Messages that use non-scientific notation on numbers with greater than 20 digits (invalid JSON (I think?), invalid SSB message)

[christianbundy]

Actually, writing invalid JSON might be unwise, since this repository is supposed to have valid JSON only. Maybe just the first test is necessary, and the second test can be checked by some JSON parsing dataset.

[christianbundy]

https://www.ecma-international.org/ecma-262/6.0/#sec-tostring-applied-to-the-number-type